Final

Assessment of Occupational Exposure to 

Formaldehyde From

Composite Wood Products

U.S. Environmental Protection Agency

Office of Pollution Prevention and Toxics

Chemical Engineering Branch

1200 Pennsylvania Avenue NW

Washington, DC 20460

6 October 2011
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Executive Summary

Introduction

This assessment of the occupational exposure to formaldehyde from composite wood products 

was developed to support EPA rulemaking under the Formaldehyde Standards for Composite 

Wood Products Act (FSCWPA).

In July 2010, President Obama signed into law the FSCWPA. This law is an amendment to 

TSCA and directs EPA to regulate the formaldehyde emissions from hardwood plywood 

(HWPW), medium-density fiberboard (MDF), and particleboard (PB). FSCWPA sets 

formaldehyde limits equal to the California Air Resources Board (CARB) Airborne Toxic 

Control Measure (ATCM) promulgated in 2007. As part of the development of the rule under 

FSCWPA, EPA is conducting a cost-benefit analysis of implementing the formaldehyde limits 

cited by FSCWPA. In support of this cost-benefit analysis, EPA assessed occupational exposure 

to formaldehyde during the life cycle of HWPW, PB, and MDF.

Purpose and Scope

The purpose of the assessment is, first, the prediction of baseline formaldehyde inhalation and 

dermal occupational exposures that are due to all sources of exposure (aggregate exposure) 

during the life cycle of composite wood products (CWPs), and, second, the determination of the 

effects on baseline exposures of the analytical options for limits on emission levels for offgassing from HWPW, PB, and MDF.

The baseline occurs in the year in which EPA will promulgate limits under FSCWPA, which will 

be 2013. The analytical options consist of the following limits on off-gassing emissions for 

HWPW, PB, and MDF:

 Option 1: emission limits equal to the CARB ATCM Phase 1 limits;

 Option 2: emission limits equal to the CARB ATCM Phase 2 limits (which are 

equal to the limits specified in FSCWPA); and

 Option 3: emission limits equal to the no-added formaldehyde (NAF) limits 

specified in FSCWPA.

The assessed life cycle stages include the following:

1. Manufacture of HWPW, PB and MDF within the United States (domestic 

manufacturing);

2. Manufacture of products constructed with domestically-manufactured and 

imported HWPW, PB and MDF (secondary products) such as the manufacture of 

furniture (also referred to as composite wood product fabrication);

3. Wholesale and retail of domestically-manufactured and imported HWPW, PB, 

and MDF and downstream products; and

4. Office building occupancy and associated use of office furniture fabricated with 

domestically-manufactured and imported HWPW, PB, and MDF.
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The following life cycle stages were not assessed due to data gaps in information needed for their 

assessment: the commercial use of HWPW, PB, and MDF and their secondary products in 

construction work, and the recycling and disposal of HWPW, PB, and MDF and their secondary

products.

Approach

Inhalation exposure monitoring data were compiled for all of the assessed life cycle stages but 

were not deemed to be adequate for assessment purposes. Time-weighted average (TWA) 

inhalation exposure monitoring data for sites in which the manufacture, fabrication, wholesale 

and retail of the three composite wood products likely occurs were compiled from the OSHA 

Integrated Management Information System (IMIS) database. Inhalation exposure monitoring 

data for office buildings were compiled from EPA’s Building Assessment Survey and Evaluation 

(BASE) study, which was conducted from 1994 through 1998. As explained in Section 3.2, 

these monitoring data were deemed not adequate for the assessment of baseline exposures and 

the effects of the analytical options on baseline exposures, which were assessed using 

mathematical modeling where possible. The compiled monitoring data are presented for 

perspective only.

Baseline average inhalation exposures in composite wood fabrication sites and in office 

buildings and the effects of analytical options on these inhalation exposures were assessed using 

mathematical models for the estimation of indoor air concentrations in combination with 

estimates of exposure duration (the hours of exposure per day) and frequency (the days of 

exposure per year). For composite wood fabrication, exposure duration and frequency were 

estimated using census data on pre-baseline aggregate production hours.

Inhalation exposures in the manufacturing, wholesale, and retail life cycle stages were assessed 

qualitatively due to gaps in data needed for mathematically modeling indoor air concentration.

Dermal exposures to formaldehyde in liquid mixtures were quantitatively assessed using EPA 

dermal exposure models for CWP manufacturing for pre-baseline conditions only due to data 

gaps. Dermal exposures to CWPs are not quantifiable using the EPA dermal exposure models 

for liquids and solids and, therefore, dermal exposure was not assessed for the CWP fabrication, 

wholesale, retail and office occupancy life cycle stages.

For all life cycle stages with the exception of occupancy of office buildings, the number of 

exposed workers was estimated based on aggregate census data (Census 2007a). The number of 

exposed office workers was not determined due to data gaps. The extent of use of personal 

protective equipment (PPE) was noted for manufacture and fabrication based on a review of 

OSHA inspection reports. However, a limited number of inspection reports were available for 

review and a conclusion as to the prevalence of the use of respiratory protection in these life 

cycle stages could not be made.

Average formaldehyde indoor air concentrations in a CWP fabrication site and an office building 

were estimated using mathematical models that are based on the principle of mass conservation 

and the assumption that the work space is a well mixed box. In these steady-state models the 

generation rate of formaldehyde due to off-gassing from CWPs is equated to the rate at which 

airborne formaldehyde is exhausted from the work space through ventilation with outdoor air to 

satisfy a formaldehyde mass balance on the work space. The generation rate was expressed as 
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the product of a formaldehyde off-gassing emission rate and an amount of emitting surface area. 

The formaldehyde off-gassing emission rate was determined from average emission levels for 

the three composite wood products that would be domestically produced or imported at the 

baseline (provided in the EPA report Market Profile for Industries Potentially Affected by the 

Proposed Formaldehyde Standards for Composite Wood Products Rule (USEPA 2010a)) and 

under the analytical options (provided in the EPA report Formaldehyde from Pressed Wood 

Products: Exposure Assessment (USEPA 2009b)).

Method for Estimating Average Indoor Air Concentration in CWP Fabrication Sites

As discussed in Section 4.2.1, there are indications that sources of formaldehyde other than the 

off-gassing of formaldehyde from CWPs may exist in a CWP fabrication site. Aggregate indoor 

air concentrations are the sum of the concentration contributed by off-gassing of the three CWPs, 

the concentration contributed by other formaldehyde sources in the workplace, and the 

concentration of formaldehyde in ambient outdoor air. However, the extent to which sources in 

a CWP fabrication site other than off-gassing of CWP contribute to indoor air concentration in 

CWP fabrication sites is unknown. Attempts to develop methods to estimate concentration 

contributions from other sources during CWP fabrication were not successful due to data gaps. 

Therefore, only the contributions from off-gassing of the three CWPs and ventilation with 

outdoor ambient air were accounted for in the estimation of aggregate indoor air concentration in 

CWP fabrication sites.

Average indoor air concentration in a CWP fabrication site was calculated from the following

mathematical model parameters:

 Formaldehyde emission rate (off-gassing emissive flux) of the composite wood 

products;

 Total emitting surface area of the composite wood products located in a CWP

fabrication site;

 Effective ventilation rate for an entire CWP fabrication site; and

 The concentration of formaldehyde in the outdoor air for industrial land use areas.

The mathematical model is described in detail in Appendix E. The literature search did not yield 

a CWP fabrication site population distribution for these mathematical model parameters, nor did 

it yield representative values for these parameters for CWP fabrication sites in general (with the 

exception of concentration of formaldehyde in the outdoor air). Due to these data gaps with 

respect to the model parameters, what-if values for indoor air concentration were estimated. This 

what-if analysis was accomplished by estimating the range of possible values for each model 

parameter (with the exception of outside air concentration) and calculating a range of what-if 

indoor air concentration values from the estimated ranges of the model parameters as discussed 

in detail in Section 3.3.1.1. A range of what-if indoor air concentration values was calculated 

assuming a CWP fabrication site contains only a single CWP type. Each model parameter 

(except for outside air concentration) was varied between the two bounding values of its range

(the low- and high-end values) while keeping the other model parameters constant at an average, 

a typical, or an intermediate value. Section 3.3.1.1 describes in detail how an average, a typical, 

or an intermediate value was determined for each model parameter. In this assessment report, an 

intermediate value is defined as a value in-between a low-end and high-end value. This 
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computational procedure resulted in three different low-end indoor air concentration values and 

three different high-end indoor air concentration values. The broadest range of these calculated 

low- and high-end values constitutes a range of values for calculated indoor air concentration for 

a single CWP that is intended to be a broad range that accounts for uncertainty in coinciding 

values for the model parameters. An indoor air concentration value was also calculated from the 

average, typical, or intermediate value of each model parameter. These calculations were 

repeated for each CWP type: HWPW, PB, and MDF.

The low-end values of calculated indoor air concentrations for all three CWP types (a total of 

nine low-end values) were combined into a single range of low-end indoor air concentration 

values. The same procedure was followed for the high-end values for all three CWP types, 

thereby yielding a single range of high-end values. Finally, the intermediate values of indoor air 

concentration for each CWP type were also combined into a single range of intermediate values. 

Therefore, three ranges of indoor air concentration values (one for low-end values, one for

intermediate values, and one for high-end values) were obtained that account for any mixture of 

the different CWP types in a CWP fabrication site.

A final range of results for indoor air concentration was obtained by combining these three 

ranges into a single encompassing range and a best estimate for indoor air concentration was 

chosen as the midpoint of this overall range as discussed in Section 4.2.5.3. The resulting values 

in the estimated range for average indoor air concentration at a CWP fabrication site are 

characterized as what-if results because each concentration value in this range corresponds to 

combination of choices, or what-if values, for the model parameters. Although the prevalence of 

the what-if values for each model parameter at actual CWP fabrication sites is unknown, the 

ranges of the model parameter values should be realistic such that any given choice, or what-if 

value, for any model parameter represents a possible value at actual CWP fabrication sites.

Method for Estimating Average Indoor Air Concentration in Office Buildings

Indoor air concentration in office buildings was estimated using a mathematical model for 

estimation of indoor air concentration resulting from off-gassing emissions from office 

workstations fabricated with the three CWPs. This mathematical model was applied to two 

different office workstation types: open plan workstations and private office workstations. 

Average indoor air concentration in an office building was calculated for each workstation type 

from the following mathematical model parameters:

 Emitting surface area of panels in the workstation;

 Emitting surface area of work surfaces in the workstation;

 The outdoor air ventilation rate that affects the volume of the office building 

containing the workstation;

 Emission rate (emissive flux) of the composite wood products used to construct 

the workstation panels and work surfaces;

 The fraction of the panels’ surface area that is finished, or overlayed, and the 

effectiveness of this finish or overlay as a barrier to off-gassing emissions from 

the CWP substrate;

 Fraction of the work surfaces’ surface area that is finished, or overlayed, and the 

effectiveness of this finish or overlay as a barrier to off-gassing emissions from 

the CWP substrate; and
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 Concentration of formaldehyde in the outdoor air for commercial land use areas.

The mathematical model is described in detail in Appendix E. Representative values for the 

emitting surface area of each workstation component (panel and work surface) and the work 

space ventilation rate were obtained from the Business and Institutional Furniture 

Manufacturer’s Association (BIFMA) / American National Standards Institute (ANSI) M7.1-

2007 standard test method. The workstation component emission rates were estimated using 

CWP emission rates in combination with the extent of finishing or overlay on a workstation 

component and the reduction in the emission rate of the CWP due to the finish or overlay acting 

as a barrier to off-gassing emissions.

Information was not identified on the relative amounts of the three CWPs used in the fabrication 

of office workstations, representative values for the extent to which the workstation components 

are finished or overlayed, and the barrier effectiveness of the finish or overlay. Due to these data 

gaps in information on representative values for these model parameters, what-if values for 

indoor air concentration were estimated. What-if values for indoor air concentration were 

estimated by first estimating the range of possible values for the following parameters: extent of 

finishing or overlay of each workstation component and the barrier effectiveness of the finishing 

or overlay. Next, these estimated ranges of parameter values were used in combination with the 

range of CWP emission rates obtained from the EPA reports mentioned above and the 

representative values for the remaining model parameters to estimate a range of what-if values 

for indoor air concentration in an office building due to each workstation type. A range of whatif indoor air concentration values was calculated assuming a workstation consists of only a single 

CWP type. Low and high ends of the range of what-if average formaldehyde indoor air 

concentrations in the building volume containing a workstation were estimated using the 

mathematical model and (1) the bounding values of the range of values for the model parameters

for which ranges were estimated and (2) the representative values of the remaining model 

parameters so as to obtain a wide range of indoor air concentration. Additionally, an 

intermediate what-if value of indoor air concentration was calculated using average or 

intermediate values for the model parameters for which ranges were estimated and the 

representative values of the remaining model parameters. Section 3.3.1.2 describes in detail how 

an average or intermediate value was determined for each model parameter. In this assessment 

report, an intermediate value is defined as a value in-between a low-end and high-end value.

These calculations were repeated for each CWP type: HWPW, PB, and MDF, thus resulting in 

nine values of what-if indoor air concentrations for each workstation type (a low-end, high-end, 

and intermediate value of what-if indoor air concentration for each of the three CWP types). 

These values were then aggregated into low-end ranges, intermediate ranges, and high-end 

ranges to account for various mixtures of the different CWP types in each office workstation 

type. The best estimate concentration was calculated as the average of the following two values: 

the midpoint of the intermediate range for open plan workstations and the midpoint of the 

intermediate range for private office workstations as discussed in Section 4.5.4.1.

These calculated indoor air concentrations are initial steady-state concentrations resulting from 

off-gassing of office workstations fabricated from new CWPs. Temporal decay in emission rates 

from the CWPs was not accounted for due to data gaps in information necessary for the 

modeling of the temporal decay of CWP emission rates in office buildings.
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Results

The results for each assessed life cycle stage are summarized below.

Results for Manufacturing

At baseline, approximately all domestic production of HWPW, MDF, and PB will be in 

compliance with the CARB ATCM Phase 2 standard. Only small fractions of HWPW and PB 

domestic production will not be in compliance with the CARB ATCM Phase 2 standard at 

baseline. Hence, the CARB Phase 1 and FSCWPA/CARB Phase 2 analytical options will result 

in a negligible effect on baseline exposure levels for manufacturing. Since approximately all 

domestic production of CWPs are expected to meet the CARB ATCM Phase 2 standard at 

baseline, only the NAF analytical option will affect baseline exposures.

NAF resins do not contain any formaldehyde. Therefore, mills that use NAF resins in 

compliance with NAF standards should achieve a reduction in formaldehyde exposures due to 

the elimination of the formaldehyde content of resins. However, wood naturally emits 

formaldehyde, and it is possible that workers in mills that use only NAF resins may still 

experience some formaldehyde exposures due to the natural emission of formaldehyde from 

wood. Other sources of formaldehyde can exist for mills that apply value-added surfaces. 

However, it is uncertain how many mills apply value-added surfaces.

Dermal exposures to workers during manufacturing can occur during unloading of liquid UF 

resin. For the purpose of this assessment, EPA assumes a formaldehyde concentration of 0.59% 

in the UF resin. The EPA/OPPT 2-Hand Dermal Contact with Liquid Model estimates a dermal 

exposure of 590 to 1,800 mg/day for exposure to a chemical at 100% concentration. For the 

assumed formaldehyde concentration of 0.59%, the model estimates worker exposure of 3.5 to 

10.6 mg/day. This results in an estimated dose of 0.05 to 0.15 mg/kg/day for an average 70 kg 

worker. It is uncertain how the free formaldehyde content of CWP resins will change as 

manufacturers adopt the CARB ATCM limits. Therefore, both baseline dermal exposures and 

the effect of analytical options on baseline dermal exposures are uncertain and cannot be 

estimated.

Results for CWP Fabrication

The results of the assessment of indoor air concentrations in CWP fabrication sites at the 

baseline and the effect of the analytical options on baseline indoor air concentrations are 

presented in Table ES-1 through Table ES-4. Table ES-2 provides a summary of the estimates 

of average indoor air concentration in a CWP fabrication site due to off-gassing from the three 

CWP types as a range of values and as a single best estimated value for the baseline and the 

analytical options. Tables ES-3 and ES-4 provide average daily concentration (ADC) and 

lifetime average daily concentration (LADC) values, respectively, that correspond to the values 

given in Table ES-2. The results show that the maximum formaldehyde indoor air concentration

decreases as lower (more stringent) emission standards are implemented. However, the CARB 

ATCM Phase 1 analytical option would result in little or no reduction in exposure from the 

baseline year because most composite wood products are expected to be already meeting more 

stringent standards by the baseline year (2013). The minimum indoor air concentration is 

identical for all of the different analytical options because a small portion of the market is 

expected to be already meeting the NAF standards at the baseline. The emission levels of NAF-
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compliant composite wood products were assumed to remain unchanged and not be affected by 

the analytical options.

Results for Wholesale and Retail

The formaldehyde concentration resulting from off-gassing is expected to decrease with the 

implementation of more stringent regulations. However, as discussed previously, CARB ATCM 

Phase 1 analytical option would result in little or no reduction in exposure from the baseline

year. This effect is because most composite wood products in the market would already be 

meeting more stringent limits by 2013.

Results for Office Buildings

The results of the assessment of indoor air concentrations in office buildings at the baseline and 

the effect of the analytical options on baseline indoor air concentrations are presented in Table 

ES-5 through Table ES-8. Table ES-5 provides for the baseline and each of the analytical 

options the three ranges of estimated indoor air concentration in an office building for each of the 

two types of office furniture workstations. Tables ES-6 and ES-7 provide average daily

concentration (ADC) and lifetime average daily concentration (LADC) values, respectively, that 

correspond to the values given in Table ES-5. Table ES-8 presents the best estimated indoor air 

concentration values from among the results presented in Table ES-5. Similarly as with the 

CWP fabrication results, the office building results show that the maximum formaldehyde indoor 

air concentration decreases as lower (more stringent) emission standards are implemented. 

Again, the minimum indoor air concentrations remain constant throughout the different 

analytical options due to the presence of NAF-compliant products at the baseline. The office 

building results in Table ES-8 show the most significant reduction in indoor air concentration

from the NAF emission limits.
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Table ES-1. Estimated Low-End, Intermediate, and High-End Ranges of Values for the Site-Average Indoor Air Concentration for 

CWP Fabrication at the Baseline and for the Analytical Options

Case Intermediate (ppm) Low End (ppm) High End (ppm)

Baseline 0.0095 – 0.0181 0.0055 – 0.0092 0.0218 – 0.3934

Phase 1 0.0077 (-18.8%) – 0.0176 (-2.7%) 0.0054 (-3.2%) – 0.0092 (0%) 0.0111 (-49.3%) – 0.3787 (-3.7%)

FSCWPA / Phase 2 0.0072 (-23.5%) – 0.0175 (-3.2%) 0.0053 (-4.0%) – 0.0092 (0%) 0.0084 (-61.5%) – 0.3763 (-4.3%)

NAF 0.0064 (-32.0%) – 0.0110 (-39.3%) 0.0052 (-5.5%) – 0.0092 (0%) 0.0064 (-70.5%) – 0.1807 (-54.1%)

Table ES-2. Estimated Overall Range and Best Estimate for the Site-Average Indoor Air Concentration for CWP Fabrication at the 

Baseline and for the Analytical Options

Case Overall Range (ppm)

Best Estimate

Concentration1(ppm)

Reduction from

Baseline (%)

Baseline 0.0055 – 0.3934 0.1995 --

Phase 1 0.0054 – 0.3787 0.1920 -3.7

FSCWPA / Phase 2 0.0053 – 0.3763 0.1908 -4.3

NAF 0.0052 – 0.1807 0.0930 -53.4

1 The best estimate concentration is the midpoint of the overall range. The overall range is 

defined as the low-end value from the low-end range and the high-end value from the high-end 

range. The reduction from baseline, ADC, and LADC values are calculated from the best 

estimate concentration value.

Table ES-3. Overall Range and Best Estimate ADC for CWP Fabrication at the Baseline and for the Analytical Options

Case Overall Range (μg/m3)

Best Estimate ADC

(μg/m3)

Baseline 1.556 – 110.4 56.0

Phase 1 1.506 – 106.3 53.9

FSCWPA / Phase 2 1.494 – 105.6 53.5

NAF 1.471 – 50.71 26.1
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Table ES-4. Overall Range and Best Estimate LADC for CWP Fabrication at the Baseline and for the Analytical Options

Case Overall Range (μg/m3)

Best Estimate LADC

(μg/m3)

Baseline 0.8894 – 63.08 32.0

Phase 1 0.8607 – 60.72 30.8

FSCWPA / Phase 2 0.8536 – 60.34 30.6

NAF 0.8407 – 28.98 14.9

Table ES-5. Summary of Formaldehyde Indoor Air Concentrations for Office Buildings at the Baseline and for the Analytical

Options

Open Plan Workstations

Case Intermediate (ppm) Low End (ppm) High End (ppm)

Baseline 0.0265 - 0.0732 0.0035 - 0.0053 0.2002 - 1.0089

Phase 1

0.0167 (-37.0%) -

0.0705 (-3.7%) 0.0035 (0%) - 0.0053 (0%) 0.0729 (-63.6%) - 0.2833 (-71.9%)

FSCWPA / 

Phase2

0.0143 (-46.0%) -

0.0701 (-4.2%) 0.0035 (0%) - 0.0053 (0%) 0.0414 (-79.3%) - 0.167 (-83.4%)

NAF 0.0099 (-62.6%) -

0.0346 (-52.7%) 0.0035 (0%) - 0.0053 (0%) 0.0184 (-90.8%) - 0.0728 (-92.8%)

Private Office Workstations

Case Intermediate (ppm) Low End (ppm) High End (ppm)

Baseline 0.013 - 0.0332 0.003 - 0.0036 0.0719 - 0.3555

Phase 1

0.0087 (-33.1%) - 0.032 

(-3.6%) 0.003 (0%) - 0.0036 (0%) 0.0273 (-62.0%) - 0.1011 (-71.6%)

FSCWPA / 

Phase2

0.0077 (-40.8%) -

0.0318 (-4.2%) 0.003 (0%) - 0.0036 (0%) 0.0163 (-77.3%) - 0.0603 (-83.0%)

NAF 0.0058 (-55.4%) -

0.0165 (-50.3%) 0.003 (0%) - 0.0036 (0%) 0.0082 (-88.6%) - 0.0273 (-92.3%)

Note: Values in parentheses are the percent reductions in the indoor air concentration from the baseline value.
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Table ES-6. Summary of Formaldehyde Exposure Concentrations for Office Buildings as Average Daily Concentrations at the 

Baseline and for the Analytical Options

Open Plan Workstations

Case

Intermediate

(μg/m3)

Low End

(μg/m3)

High End

(μg/m3)

Baseline 7.44 - 20.54 0.98 - 1.49 56.17 - 283.1

Phase 1 4.69 - 19.78 0.98 - 1.49 20.46 - 79.49

FSCWPA / 

Phase 2

4.01 - 19.67 0.98 - 1.49 11.62 - 46.86

NAF 2.78 - 9.71 0.98 - 1.49 5.16 - 20.43

Private Office Workstations

Case

Intermediate 

(μg/m3)

Low End 

(μg/m3)

High End 

(μg/m3)

Baseline 3.65 - 9.32 0.84 - 1.01 20.17 - 99.75

Phase 1 2.44 - 8.98 0.84 - 1.01 7.66 - 28.37

FSCWPA / 

Phase 2

2.16 - 8.92 0.84 - 1.01 4.57 - 16.92

NAF 1.63 - 4.63 0.84 - 1.01 2.30 - 7.66
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Table ES-7. Summary of Formaldehyde Exposure Concentrations for Office Buildings as Lifetime Average Daily Concentrations at

the Baseline and for the Analytical Options

Open Plan Workstations

Case

Intermediate

(μg/m3)

Low End

(μg/m3)

High End

(μg/m3)

Baseline 4.25 - 11.74 0.56 - 0.85 32.1 - 161.8

Phase 1 2.68 - 11.3 0.56 - 0.85 11.69 - 45.42

FSCWPA / 

Phase 2

2.29 - 11.24 0.56 - 0.85 6.64 - 26.78

NAF 1.59 - 5.55 0.56 - 0.85 2.95 - 11.67

Private Office Workstations

Case

Intermediate

(μg/m3)

Low End

(μg/m3)

High End

(μg/m3)

Baseline 2.08 - 5.32 0.48 - 0.58 11.53 – 57.00

Phase 1 1.39 - 5.13 0.48 - 0.58 4.38 - 16.21

FSCWPA / 

Phase 2

1.23 - 5.10 0.48 - 0.58 2.61 - 9.67

NAF 0.93 - 2.65 0.48 - 0.58 1.31 - 4.38

Table ES-8. Summary of Best Estimate Results for Office Buildings at the Baseline and for the Analytical Options

Case

Best Estimate

Concentration1

(ppm)

Reduction 

from Baseline 

(%)

ADC 

(μg/m3)

LADC 

(μg/m3)

Baseline 0.0365 -- 10.23 5.85

Phase 1 0.0320 -12.3 8.97 5.13

FSCWPA / 

Phase 2

0.0310 -15.1 8.69 4.97

NAF 0.0167 -54.2 4.69 2.68

1 The best estimate concentration is the average of the following two values: the 

midpoint of the intermediate range for open plan workstations and the midpoint 

of the intermediate range for private office workstations. The reduction from 

baseline, ADC, and LADC values are calculated from the best estimate

concentration value.
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Uncertainties

There is uncertainty in the values of the parameters of the mathematical model for the estimation 

of average indoor air concentration in a CWP fabrication site. In particular, as discussed in

Section 3.3.1.1, there is considerable uncertainty in the range of values for emitting surface area, 

and some uncertainty in the range of values for effective ventilation rate. Therefore, there is 

uncertainty in the calculated range of baseline indoor air concentration. It is not possible to 

determine the direction of uncertainty (i.e., whether the estimated values for indoor air 

concentration are an underestimate or an overestimate). Furthermore, as discussed above, if 

sources other than off-gassing from CWPs are present in a CWP fabrication site, then the 

calculated indoor air concentrations would not be representative of aggregate indoor air 

concentrations.

The composition of composite wood products used in office furniture was not determined and, 

therefore, panels and work surfaces of office workstations were assumed to be entirely composed 

of CWPs. Furthermore, the type and extent of coverage by finishing or overlay materials on the 

CWPs used to fabricate office workstations were also not determined, and a range of values was 

assumed for these parameters. This assumption introduces uncertainty into the calculated indoor 

air concentrations. Furthermore, the mathematical model for the estimation of indoor air 

concentrations in an office building simplifies the complex nature of office building ventilation 

systems. Typically in these systems, outdoor air is mixed with a recirculation stream of indoor 

air prior to being supplied to the various ventilation zones. The return air from these ventilation 

zones is mixed and then a stream is split for recirculation and mixing with the outdoor air while 

the balance is exhausted. Therefore, the office environment model neglects the effect of one 

exposure zone on another resulting from the recirculation of indoor air or the movement of air 

directly between exposure zones without passing through the ventilation system. The 

uncertainty in the results due to neglecting the effect of one exposure zone on another is 

uncertain and cannot be quantified without a detailed, rigorous mathematical model with detailed 

supporting monitoring data. It is not possible to determine the direction of uncertainty in the 

estimated results for indoor air concentration in office buildings.
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Table of Contents

1. INTRODUCTION .................................................................................................................... 1

2. PURPOSE AND SCOPE OF EXPOSURE ASSESSMENT ............................................................... 1

2.1 Manufacturing......................................................................................................... 9

2.2 Composite Wood Product Fabrication.................................................................... 9

2.3 Wholesale.............................................................................................................. 10

2.4 Retail..................................................................................................................... 10

2.5 Commercial Use.................................................................................................... 10

2.6 Disposal and Recycle............................................................................................ 10

3. EXPOSURE ASSESSMENT METHOD ..................................................................................... 11

3.1 Literature Search................................................................................................... 12

3.2 Compilation of Pre-Baseline Exposure Monitoring Data..................................... 13

3.3 Exposure Assessment Methods and Assumptions................................................ 17

3.3.1 Estimation of Indoor Air Concentrations Related to Baseline and 

Analytical Options for CWP Fabrication and Office Buildings............... 18

3.3.1.1 Method for Estimation of Indoor Air Concentration for CWP 

Fabrication ...............................................................................19

3.3.1.2 Method for Estimation of Indoor Air Concentration for Office 

Buildings..................................................................................27

3.3.2 Estimation of Dermal Exposures to Formaldehyde in Liquid Resin ........ 37

4. EXPOSURE ASSESSMENT BY LIFE CYCLE STAGE ............................................................... 37

4.1 Exposure Assessment for Manufacturing ............................................................. 37

4.1.1 Description of Life Cycle Stage................................................................ 37

4.1.2 Production Volumes and Number of Establishments, Workers, 

Production Hours, and Work Days........................................................... 41

4.1.3 Pre-Baseline Exposure Monitoring Data .................................................. 43

4.1.4 Respiratory Protection Usage During Manufacturing .............................. 47

4.1.5 Baseline Exposure and the Effect of Analytical Options on 

Baseline Exposure for Manufacturing ...................................................... 48

4.1.6 Dermal Exposures during Manufacturing................................................. 49

4.2 Exposure Assessment for Composite Wood Product Fabrication ........................ 50

4.2.1 Description of Life Cycle Stage................................................................ 50

4.2.2 Number of Establishments, Workers, Production Hours, and Work 

Days ................................................................................................. 53

4.2.3 Pre-Baseline Exposure Monitoring Data .................................................. 57

4.2.4 Respiratory Protection Usage During Composite Wood Product 

Fabrication ................................................................................................ 57

4.2.5 Baseline Exposure and the Effect of Analytical Options on 

Baseline Exposure for Composite Wood Product Fabrication ................. 59

4.2.5.1 Results for Indoor Air Concentration Calculation Trials and 

Sensitivity Analysis .................................................................59

4.2.5.2 Estimation of a Range of Values for the What-If Low-End and 

the What-If High-End Indoor Air Concentrations that Account 

for All CWP Types ..................................................................60
xiv

4.2.5.3 Final Results for the Estimation of What-If Indoor Air 

Concentrations .........................................................................61

4.2.5.4 The Assessment of Exposure Level for the Baseline and the 

Analytical Options...................................................................63

4.2.6 Dermal Exposures during Composite Wood Product Fabrication............ 69

4.3 Exposure Assessment for Wholesale.................................................................... 69

4.3.1 Description of Life Cycle Stage................................................................ 69

4.3.2 Use Volumes and Number of Establishments, Employees, 

Employed Hours, and Work Days............................................................ 69

4.3.3 Pre-Baseline Exposure Monitoring Data .................................................. 70

4.3.4 Baseline Exposure and the Effect of Analytical Options on 

Baseline Exposure for Wholesale ............................................................. 71

4.3.5 Dermal Exposures during Wholesale........................................................ 71

4.4 Exposure Assessment for Retail ........................................................................... 71

4.4.1 Description of Life Cycle Stage................................................................ 71

4.4.2 Use Volumes and Number of Establishments, Employees, 

Employed Hours, and Work Days............................................................ 72

4.4.3 Pre-Baseline Exposure Monitoring Data .................................................. 73

4.4.4 Baseline Exposure and the Effect of Analytical Options on 

Baseline Exposure for Retail .................................................................... 75

4.4.5 Dermal Exposures during Retail............................................................... 75

4.5 Exposure Assessment for Office Workers during Commercial Use .................... 75

4.5.1 Description of Life Cycle Stage................................................................ 75

4.5.2 Use Volumes and Number of Establishments, Employees, 

Employed Hours, and Work Days............................................................ 75

4.5.3 Pre-Baseline Exposure Monitoring Data .................................................. 76

4.5.4 Baseline Exposure and the Effect of Analytical Options on 

Baseline Exposure for Office Buildings................................................... 77

4.5.4.1 Determination of a Best Estimate for Indoor Air Concentration77

4.5.5 Dermal Exposures during Commercial Use ............................................. 81

5. UNCERTAINTIES IN ASSESSMENT RESULTS........................................................................ 82

5.1 Uncertainties in Assessment Results for Composite Wood Product 

Manufacturing, Fabrication, Wholesale, Retail, and Office Buildings................. 82

5.1.1 Uncertainty in the Estimates of Indoor Air Concentration for 

Composite Wood Product Fabrication...................................................... 82

5.1.2 Uncertainty in the Estimates of Indoor Air Concentration for 

Office Buildings........................................................................................ 83

5.2 Uncertainties in Pre-Baseline Monitoring Data.................................................... 84

5.2.1 OSHA IMIS Data...................................................................................... 84

5.2.2 BASE Study Monitoring Data .................................................................. 92

5.3 Uncertainty in Number of Production Workers and Employees.......................... 93

6. REFERENCES ...................................................................................................................... 94

Appendix A: Definition of Terms

Appendix B: Data Quality Acceptance Criteria Specifications
xv

Appendix C: Existing Formaldehyde Occupational Exposure Limits and Formaldehyde OffGassing Emission Standards for Composite Wood Products

Appendix D: Formaldehyde CWP Off-Gassing Emission Level Data for the Pre-Baseline Period, 

Baseline, and the Analytical Options

Appendix E: Modeling Methodology for Estimating Indoor Air Concentrations Related to 

Baseline and Analytical Options

Appendix F: Pre-Baseline Formaldehyde Exposures from OSHA IMIS by Worker Activity and 

Industry Sector for Composite Wood Product Fabricators

Appendix G: Summary of OSHA Inspection Reports

Appendix H: Summary of Additional Exposure Monitoring Data from Manufacturing

Appendix I: Model Results for Indoor Air Concentrations at CWP Fabrications Sites using PreBaseline Emission Rates
xvi

List of Tables

TABLE ES-1. ESTIMATED LOW-END, INTERMEDIATE, AND HIGH-END RANGES OF VALUES 

FOR THE SITE-AVERAGE INDOOR AIR CONCENTRATION FOR CWP FABRICATION AT 

THE BASELINE AND FOR THE ANALYTICAL OPTIONS.........................................................VIII

TABLE ES-2. ESTIMATED OVERALL RANGE AND BEST ESTIMATE FOR THE SITE-AVERAGE 

INDOOR AIR CONCENTRATION FOR CWP FABRICATION AT THE BASELINE AND FOR 

THE ANALYTICAL OPTIONS...............................................................................................VIII

TABLE ES-3. OVERALL RANGE AND BEST ESTIMATE ADC FOR CWP FABRICATION AT THE 

BASELINE AND FOR THE ANALYTICAL OPTIONS................................................................VIII

TABLE ES-4. OVERALL RANGE AND BEST ESTIMATE LADC FOR CWP FABRICATION AT 

THE BASELINE AND FOR THE ANALYTICAL OPTIONS...........................................................IX

TABLE ES-5. SUMMARY OF FORMALDEHYDE INDOOR AIR CONCENTRATIONS FOR OFFICE 

BUILDINGS AT THE BASELINE AND FOR THE ANALYTICAL OPTIONS ...................................IX

TABLE ES-6. SUMMARY OF FORMALDEHYDE EXPOSURE CONCENTRATIONS FOR OFFICE 

BUILDINGS AS AVERAGE DAILY CONCENTRATIONS AT THE BASELINE AND FOR THE 

ANALYTICAL OPTIONS......................................................................................................... X

TABLE ES-7. SUMMARY OF FORMALDEHYDE EXPOSURE CONCENTRATIONS FOR OFFICE 

BUILDINGS AS LIFETIME AVERAGE DAILY CONCENTRATIONS AT THE BASELINE 

AND FOR THE ANALYTICAL OPTIONS ..................................................................................XI

TABLE ES-8. SUMMARY OF BEST ESTIMATE RESULTS FOR OFFICE BUILDINGS AT THE 

BASELINE AND FOR THE ANALYTICAL OPTIONS..................................................................XI

TABLE 2-1. NAICS INDUSTRY SECTORS IDENTIFIED FOR THE LIFE CYCLE STAGES OF 

HWPW, MDF, AND PB....................................................................................................... 6

TABLE 3-1. PRE-BASELINE FORMALDEHYDE EMISSION LEVELS FOR DOMESTICALLYPRODUCED COMPOSITE WOOD PRODUCTS ........................................................................ 15

TABLE 3-2. SUMMARY OF WHAT-IF METHOD FOR THE ESTIMATION OF THE WHAT-IF 

RANGE OF AVERAGE INDOOR AIR CONCENTRATIONS OF FORMALDEHYDE AT CWP

FABRICATION SITES ........................................................................................................... 21

TABLE 3-3. MATRIX OF VENTILATION RATES AND MIXING FACTORS ........................................... 22

TABLE 3-4. ESTIMATED VALUES FOR PARAMETERS IN THE MATHEMATICAL MODEL FOR 

AVERAGE INDOOR AIR CONCENTRATION AT A CWP FABRICATION SITE FOR THE 

BASELINE AND THE ANALYTICAL OPTIONS........................................................................ 26

TABLE 3-5. DATA SOURCES FOR THE ESTIMATION OF PARAMETERS OF THE 

MATHEMATICAL MODEL FOR AVERAGE INDOOR AIR CONCENTRATION AT A CWP

FABRICATION SITE............................................................................................................. 27
xvii

TABLE 3-6. SUMMARY OF WHAT-IF METHOD FOR THE ESTIMATION OF THE WHAT-IF 

RANGE OF AVERAGE INDOOR AIR CONCENTRATIONS OF FORMALDEHYDE IN 

WORKSTATION VOLUMES.................................................................................................. 30

TABLE 3-7. COMPARISON OF ASTM E1333 PARAMETER VALUES WITH TYPICAL OFFICE 

ENVIRONMENT PROPERTIES............................................................................................... 33

TABLE 3-8. ESTIMATED VALUES FOR PARAMETERS IN THE MATHEMATICAL MODEL FOR 

AVERAGE INDOOR AIR CONCENTRATION RESULTING FROM EMISSIONS FROM 

PRIVATE OFFICE AND OPEN PLAN WORKSTATIONS FOR THE BASELINE AND 

ANALYTICAL OPTIONS....................................................................................................... 34

TABLE 4-1. U.S. HARDWOOD PLYWOOD PRODUCTION DATA AND NUMBER OF MILLS ................ 42

TABLE 4-2. U.S. RECONSTITUTED WOOD PRODUCT PRODUCTION DATA AND NUMBER OF 

MILLS ................................................................................................................................ 43

TABLE 4-3. SUMMARY OF 2007 ECONOMIC CENSUS DATA AND EXPOSURE FREQUENCY 

AND DURATION CALCULATED FROM THESE DATA FOR U.S. MANUFACTURING 

MILLS ................................................................................................................................ 43

TABLE 4-4. SUMMARY OF FORMALDEHYDE INHALATION MONITORING DATA FOR 

HARDWOOD PLYWOOD MANUFACTURING MILLS FROM THE OSHA IMIS

DATABASE ......................................................................................................................... 44

TABLE 4-5. SUMMARY OF FORMALDEHYDE INHALATION MONITORING DATA FOR 

RECONSTITUTED WOOD PRODUCT MANUFACTURING MILLS FROM THE OSHA IMIS

DATABASE ......................................................................................................................... 45

TABLE 4-6. SUMMARY OF 2007 ECONOMIC CENSUS DATA AND EXPOSURE FREQUENCY 

AND DURATION CALCULATED FROM THESE DATA FOR COMPOSITE WOOD 

PRODUCT FABRICATING SITES ........................................................................................... 54

TABLE 4-7. SUMMARY OF ALL IMIS TWA PERSONAL MONITORING DATA FOR 

INDUSTRIES WITHIN THE CWP FABRICATOR LIFE CYCLE STAGE...................................... 57

TABLE 4-8. RESULTS FOR THE CALCULATION TRIALS FOR THE WHAT-IF LOW- AND HIGHEND BASELINE INDOOR AIR CONCENTRATIONS................................................................. 64

TABLE 4-9. RESULTS FOR THE CALCULATION TRIALS FOR THE WHAT-IF LOW- AND HIGHEND CARB PHASE 1 INDOOR AIR CONCENTRATIONS ....................................................... 65

TABLE 4-10. RESULTS FOR THE CALCULATION TRIALS FOR THE WHAT-IF LOW- AND HIGHEND FSCWPA / CARB PHASE 2 INDOOR AIR CONCENTRATIONS..................................... 66

TABLE 4-11. RESULTS FOR THE CALCULATION TRIALS FOR THE WHAT-IF LOW- AND HIGHEND NAF INDOOR AIR CONCENTRATIONS ........................................................................ 67
xviii

TABLE 4-12. ESTIMATED LOW-END, INTERMEDIATE, AND HIGH-END RANGES OF VALUES 

FOR THE SITE-AVERAGE INDOOR AIR CONCENTRATION AT THE BASELINE AND FOR 

THE ANALYTICAL OPTIONS................................................................................................ 67

TABLE 4-13. ESTIMATED OVERALL RANGE AND BEST ESTIMATE SITE-AVERAGE INDOOR 

AIR CONCENTRATION AT THE BASELINE AND FOR THE ANALYTICAL OPTIONS ................. 68

TABLE 4-14. OVERALL RANGE AND BEST ESTIMATE ADC AT THE BASELINE AND FOR THE 

ANALYTICAL OPTIONS....................................................................................................... 68

TABLE 4-15. OVERALL RANGE AND BEST ESTIMATE LADC AT THE BASELINE AND FOR THE 

ANALYTICAL OPTIONS....................................................................................................... 68

TABLE 4-16. SUMMARY OF 2007 ECONOMIC CENSUS DATA FOR WHOLESALE FACILITIES........... 70

TABLE 4-17. SUMMARY OF FORMALDEHYDE INHALATION MONITORING DATA FOR 

WHOLESALERS FROM THE OSHA IMIS DATABASE........................................................... 71

TABLE 4-18. SUMMARY OF 2007 ECONOMIC CENSUS DATA FOR RETAIL FACILITIES ................... 73

TABLE 4-19. SUMMARY OF FORMALDEHYDE INHALATION MONITORING DATA FOR 

RETAILERS FROM THE OSHA IMIS DATABASE ................................................................. 74

TABLE 4-20. OVERVIEW OF GENERAL CHARACTERISTICS OF THE 100 BASE BUILDINGS ............ 76

TABLE 4-21. SUMMARY OF FORMALDEHYDE INHALATION MONITORING DATA FOR OFFICE 

OCCUPATIONAL SETTINGS AND OUTDOOR MEASURED CONCENTRATIONS FROM THE 

BASE STUDY .................................................................................................................... 76

TABLE 4-22. RESULTS FOR CALCULATION OF WHAT-IF INDOOR AIR FORMALDEHYDE 

CONCENTRATIONS FOR EACH ANALYTICAL OPTION.......................................................... 79

TABLE 4-23. COMBINED (FOR ALL CWP) RESULTS: CALCULATED WHAT-IF INDOOR AIR 

CONCENTRATIONS AT THE BASELINE AND FOR THE ANALYTICAL OPTIONS....................... 80

TABLE 4-24. COMBINED (FOR ALL CWP) RESULTS: CALCULATED WHAT-IF INDOOR AIR 

ADCS AT THE BASELINE AND FOR THE ANALYTICAL OPTIONS.......................................... 80

TABLE 4-25. COMBINED (FOR ALL CWP) RESULTS: CALCULATED WHAT-IF INDOOR AIR 

LADCS AT THE BASELINE AND FOR THE ANALYTICAL OPTIONS ....................................... 81

TABLE 4-26. BEST ESTIMATE OF WHAT-IF FORMALDEHYDE EXPOSURE CONCENTRATION 

AT THE BASELINE AND FOR THE ANALYTICAL OPTIONS..................................................... 81

TABLE 5-1. NUMBER OF OSHA INSPECTIONS AT CWP FABRICATION FACILITIES 

COMPARED TO THE MAXIMUM NUMBER OF FACILITIES FROM THE U.S. ECONOMIC 

CENSUS.............................................................................................................................. 85
xix

List of Figures

FIGURE 2-1. LIFE CYCLE AND MARKET DISTRIBUTION OF HWPW ................................................. 3

FIGURE 2-2. LIFE CYCLE AND MARKET DISTRIBUTION OF MDF..................................................... 4

FIGURE 2-3. LIFE CYCLE AND MARKET DISTRIBUTION OF PB ........................................................ 5

FIGURE 4-1. COMPARISON OF MODEL RESULTS FOR RANGES OF WHAT-IF INDOOR AIR 

CONCENTRATIONS USING PRE-BASELINE EMISSION RATES WITH OSHA IMIS DATA....... 62

FIGURE 5-1. TWA EXPOSURES FROM OSHA IMIS FOR A SINGLE INSPECTION FOR 

ARMSTRONG CABINETS (NAICS 337110)......................................................................... 88

FIGURE 5-2. TWA EXPOSURES FROM OSHA IMIS FOR A SINGLE INSPECTION FOR MID 

CONTINENT CABINETRY (NAICS 337110)........................................................................ 88

FIGURE 5-3. TWA EXPOSURES FROM OSHA IMIS FOR A SINGLE INSPECTION FOR 

BENVENUTI AND STEIN (NAICS 337122).......................................................................... 89

FIGURE 5-4. TWA EXPOSURES FROM OSHA IMIS FOR A SINGLE INSPECTION FOR 

AMERIWOOD INDUSTRIES (NAICS 337122)...................................................................... 89

FIGURE 5-5. TWA EXPOSURES FROM OSHA IMIS FOR TWO INSPECTIONS FOR THE 

GUNLOCKE COMPANY (NAICS 337211)........................................................................... 90

FIGURE 5-6. TWA EXPOSURES FROM OSHA IMIS FOR TWO INSPECTIONS FOR SILVER 

STREET (NAICS 337211) .................................................................................................. 90

FIGURE 5-7. TWA EXPOSURES FROM OSHA IMIS FOR A SINGLE INSPECTION FOR THE 

COMMERCIAL FURNITURE GROUP (NAICS 337127)......................................................... 91
xx

List of Abbreviations

ADC Average daily concentration

C&D Construction and demolition

CARB P1 California Air Resources Board Formaldehyde Regulation Phase 1

CARB P2 California Air Resources Board Formaldehyde Regulation Phase 2

CFM Cubic feet per minute

CWP Composite wood product

FSCWPA Formaldehyde Standards for Composite Wood Products Act

HWPW Hardwood plywood

HWPW-CC Hardwood plywood – composite core

HWPW-VC Hardwood plywood – veneer core

LADC Lifetime average daily concentration

MDF Medium-density fiberboard

MF Melamine formaldehyde

MSW Municipal solid waste

NAF No-added formaldehyde

OSHA Occupational Safety and Health Administration

PB Particleboard

PF Phenol formaldehyde

pMDI Poly(methylene diphenyl diisocyanate)

PPE Personal protective equipment

PVA Poly(vinyl acetate)

tMDF Thin medium-density fiberboard

TWA Time-weighted average

UF Urea formaldehyde

ULEF Ultra low emitting formaldehyde
Formaldehyde Occupational Exposure Assessment Report – Draft Final Report

October 6, 2011

Page 1

1. INTRODUCTION

In March 2008, the Environmental Protection Agency (EPA) was petitioned by the Sierra Club 

and other signatories under Section 21 of the Toxic Substances Control Act (TSCA) to adopt 

nationally an Airborne Toxic Control Measure (ATCM) promulgated by the California Air 

Resources Board (CARB) in 2008 that establishes maximum formaldehyde emissions from the 

three types of composite wood products: hardwood plywood (HWPW), medium-density

fiberboard (MDF), and particleboard (PB). As described in EPA’s Advance Notice of Proposed 

Rulemaking (ANPR) published in December 2008 (73 FR 73620) and in response to this 

petition, EPA investigated whether regulatory action, including possible action under TSCA 

Section 6, or non-regulatory action might be appropriate to control the levels of formaldehyde 

emitted from composite wood products.

In July 2010, President Obama signed into law the Formaldehyde Standards for Composite 

Wood Products Act (FSCWPA).1 This law is an amendment to TSCA and directs EPA to 

regulate the formaldehyde emissions from HWPW, MDF, and PB. FSCWPA sets formaldehyde 

limits equal to the CARB ATCM standards. It also requires EPA to promulgate implementing 

regulations by January 1, 2013. As part of the development of a rule under FSCWPA, EPA is 

conducting a cost-benefit analysis of implementing the formaldehyde limits cited by FSCWPA. 

In support of this cost-benefit analysis, EPA assessed occupational inhalation and dermal

exposure to formaldehyde during the life cycle of HWPW, PB, and MDF.

2. PURPOSE AND SCOPE OF EXPOSURE ASSESSMENT

The purpose of the assessment is, first, the prediction of baseline formaldehyde inhalation and 

dermal occupational exposure that is due to all sources of exposure (aggregate exposure) during 

the life cycle of composite wood products (CWPs), and, second, the determination of the effect

on baseline exposure of the analytical options for limits on emission levels for off-gassing from 

HWPW, PB, and MDF.

The baseline occurs in the year in which EPA will promulgate limits under FSCWPA, which will 

be 2013. This document discusses various analytical options for limits on emission levels for 

off-gassing from HWPW, PB, and MDF (i.e., various emission standards) simply for 

informational purposes. The breadth of the discussion here should not imply that EPA 

necessarily has corresponding flexibility in implementing the statute. The following specific 

analytical options were assessed in support of the cost-benefit analysis for the formaldehyde 

rulemaking activity:

 Analytical Option 1: a scenario in which EPA would implement maximum 

formaldehyde emission limits equal to the CARB ATCM Phase 1 limits;

 Analytical Option 2: a scenario in which EPA would implement maximum 

formaldehyde emission limits equal to the CARB ATCM Phase 2 limits (which 

are equal to the limits specified in FSCWPA); and

 

1 TSCA §§ 601 et seq. (15 U.S.C. §§ 2697 et seq.), http://www.gpo.gov/fdsys/pkg/PLAW-111publ199/pdf/PLAW111publ199.pdf
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October 6, 2011

Page 2

 Analytical Option 3: a scenario in which EPA would implement maximum 

formaldehyde emission limits equal to the no-added formaldehyde (NAF) limits 

specified in FSCWPA.

Figure 2-1, Figure 2-2, and Figure 2-3 depict the life cycle and market distribution for HWPW, 

MDF, and PB, respectively. Manufacture, import, and export volumes are expressed in cubic 

meters of composite wood products and are annual volumes for the year 2005 (Table 2-5 of 

USEPA 2010a). Market distributions are expressed as percentages that represent the amounts of 

North American produced CWP that are sold to the various CWP fabrication industry sectors and 

directly to retail (section 2.3.2 of USEPA 2010a). The market distributions of imports are 

unknown. Percentages may not sum to 100 percent due to rounding. The description of the life 

cycles, i.e., the markets and market channels, were obtained from the Hardwood Plywood and 

Veneer Association (HPVA) (for HWPW) and the Composite Panel Association (CPA) (for PB 

and MDF) (HPVA 2009a; CPA 2008a).

This assessment assesses potential worker exposure to formaldehyde from the following life

cycle stages of HWPW, PB and MDF:

 Manufacture of HWPW, PB and MDF within the United States (domestic 

manufacturing);

 Downstream manufacture of products constructed from domestically

manufactured and imported HWPW, PB and MDF (e.g. manufacture of furniture 

using HWPW, PB and MDF), referred to in this report as composite wood 

product fabrication;

 Wholesale and retail of domestically manufactured and imported HWPW, PB, 

MDF, and downstream products fabricated from these CWPs; and

 Occupancy by office workers of office buildings containing domestically 

manufactured and imported HWPW, PB, MDF, and downstream products 

fabricated from these CWPs.

The life cycle stages not assessed due to major data gaps include the following:

 Commercial construction using HWPW, PB, MDF, and products fabricated from 

these CWPs; and

 Recycling and disposal of HWPW, PB, MDF, and products fabricated from these 

CWPs.

The life cycle stages that are assessed as well as those that were not assessed are further 

discussed below in Sections 2.1 through 2.6. Table 2-1 summarizes the applicable NAICS codes 

for the assessed life cycle stages.
Formaldehyde Occupational Exposure Assessment Report – Draft Final Report

October 6, 2011

Page 3

Figure 2-1. Life Cycle and Market Distribution of HWPW

HWPW 

Manufacturing

1,844,000

Distributors 

(Wholesale)

Direct Sale

Cabinets

Furniture

Fixtures

Retail

Engineered Wood 

Flooring

Wholesale

Commercial 

and 

Consumer 

Use

Municipal 

Solid Waste

(MSW)

Recycle

HWPW 

Import

4,020,311

Manufacture 

and Import (1)

Market Channel (2) CWP Fabrication (3) Wholesale and 

Retail (5)

Commercial and 

Consumer Use (4)

Disposal and 

Recycle (5)

HWPW 

Export

243,763

Figure notes: 

1. Market volumes are in cubic meters. 

2. According to information from HPVA, HWPW is distributed from the manufacturer or importer to CWP fabricators

through multiple market channels. In some cases, HWPW panels can be sold to retail for direct consumption. The 

EPA market profile reports that about 70% of total sales by U.S. HWPW manufacturers are to wholesale distributors.

3. The EPA market profile reports that approximately two-thirds of North American HWPW production is for panels. 

Panels are sold to cabinet manufacturers, retail building materials dealers, furniture manufacturers, and fixture 

manufacturers.

4. Consumer use is not within the scope of this assessment.

5. Market volumes are not available for wholesale, retail, disposal, and recycle.

Construction 

and Demolition 

(C&D) Debris

Landfills
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October 6, 2011

Page 4

Figure 2-2. Life Cycle and Market Distribution of MDF

MDF 

Manufacturing

3,256,912

Distributors 

(Wholesale)

Retail

Direct Sale

Overlay Material 

Applicators

Kitchen and Bath,

including Counter Tops

Other

Household Furniture

Office Furniture

Door Components

Retail

Shelving

Laminate Flooring

Electronic Cabinets

Moulding and Millwork

Wholesale

Commercial and 

Consumer Use

Municipal Solid 

Waste (MSW)

Recycle

12%

17%

2%

3%

6%

1%

13%

1%

23%

Store Fixtures

4%

MDF Import

966,967

MDF Export

163,889

Manufacture 

and Import

Market Channel CWP Fabrication Wholesale and 

Retail

Commercial and 

Consumer Use (4)

Disposal and 

Recycle

15%

Figure notes: 

1. Market volumes are in cubic meters.

2. According to information from CPA, MDF is distributed 

from the primary manufacturer or importer to CWP 

fabricators through multiple market channels. In some 

cases, composite wood can be sold directly to retail for 

direct consumption.

3. Market volumes are not available for wholesale, retail, 

disposal, and recycle.

4. Consumer use is not within the scope of this assessment.

Prefinished Paneling

Mobile Home Decking and 

Underlayment

<0.4%

4%

Construction and 

Demolition 

(C&D) Debris 

Landfills
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October 6, 2011

Page 5

Figure 2-3. Life Cycle and Market Distribution of PB

PB 

Manufacturing

7,275,399

Distributors 

(Wholesale)

Retail

Direct Sale

Overlay 

Material 

Applicators

Retail

Shelving

Flooring, including mobile 

home decking

Electronic Cabinets

Moulding and Millwork

Wholesale

Commercial and 

Consumer Use

Municipal Solid 

Waste (MSW)

Recycle

1%

4%

<2.4%

0.2%

<2.2%

4% Store Fixtures

PB Import

1,346,903

Kitchen and Bath, including

counter tops

36%

6%

Door Components

12% Other

10% Office Furniture

21% Household Furniture

PB Export

258,827

Manufacture 

and Import

Market Channel CWP Fabrication Wholesale and 

Retail

Commercial and 

Consumer Use (4)

Disposal and 

Recycle

Figure notes: 

1. Market volumes are in cubic meters.

2. According to information from CPA, PB is distributed from 

the primary manufacturer or importer to CWP fabricators

through multiple market channels. In some cases, composite 

wood can be sold directly to retail for direct consumption.

3. Market volumes are not available for wholesale, retail, 

disposal, and recycle.

4. Consumer use is not within the scope of this assessment.

Underlayment

3%

Prefinished Paneling

2%

Construction and 

Demolition 

(C&D) Debris 

Landfills
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October 6, 2011

Page 6

Table 2-1. NAICS Industry Sectors Identified for the Life Cycle Stages of HWPW, MDF, 

and PB

Life Cycle Stage Included NAICS Codes Corresponding NAICS Industry Descriptions

HWPW Manufacturing 321211 Hardwood veneer & plywood manufacturing

MDF Manufacturing 321219 Reconstituted wood product manufacturing PB Manufacturing

Composite Wood Product Fabrication

321911 Wood window & door manufacturing

321918 Other millwork (including flooring)

321991 Manufactured home (mobile home) 

manufacturing

321999 All Other Miscellaneous Wood Product 

Manufacturing

336213 Motor Home Manufacturing

336214 Travel Trailer & Camper Manufacturing

337110 Wood kitchen cabinet & counter top 

manufacturing

337121 Upholstered household furniture manufacturing

337122 Non-upholstered wood household furniture 

manufacturing

337124 Metal Household Furniture Manufacturing

337127 Institutional furniture manufacturing

337129 Wood television, radio, & sewing machine 

cabinet manufacturing

337211 Wood office furniture manufacturing

337212 Custom architectural woodwork & millwork 

manufacturing

337214 Office Furniture (except Wood) Manufacturing

337215 Showcase, partition, shelving, & locker 

manufacturing

339950 Sign Manufacturing

Wholesale

423210 Furniture merchant wholesaler

423220 Home furnishing merchant wholesaler

423310 Lumber, plywood, & wood panel merchant 

wholesaler

423320 Brick, stone, & construction material merchant 

wholesaler

423330 Roofing, siding, & insulation material merchant 

wholesaler

423390 Other construction material merchant 

wholesaler

423440 Other commercial equipment merchant 

wholesalers

423450 Medical, dental, & hospital equipment & 

supplies merchant wholesalers

423490 Other professional equipment & supplies 

merchant wholesaler

423510 Metal service centers and other metal merchant 

wholesalers

423610 Elec. equip. and wiring merchant wholesalers

423620 Electric appliance, TV & radio merchant 

wholesalers

423710 Hardware merchant wholesalers
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Table 2-1 Continued

Life Cycle Stage Included NAICS Codes Corresponding NAICS Industry Descriptions

423720 Plumbing equip. merchant wholesalers

423730 HVAC equip. merchant wholesalers

423740 Refrigeration equipment and supplies merchant 

wholesalers

423830 Industrial machinery & equipment merchant 

wholesalers

423850 Service establishment equipment & supp 

merchant wholesalers

423910 Sporting & recreational goods & supplies 

merchant wholesalers

424610 Plastics materials and basic forms and shapes 

merchant wholesaler

424950 Paint, varnish, and supplies merchant 

wholesalers

Retail

441210 Recreational vehicle dealers

442110 Furniture stores

442210 Floor covering stores

442291 Window treatment stores

442299 All other home furnishings stores

443111 Household appliance stores

443112 Radio, television, & other electronics stores

443120 Computer & software stores

444110 Home centers

444120 Paint and wallpaper stores

444130 Hardware stores

444190 Other building material dealers

444210 Outdoor power equipment stores

444220 Nursery, garden center, & farm supply stores

445110 Supermarkets and other grocery (except 

convenience) stores

448110 Men's clothing stores

448120 Women's clothing stores

448130 Children's and infants' clothing stores

448140 Family clothing stores

448150 Clothing accessories stores

448190 Other clothing stores

451120 Hobby, toy, and game stores

451130 Sewing, needlework, and piece goods stores

452111 Department stores (except discount department 

stores)

452112 Discount department stores

452910 Warehouse clubs and supercenters

452990 All other general merchandise stores

453110 Florists

453210 Office supplies and stationery stores

453220 Gift, novelty, and souvenir stores

453920 Art dealers

453930 Manufactured (mobile) home dealers
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Table 2-1 Continued

Life Cycle Stage Included NAICS Codes Corresponding NAICS Industry Descriptions

453998 All other miscellaneous store retailers (except 

tobacco stores)

454113 Mail-order houses

454390 Other direct selling establishments

Source: EPA market profile (USEPA 2010a)
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page 9

2.1 Manufacturing

The term “manufacturing” in this report refers specifically to the manufacture of HWPW, MDF, 

and PB (and is also referred to as “primary manufacturing”). The scope of this assessment

includes the domestic manufacture of these products themselves but excludes any part of the 

upstream supply chain for the manufacture of these products such as resin or veneer

manufacturing. Occupational exposures of formaldehyde in UF resin manufacture is covered 

under the “Draft Final Occupational Exposure and Environmental Release Assessment of 

Formaldehyde in Urea-Formaldehyde Resin Manufacture and of Substitute Technologies to 

Reduce Emissions from Composite Wood Products” (USEPA 2011a). The manufacture of 

imports, i.e., the manufacture of HWPW, MDF, and PB in countries outside of the U.S., is not 

included in the scope of this assessment.

The NAICS code 321219 - Reconstituted Wood Product Manufacturing includes both the 

manufacture of PB and MDF. It also includes the manufacture of composite wood products not 

included in the scope of this assessment, such as hardboard, oriented strandboard, and 

waferboard (Census 2007a).

The NAICS code 321211 - Hardwood Veneer and Plywood Manufacturing includes the 

manufacture of hardwood plywood. It also includes the manufacture of hardwood veneer

(Census 2007a). These veneers are typically not manufactured at the same facilities that 

manufacture hardwood plywood. Therefore, hardwood veneer manufacturing facilities would 

not be subject to any requirements under the proposed FSCWPA rule (USEPA 2010a). 

Therefore, hardwood veneer manufacturing facilities are not included in the scope of this 

assessment.

2.2 Composite Wood Product Fabrication

HWPW, MDF, and PB may be converted into articles or other products. For example, HWPW 

may be pressed into panels and plywood components (e.g., curved HWPW, seat backs, chair 

arms, etc.) or used for furniture, cabinets, architectural millwork, paneling for commercial 

buildings, flooring, store fixtures and doors (OAQPS 2000b). Similarly, MDF and PB are used 

in the manufacture of many products including virtually every application where interior panels 

or strips are required, especially in furniture and cabinetry. However, MDF is not used as floor 

underlayment or decking except on special request (Kirk-Othmer 2011a). In addition to furniture 

and cabinetry, PB is used as floor decking in manufactured homes, underlayment in conventional 

homes, shelving, countertops, door cores, stair stepping, door frames, and many other products

that require small flat parts as a starting point. A small portion of PB is also extruded or molded 

into furniture parts, paper roll plugs, brush bases and toilet seats (Kirk-Othmer 2011a).

Composite wood products also may have “value-added surfaces” added to the panel product. 

“Value-added surfaces” include decorative finishes or overlays and coatings, which may be 

applied at a “sister” facility of the manufacturer or at unaffiliated finishing sites (CPA 2007a;

CPA 2009a). A technical bulletin published by the Composite Panel Association (CPA) further 

discusses the types of value-added surfaces (CPA 2007a).
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2.3 Wholesale

Wholesalers buy products from manufacturers in bulk for the purpose of resale to various 

industries and individuals. Wholesale products may include CWP fabrication products as well as 

composite wood products (i.e., panels). A single wholesaler may sell many different types of 

composite wood products (Census 2007a).

2.4 Retail

Retailers operate from fixed locations and sell products for direct consumption by the purchaser 

(individuals or businesses). These retailers may receive HWPW, MDF, or PB directly or as 

components in CWP fabrication products. Like the wholesale sector, the retail sector is not 

distinguished by composite wood product type (Census 2007a).

2.5 Commercial Use

The commercial use of composite wood products includes (1) the use of composite wood

products in on-site construction, and (2) the occupancy by office workers of workplace buildings 

(commercial buildings) containing composite wood products. CWP fabrication products such as 

furniture and cabinets, in addition to composite wood products, are present in commercial 

buildings.

Data gaps for on-site construction using HWPW, PB, and MDF include the following:

 The volumes of HWPW, PB, and MDF used during on-site construction could not 

be determined.

 The number of sites and workers engaged in on-site construction could not be 

determined. Therefore, the size of this life cycle stage and the number of workers 

exposed during this life cycle stage are unknown.

 Formaldehyde monitoring data for on-site construction could not be determined. 

Therefore, the range of potential exposures that occur during this life cycle stage 

is unknown.

Due to these data gaps, this assessment does not include an occupational exposure assessment of 

formaldehyde during on-site construction.

2.6 Disposal and Recycle

At end of life, composite wood is either disposed of as municipal solid wastes (MSW) or 

construction and demolition (C&D) debris materials, or recycled into new products.

A total of 15.84 million tons of wood MSW was generated (before recycling) in 2009 in the U.S. 

Of these 15.84 million tons, 10.08 million tons were from wood pallets and wood crates (USEPA 

2010b). Wood pallets and wood crates are likely not constructed of CWPs and are outside the 

scope of this assessment. Of these 15.84 million tons of wood MSW, the remaining 5.76 million 

tons of wood were from furniture and furnishings (USEPA 2010b). As discussed in this report, 

CWPs are used in the fabrication of furniture; therefore, an unknown fraction of the 5.76 million 

tons of wood likely consists of CWPs. EPA reports that the only identified recovery of materials 
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from MSW composed of furniture and furnishings was mattress recovery (USEPA 2010b). Of 

all MSW discarded in 2009 (after recovery for recycling and composting), 82% was landfilled or 

otherwise disposed and 18% was incinerated for energy recovery (USEPA 2010b). Therefore, it 

is likely that CWPs in furniture that enters the MSW stream are not recovered and are discarded 

via landfilling or incineration.

C&D materials consist of the debris generated during the construction, renovation, and

demolition of buildings, roads, and bridges, which can include wood materials (USEPA 2011c). 

The majority of building-related C&D materials come from building demolition and renovation 

with the remainder from new construction (USEPA 2011c). A report from 2003 estimated that 

20% to 30% of building related C&D debris generated was wood (USEPA 2011c). However, it 

is unknown what fraction of wood C&D debris consists of CWPs.

In 1995, the Department of Agriculture estimated that 3.96 million tons2of wood products were 

recovered for recycling into miscellaneous uses (USDA 1996a). The sources and types of the 

recovered wood products referred to here were not given, and it is unknown whether the 

recovered wood material includes CWPs. The term “miscellaneous uses” was not explicitly

defined in the text but referred to examples such as insulation, molded pulp products, hardboard, 

insulating paperboard, and composite wood panels. More recently, of the 10.08 million tons of 

wood MSW from wood pallets and wood crates, 22% were recovered for recycling as mulch and 

bedding material (USEPA 2011b); however, as stated above, wood pallets and wood crates are 

likely not constructed of CWPs. Several existing and developing technologies exist for 

producing composites using recycled wood-based fiber. These composites include dry-formed 

wood composites, wet-formed structural fiber products, wood-plastic composites, and woodinorganic composites (Hamilton 1996a).

Data gaps for the disposal and recycling of HWPW, PB, and MDF include the following:

 The volumes of HWPW, PB, and MDF disposed of as waste and recycled could 

not be determined.

 Formaldehyde monitoring data for the disposal and recycling of composite wood

products could not be determined.

Due to these uncertainties, this assessment does not include an occupational exposure assessment 

of formaldehyde during disposal and recycling. It is noted that due to the decay of formaldehyde 

emission rates from CWPs with time (see Section 3.3.1.1), CWPs can have reduced emission 

rates and, therefore, a diminished contribution to exposure concentrations when disposed or 

recycled at their end of life.

3. EXPOSURE ASSESSMENT METHOD

This section describes the data collection efforts and the methods used for assessing occupational 

exposures, and their underlying assumptions.

 

2

3.96 million U.S. tons or 3.6 million metric tonnes.
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3.1 Literature Search

This exposure assessment relied on the use of readily available data, including exposure 

monitoring data and mathematical modeling data. A comprehensive literature search of readily 

available government, industry, and academic sources was conducted, which included sources 

from EPA, OSHA, NIOSH, the California Air Resources Board (CARB), SRI International, and 

the Organization for Economic Co-operation and Development (OECD), as well as industry

websites, academic journals, and other publications. Additionally, submissions in response to 

EPA’s ANPR (73 FR 73620) were reviewed. The ANPR review included 123 public 

submissions to Docket Number EPA-HQ-OPPT-2008-0627 and 30 public submissions to Docket 

Number EPA-HQ-OPPT-2008-0267. Also reviewed were regulations, such as the National 

Emissions Standards for Hazardous Air Pollutants (NESHAP) for plywood and composite wood 

products and the Housing and Urban Development (HUD) Rule on formaldehyde emissions from 

certain wood products in manufactured homes (24 CFR § 3280.308).

The following specific databases and studies were searched for formaldehyde air monitoring 

data:

 OSHA’s Integrated Management Information System (IMIS);

 EPA’s Building Assessment Survey and Evaluation (BASE) study;

 The Relationship of Indoor, Outdoor, and Personal Air (RIOPA) project; 

 The International Agency for Research into Cancer (IARC) Formaldehyde 

Monograph (Volume 88); and

 The Detroit Exposure and Aerosol Research Study (DEARS).

The literature search did not yield any formaldehyde air monitoring data that are directly relevant 

to this exposure assessment. Data from OSHA IMIS and EPA’s BASE study were the most 

relevant data obtained and were used in this assessment to provide perspective as discussed in

Section 3.2. Additionally, other exposure monitoring studies of CWP manufacturers from the 

literature are cited in this assessment, but data from OSHA IMIS are more comprehensive and 

more relevant to this exposure assessment than these additional studies as OSHA IMIS contains 

only U.S. data. A summary of the abstracts of these additional CWP manufacturer studies are 

provided in Appendix H. Some of these additional studies are from monitoring studies of CWP

manufacturing mills outside the U.S.

The IARC study cited exposure monitoring studies for various types of settings (including 

offices, homes, and institutional and public buildings) in various countries (including countries in 

North America, Europe, South America, Asia, and Australia). Monitoring data for U.S. office 

buildings from the IARC study were not used because they were not recent data (they were dated 

prior to 1990). The RIOPA data were not used as the RIOPA project focused on individuals’ 

exposures through-out their day. Although limited information was collected to estimate an 

individual’s exposures during their occupations, occupational exposures were not the focus of 

the project. The DEARS also focused on personal, residential, and outdoor monitoring. 

Occupational exposures were not the focus of DEARS. In contrast, OSHA IMIS and EPA’s 

BASE study are both focused on occupational exposures. Recent data on formaldehyde 

concentrations in Hong Kong office buildings were reported in Wong et al. (Wong 2006a). The 

minimum of the range of these concentrations is similar to the lowest value reported in the BASE 
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study (BASE 1998a), while the maximum of the range is over twenty times greater than the 

maximum reported in the BASE study. However, these Hong Kong data were not used because 

they may not be relevant to exposure in U.S. office buildings. Specifically, it is unknown how 

determinants of formaldehyde inhalation exposure in Hong Kong office buildings compare to 

those in U.S. office buildings, such as sources of airborne formaldehyde including the amount of 

CWP present in office buildings and their formaldehyde emission rates and ventilation rates. As 

compared to the above mentioned studies, the BASE study results are the most relevant to this 

assessment of formaldehyde inhalation exposure in office buildings and are adequate and 

sufficient for the purpose of providing perspective on the results of this exposure assessment. 

Therefore, the BASE study results are presented in this assessment while information from the 

other studies is not included.

Dermal exposure was not included in data searches. Instead, this assessment has relied solely 

upon mathematical modeling for dermal exposure assessments.

Appendix B of this report presents the quality criteria used during the literature search and data 

compilation. These quality criteria represent the preference for selecting data. The collected 

data used in this assessment meet these quality criteria.

3.2 Compilation of Pre-Baseline Exposure Monitoring Data

Baseline formaldehyde occupational exposure monitoring data are not available because the 

baseline occurs in the future in the year 2013. As described in Section 3.1, a literature search for 

pre-baseline exposure monitoring data was conducted as part of the data gathering for this 

assessment. Pre-baseline exposure monitoring data from OSHA IMIS and the EPA BASE study

were compiled and evaluated for adequacy for use in the assessment of baseline exposure and the 

effect of analytical options on baseline exposure.

The compiled inhalation exposure monitoring data, which are described below, were not used in 

the assessment of exposure at the baseline or for the analytical options. The reasons that these 

data were not used to assess exposure are discussed below. However, these data are still 

considered useful for reasons also discussed below.

Manufacturing, Composite Wood Product Fabrication, Wholesale and Retail

Pre-baseline formaldehyde exposure monitoring data for manufacturing, fabrication, wholesale 

and retail facilities were obtained from the OSHA IMIS database (OSHA 2009a). At the time 

the OSHA IMIS data were obtained (June 2010), the most current data were from 2009. Of the 

collected IMIS data, only data from the period of 2002 to 2009 were considered for use in the 

assessment because some information on the production-weighted average emission levels and 

the range of emission levels of domestically-produced CWP during the pre-baseline period of 

2002 to 2009 is available. This information is presented in Table 3-1; as seen in this table, the 

production-weighted average emission levels for CWP domestically-produced during the period 

of 2002 to 2009 were close to the CARB Phase 1 limits, especially after 2008.

The pre-baseline OSHA IMIS inhalation exposure monitoring data were determined to not be 

adequate for the assessment of baseline exposure concentrations and the effect of the analytical

options on baseline exposure concentrations due to the following three reasons:
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1. The extent to which exposure levels reported in OSHA IMIS will be affected by the 

limits on CWP formaldehyde emission rates set by FSCWPA is uncertain;

2. The OSHA IMIS data may not be representative of exposure levels that are associated 

with formaldehyde off-gassing emissions from the three CWPs with emission rates equal 

to baseline or analytical option emission rates; and

3. It is unknown whether the OSHA IMIS exposure monitoring data are representative of 

the exposure of the entire population of exposed workers during the pre-baseline period 

of time associated with these data.

The above three reasons are further discussed below.

First, the extent to which the sources of exposure associated with the compiled OSHA IMIS 

monitoring data will be affected by the FSCWPA is uncertain. OSHA’s occupational exposure 

limits apply to aggregate exposure and not to exposure due to any specific source. Accordingly, 

the OSHA IMIS, which is described in Appendix F, does not contain information on the sources 

of formaldehyde that contributed to the observed exposure concentrations, which are a measure 

of aggregate exposure where more than one source of exposure existed. As discussed in Section 

4, sources other than the off-gassing of formaldehyde from the three CWPs may contribute to 

formaldehyde occupational exposure during the life cycle of CWPs. Therefore, the compiled 

OSHA IMIS monitoring data may be associated with sources of exposure other than off-gassing 

from the three CWPs. The contributions of any such sources to the observed inhalation exposure 

concentrations are not expected to be affected by the limits on CWP formaldehyde emission rates 

set by the FSCWPA. Hence, EPA is not able to use the OSHA IMIS data to accurately assess 

the effect of analytical options on baseline exposure because the extent to which the exposure 

levels reported in OSHA IMIS will be affected by the CWP emission rate limits set by FSCWPA 

is uncertain.

Second, the pre-baseline OSHA IMIS data may not represent baseline or analytical option 

exposure levels. Levels of formaldehyde in U.S. workplaces across multiple industries have 

decreased from 1979 to 2001 according to a 2008 study of IMIS data (Lavoue 2008a). This 

decrease in formaldehyde levels could be due to OSHA’s implementation of a formaldehyde 

PEL of 1 ppm in 1987 and implementation of the current PEL of 0.75 ppm3in 1992 (Lavoue 

2008a). Manufacturers reduced formaldehyde emissions from composite wood products by 80 

to 90 percent from the levels of the early 1980s (CPSC 1997a). A decline in emission levels also 

occurred during the last decade as illustrated in Table 3-1. As discussed above, this table 

contains emission level data for domestically-manufactured CWPs during the pre-baseline period 

of 2002 to 2009. The emission level data in Table 3-1 indicate that domestic manufacturers 

produced national production-weighted average emission levels close to the CARB ATCM 

Phase 1 limits in 2002; however, the manufacturers also produced CWPs with a wide range of 

emission levels. Furthermore, the emission levels of domestically-manufactured CWPs were 

 

3

For formaldehyde, OSHA has established a PEL of 0.75 ppm as an 8-hour time-weighted average exposure and 2 

ppm as short-term exposure limit (maximum allowed exposure for 15 minutes) for all workplaces (OSHA 2008b). 

The action level is set at 0.5 ppm and requires, among other things, implementation of supervision and follow-up 

procedures when worker exposure exceeds this value. OSHA considers formaldehyde a potential human carcinogen 

(OSHA 2008b).
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trending towards a greater adoption of the CARB ATCM Phase 1 limit between 2002 to 2009, 

but a high percentage of CARB ATCM Phase 1 adoption was not expected until 2009.

Therefore, to the extent that the compiled OSHA IMIS pre-baseline inhalation exposure 

monitoring data are associated with off-gassing of formaldehyde from the three CWPs of 

interest, these data are associated with pre-baseline emission rates for these CWPs. Therefore, 

the OSHA IMIS exposure levels may not be representative of exposure levels resulting from offgassing of formaldehyde from CWPs with baseline or analytical option emission rates.

Third, it is uncertain whether the OSHA IMIS data are representative of the exposure 

concentrations for the entire population of exposed workers during the pre-baseline period of 

time in which exposure monitoring to obtain these data occurred. For some life cycle stages, 

very few monitoring data were compiled. However, even if an adequate amount of data were 

available, it is uncertain whether the inspected facilities in which the exposure concentrations 

were observed were selected randomly. Therefore, it is unknown whether such exposure 

monitoring data are representative of the exposure of the entire population of exposed workers 

during the pre-baseline period of time associated with these data.

Due to the three considerations discussed above, the OSHA IMIS monitoring data were not used 

to assess baseline exposure concentrations and exposure concentrations for the analytical

options. Due to lack of adequate exposure monitoring data, baseline exposure and the effect of 

analytical options on baseline exposure are assessed using mathematical modeling as described 

in Section 3.3. However, the monitoring data are still useful. The monitoring data can provide a 

perspective as to observed formaldehyde exposures in industries. Additionally, monitoring data 

obtained from OSHA IMIS provide exposure measurements by worker activity and thereby 

provide perspective as to the different worker activities in each industry that can result in 

formaldehyde exposure.

Table 3-1. Pre-Baseline Formaldehyde Emission Levels for Domestically-Produced 

Composite Wood Products

Timeline

Information 

Source HWPW a PB b MDF b

2002 CARB survey

Production-Weighted Average

0.09 ppm 0.18 ppm 0.25 ppm

% of Production Represented in Survey

73% 53% 83%

Range in Survey Responses

0.07 to 0.75 ppm 0.13 to 0.24 

ppm

0.03 to 0.31 

ppm

End of 2008 / 

Beginning of 

2009

ANPR 

Submissions

75% of domestically-produced CWP

were CARB Phase 1 compliant

96% of 

domesticallyproduced CWP 

were CARB 

P1 compliant

96% of 

domesticallyproduced CWP

were CARB 

P1 compliant

Later in 2009 ANPR 

Submissions

90% of domestics expected to be 

CARB P1 compliant -- --

a – A submission from HPVA in May 2008 estimated that domestically-produced HWPW will be in compliance 

with CARB Phase 1. Phase 2 limits require new technologies, which have not been in commercial use and some 

only recently invented and patented. Additionally, a submission from HPVA in February 2009 estimated that 75% 
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Page 16

of North American HWPW was CARB certified and soon 90% or more will be CARB certified. “CARB 

certified” is assumed to mean CARB Phase 1 per the statements made in the May 2008 submission. The term

“soon” is uncertain; therefore, the point in time in which 90% of domestics were expected to meet CARB Phase 1 

is uncertain.

b – A submission from CPA in May 2008 stated that “almost all” domestic production is expected to be compliant 

with CARB Phase 1 and 2. The volume related to “almost all” is uncertain. This submission also states that 

“eventually” this rate of compliance would be reached; the time frame associated with “eventually” is uncertain. 

CPA did estimate that 96% of domestics were Phase 1 compliant by the end of 2008.

Commercial Use (Office Buildings)

For office buildings, formaldehyde inhalation exposure monitoring data were obtained from the 

EPA Building Assessment Survey Evaluation (BASE) study. The BASE study was a five-year 

study to characterize determinants of indoor air quality (IAQ). The BASE study collected indoor 

air quality data from 100 randomly selected public and commercial office buildings in 37 cities 

in 25 states from 1994 to 1998. The buildings were all occupied buildings randomly selected 

from cities with populations greater than 100,000 within ten climatic regions. The studied 

buildings were primarily (73%) located in urban surroundings. Ninety-eight percent of the 

buildings had mechanical ventilation and 44 percent had operable windows. Within each 

building, a test space with a target population greater than 50 occupants, residing on no more 

than three floors, and served by no more than two air-handling units was randomly selected. 

Buildings with highly publicized indoor environmental quality problems were excluded. The 

data compiled through the BASE study include general information regarding the building itself, 

area monitoring of indoor pollutant concentrations, basic occupant statistics, occupant health 

symptoms and perceptions of indoor air quality, and information about the design, maintenance 

and operation of building heating, ventilating, and air conditioning (HVAC) systems. A 

summary of the results of the BASE study is given in Section 4.5.3.

The BASE study does not contain any information on the sources of the monitored formaldehyde 

indoor air concentrations. Even while assuming that CWPs were the main source of monitored 

formaldehyde, the BASE study inhalation exposure monitoring data are not adequate for 

assessing exposure concentration in this assessment because the emission levels of such CWPs in 

the studied buildings are unknown. As indicated in Table 3-1 and discussed in the subsection 

above, the formaldehyde emission levels of new CWPs have been decreasing with time and, 

therefore, the emission levels of new CWPs depend on their date of manufacture. Furthermore, 

formaldehyde emission levels of CWPs decay with time and, therefore, the emission level of 

aged CWPs depend on the emission level when manufactured and the duration of time they have 

been in use. Although the BASE study was conducted in 1994 to 1998, the vintage of the office 

furniture (i.e., the year in which the office furniture were built), which may contain CWPs and 

are a likely source of formaldehyde emissions as further discussed in this document, is unknown

for each studied building. Therefore, the emission levels of any CWPs that are components of 

office furniture in the monitored office buildings at the time the monitoring occurred are 

unknown.
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3.3 Exposure Assessment Methods and Assumptions

This section describes the methods used for assessing baseline exposures, which are due solely to 

off-gassing from CWPs and ventilation with ambient air, the effect of the analytical options on 

these baseline exposures, and the assumptions underlying the assessment methods.

Baseline indoor air concentration and the effect of the analytical options on baseline indoor air 

concentration were assessed for CWP fabrication and office buildings; the methods for these 

assessments are discussed below. Baseline indoor air concentration and the effects of the 

analytical options on baseline indoor air concentration were not assessed quantitatively for the 

CWP manufacturing, wholesale and retail life cycle stages due to data gaps, and only qualitative 

assessments were made.

The goal of this assessment was to assess aggregate formaldehyde indoor air concentration in 

each assessed life cycle stage. Aggregate indoor air concentration is the sum of the 

concentration contributed by off-gassing of the three CWPs, the concentration contributed by

other formaldehyde sources in the workplace, and the concentration of formaldehyde in ambient 

outdoor air. However, due to data gaps, this assessment only assesses formaldehyde indoor air 

concentration that is due to off-gassing of the three CWPs and the concentration of formaldehyde 

in ambient outdoor air.

For CWP fabrication sites, as discussed in Section 4.2.1, there is indication that sources of 

formaldehyde other than the off-gassing of formaldehyde from CWPs may exist. However, the 

extent to which other sources of formaldehyde contribute to worker exposure in CWP fabrication 

sites is unknown. Attempts to develop methods to estimate concentration contributions from 

other sources during CWP fabrication were not successful due to data gaps.

On the other hand, in homes the most significant sources of formaldehyde are likely to be CWPs 

made from UF resins (USEPA 2011b). The literature search did not identify information to 

indicate that sources of formaldehyde in office buildings are significantly different than in 

homes. Therefore, it is assumed that CWPs are the most significant source of formaldehyde in 

office buildings. It is noted in this regard that the concentration of airborne formaldehyde tends 

to be lower in office buildings as compared to residential structures. EPA compiled residential 

indoor air formaldehyde monitoring data (USEPA 2009b). A comparison of these data with the 

monitoring data of the BASE study (BASE 1998a) shows that the central value of the indoor air 

concentrations in office buildings are for the most part lower than the central values of 

residences. This observation is also indicated by a Health Effects Institute report (HEI 2007a). 

However, this comparison neither supports nor detracts from the assumption made here about the 

predominant type of emission source in office buildings because airborne concentration is a 

function of not only the type of emission source, but also its quantity as well as the ventilation 

rate. These last two factors are not expected to be similar for office buildings and residential 

structures.

Dermal exposures to formaldehyde in liquid mixtures were quantitatively assessed for 

manufacturing. Dermal exposures were assessed only qualitatively for the CWP fabrication, 

wholesale, retail, and commercial use life cycle stages. Due to data gaps, quantitative dermal 

exposure estimates for manufacturing were only made for pre-baseline conditions; baseline and 
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analytical option dermal exposures could not be estimated. The qualitative dermal exposure 

assessments for CWP fabrication, wholesale, retail, and commercial use were made for baseline 

and analytical options.

The use of respirators as personal protective equipment (PPE) for CWP manufacture and 

fabrication was considered based on the review of OSHA inspection reports. However, a limited

number of inspection reports were available for review and a conclusion as to the prevalence of 

the use of respiratory protection in these life cycle stages could not be determined. OSHA 

guidance on safe practices in the woodworking industry was also considered and is summarized 

in this assessment report.

Exposure duration (the hours of exposure per day) and frequency (the days of exposure per year)

for all assessed life cycle stages with the exception of office buildings were assessed based on 

census data on pre-baseline aggregate production hours.

The number of exposed workers in each life cycle stage with the exception of office buildings 

was estimated to be equal to the pre-baseline number of production workers according to census 

data.

Inhalation exposure results for baseline and each analytical option are presented as average daily

concentration (ADC) and lifetime average daily concentration (LADC). The equations for ADC 

and LADC are presented in Appendix E. ADC and LADC are used as measures of exposure 

when considering non-cancer and cancer risks, respectively (USEPA 2009a). Formaldehyde 

may result in both non-cancer and cancer health effects (ATSDR 1999a; ATSDR 2010a).

The assessment results are presented in Section 4.

3.3.1 Estimation of Indoor Air Concentrations Related to Baseline and Analytical Options 

for CWP Fabrication and Office Buildings

This section discusses the mathematical models used for estimating baseline indoor air 

formaldehyde concentrations due to off-gassing of CWP in CWP fabrication sites and office 

buildings, and the effect on baseline indoor air concentrations of the FSCWPA analytical

options. As discussed in Section 3.2, the OSHA IMIS and BASE data are likely not 

representative of exposure concentrations at baseline or for the analytical options. Therefore,

mathematical modeling was used to estimate indoor air concentration for the baseline and the 

analytical options.

The mathematical models for the estimation of formaldehyde indoor air concentration in CWP 

fabrication sites and office buildings are presented in this section, while a detailed description of 

these models and their underlying assumptions is included in Appendix E. These models are 

based on the principle of mass conservation. As further discussed below, the generation rate of 

formaldehyde in these models is expressed as the product of a formaldehyde off-gassing 

emission rate and an amount of emitting surface area. This generation rate is used in 

combination with the rate of ventilation of the work space area containing the CWP emitting 

surface area. This section also contains a discussion of the determination of the values of these 

and the other model parameters of these models and the use of the models for estimating what-if 

values of indoor air concentration at CWP fabrication sites and office buildings. Mathematical 
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modeling was not applied to other life cycle stages because data were not available to estimate 

the model parameters for the other life cycle stages.

3.3.1.1 Method for Estimation of Indoor Air Concentration for CWP 

Fabrication

At steady-state, a mass balance equates the formaldehyde generation rate due to off-gassing from 

HWPW, PB, and MDF present at a CWP fabrication site to the rate at which airborne 

formaldehyde is exhausted from the CWP fabrication site through ventilation with outdoor air. 

As further discussed in detail in Appendix E, the mathematical model for indoor air 

concentration, which is derived from the mass balance, is as follows:

 =

×



+ 

 Eqn (1)

where:

C = Average airborne formaldehyde concentration in a CWP 

fabrication site (μg/m3);

F = Emission rate (off-gassing emissive flux) of formaldehyde from 

the composite wood product (μg/m2-h);

A = Total emitting surface area of the composite wood products located 

in a CWP fabrication site (m2);

Qeffective = Effective volumetric ventilation rate for an entire CWP fabrication 

site (m3/h); and

Co

ind

= Concentration of formaldehyde in the outdoor air for industrial 

land use areas (μg/m3).

The literature search did not yield an exposure site population distribution for the input 

parameters of Equation 1, nor did it yield representative values for these input parameters for 

CWP fabrication sites. Due to these data gaps with respect to the model parameters, what-if 

values for indoor air concentration were estimated. This what-if analysis was accomplished by

estimating the range of possible values for each model parameter (with the exception of outside 

air concentration as further explained below) and calculating a range of what-if indoor air 

concentration values from the estimated ranges of the model parameters as further discussed 

below. The resulting values in the estimated range for average indoor air concentration at a 

CWP fabrication site are characterized as what-if results because each concentration value in this 

range corresponds to combinations of choices, or what-if values, for the model parameters. 

Although the prevalence of the model parameter what-if values at actual CWP fabrication sites is 

unknown, the ranges of the model parameter values should be realistic such that any given 

choice, or what-if value, for any model parameter represents a possible value at actual CWP 

fabrication sites. However, as further discussed below, the ranges of the model parameters were 

estimated with varying levels of accuracy.
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What-If Method for Calculating Indoor Air Concentration

The ranges of possible values for the model parameters were estimated as further discussed 

below. These ranges consist of low- and high-end values and average, typical, or intermediate 

values, which are presented in Table 3-4. For the purpose of this assessment, “intermediate” is 

defined as a value in-between the low-end and the high-end estimates. Low and high ends of the 

range of what-if average formaldehyde indoor air concentrations in CWP fabrication sites were 

estimated using Equation 1 from what-if values of the model parameters that are within the 

estimated ranges for these parameters and that result in a wide but realistic range of indoor air 

concentration. Due to data gaps with respect to the relative amounts of the three CWPs used at 

fabrication sites, this what-if approach for estimating indoor air concentration was applied to 

three limiting cases for the type of CWP that is present at CWP fabrication sites: only HWPW, 

only PB, or only MDF. The results of these three limiting cases are combined into ranges to 

account for mixtures of different CWP types as discussed in Section 4.2.5.

To estimate the what-if low-end indoor air concentration, three estimates of indoor air 

concentration are calculated, and the minimum value is used as the estimate for the what-if lowend indoor air concentration. The three estimates are calculated by using the low-end value for 

one parameter and the average, typical, or intermediate value for the two other varying 

parameters and repeating this twice with a different parameter having a low-end value each time. 

The estimate of the what-if high-end indoor air concentration was similarly calculated. The 

what-if estimation method is summarized in Table 3-2. An intermediate indoor air concentration 

was also calculated for each of the three limiting cases for CWP type from the typical, average, 

or intermediate values of the model parameters. Due to varying uncertainty of the 

representativeness of the estimated typical, average, or intermediate values of the model 

parameters, the extent to which these calculated intermediate indoor air concentrations are 

representative of all exposure levels is unknown.

The model results for the range of average formaldehyde indoor air concentration at CWP 

fabrication sites for the three limiting cases are presented in Section 4.2.5.
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Table 3-2. Summary of What-If Method for the Estimation of the What-If Range of 

Average Indoor Air Concentrations of Formaldehyde at CWP Fabrication Sites

Limiting Cases 

for CWP Type

Method for Calculating What-if Low- and High-End Indoor Air Concentration

Determination of What-if Values of the

Indoor Air Concentration Model 

Parameters that Result in a What-if LowEnd Indoor Air Concentration

Determination of What-if Values of the Indoor 

Air Concentration Model Parameters that Result 

in a What-if High-End Indoor Air Concentration

A total of three 

cases: HWPW 

only, PB only, or 

MDF only is used 

at a fabrication 

site

What-if low-end indoor air concentration is 

estimated as the minimum value from 

amongst three low-end estimates of indoorair concentration that are calculated from 

the following three combinations of 

parameters:

1. High-end ventilation rate, 

intermediate emitting surface 

area, weighted-average emission 

rate, and average value for the 

ambient air concentration of 

formaldehyde;

2. Low-end emitting surface area, 

typical ventilation rate, weightedaverage emission rate, and 

average value for the ambient air 

concentration of formaldehyde;

3. Low-end emission rate, typical

ventilation rate, intermediate 

emitting surface area, and average 

value for the ambient air 

concentration of formaldehyde.

What-if high-end indoor air concentration is 

estimated as the maximum value from amongst 

three high-end estimates of indoor-air 

concentration that are calculated from the 

following three combinations of parameters:

1. Low-end ventilation rate, intermediate 

emitting surface area, weightedaverage emission rate, and average 

value for the ambient air concentration 

of formaldehyde;

2. High-end emitting surface area, typical

ventilation rate, weighted-average

emission rate, and average value for 

the ambient air concentration of 

formaldehyde;

3. High-end emission rate, typical

ventilation rate, intermediate emitting 

surface area, and average value for the 

ambient air concentration of 

formaldehyde.

The basis for the ranges of values of the indoor air concentration model parameters is discussed 

below and summarized in Table 3-5.

Range of Values for Effective Ventilation Rate

Industrial ventilation rates for all industries, including those unrelated to CWP, vary from 500 to 

over 10,000 cubic feet per minute (cfm) with a typical value of 3,000 cfm (USEPA 1991a). The 

adopted range for this analysis is 500 cfm to 10,000 cfm. A mixing factor is applied to account 

for non-ideal mixing of air; the mixing factor is multiplied by the ventilation rate to estimate an 

effective ventilation rate. The value of the mixing factor ranges from 0.1 (worst-case) to 1 (ideal 

mixing) with a typical value of 0.5. The various combinations of ventilation rate and mixing 

factor are given in Table 3-3 and the resulting range of effective ventilation rate is 50 to 10,000 

cfm. The final values of effective ventilation rate selected for use in the mass balance equation 

are the following three values from Table 3-3: 50 cfm (low-end value), 1,500 cfm (typical value), 

and 10,000 cfm (high-end value).
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Table 3-3. Matrix of Ventilation Rates and Mixing Factors

Ventilation Rates 

(cfm)

Effective Ventilation Rates for each Mixing Factor (cfm)

Worst-Case Mixing Factor Typical Mixing Factor Ideal (no mixing factor)

0.1 0.5 1

10,000 (high end) 1,000 5,000 10,000

3,000 (typical) 300 1,500 3,000

500 (worst case) 50 250 500

Source: USEPA 1991a

cfm = cubic feet per minute

Range of Values for Emitting Surface Area

The emitting surface area of composite wood products in CWP fabrication sites is the most 

uncertain of the three parameters of the mathematical model. In CWP fabrication sites, CWP 

panels can be stacked, in which case the emitting surface area of the stack would be the top 

surface of the top panel plus the summation of the surface area of the edges of each panel in the 

stack. It is uncertain how many hours per day any given panel is expected to remain within a 

stack and how a stack of panels may grow or shrink throughout the day. Additionally, panels are 

handled by workers as they process the panels, which can include sawing, sanding, routing, and 

assembling (OSHA 2009a; see Appendix F for a categorization of the worker activities identified 

in the obtained OSHA IMIS data). During processing activities, all sides of the panel can be 

exposed to the air as workers handle, transfer, and process the panels. Therefore, the emitting 

surface area of a panel can be equal to all surfaces and edges of the panel for some part of a 

single day of operation. Finally, when the panels are assembled into a finished fabricated 

product, some panel surfaces can be covered due to stacking or overlapping the panels with other 

materials. There is uncertainty as to the emitting surface area of panels incorporated into a final 

fabricated product. Additionally, panels can be covered with decorative finishes or overlays. 

However, the effect of barriers due to decorative finishes or overlays is to reduce the emission 

rate of the panel but not the emitting surface area (CPA 2003a). The principle is that a finished 

or overlayed surface is still available for emission, but the actual emission rate is reduced due to 

the overlay.

Due to data gaps in information on the range of possible values for emitting surface area and due 

to the expected high variation in the value for this model parameter based on the above 

discussion, a range for this model parameter is estimated as follows. The estimate of the 

emitting surface area is based on the aggregate average throughput of CWP panels per site. 

Throughput is estimated from the estimated domestic consumption of CWP at baseline, the total 

number of CWP fabrication sites at baseline, and an estimate of the sites’ operating days per 

year. The baseline U.S. consumed volume of CWP for the three CWP types combined, which 

accounts for domestic production less exports and plus imports, is 18,045,282 m

3

(USEPA 

2010a) with a total surface area of 1,895 million m2(assuming each CWP has a thickness of 3⁄4 

inch4and that both sides of the panel are exposed to air). This quantity of material was divided 

 

4 The 2007 North American Downstream Market Report (CPA 2008a), published by the Composite Panel 

Association, provides PB and MDF panel volumes in terms of square footage at a 3⁄4 inch thickness basis. Therefore, 

a 3⁄4 inch thickness basis was assumed for these surface area calculations. The 3⁄4 inch thickness basis was assumed 

for HWPW as well, as HWPW thickness basis data were not identified.
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by the total number of assessed CWP fabrication sites, 33,737 sites (USEPA 2010a), and the 

number of operating days (which was not determined but was assumed to be equal to the 

assessed frequency of exposure of 250 days per year) to obtain 224.6 m

2

per site per day, which 

is an estimate of the daily throughput, or amount processed daily, of all three CWP types 

combined (the number of sites and the frequency of exposure are given in Section 4.2.2).

This intermediate estimate of emitting surface area is predicated on the aggregate average sitespecific throughput of CWP panels (assuming a 3⁄4 inch thickness) and that both sides of the 

panel throughput are available for emission. As discussed above, it is recognized that panels 

processed in a single day can have less than their full two sides available for emission for part of 

the day. It is additionally recognized that inventoried panels that are not processed in a given 

day can also contribute to formaldehyde emissions (such as from a stack of panels). The effect 

of these uncertainties on the intermediate estimate cannot be quantified. Since the estimation 

method of emitting surface area is highly uncertain, a range of values for emitting surface area 

was adopted by assuming that the low-end and high-end values are equal to 10% and 1,000%, 

respectively, of the intermediate estimate of emitting surface area based on throughput. The 10% 

and 1,000% values of this intermediate estimate are hereinafter referred to as the low-end and 

high-end estimates, respectively. The adopted range for emitting surface area including the 

intermediate value is given in Table 3-4.

Range of Values for Emission Rate

The emission rate is the only parameter of the mass balance equation that will be affected by the 

FSCWPA; therefore, values for this parameter were obtained for the baseline and for each of the 

analytical options. Emission levels for the baseline and for the analytical options were obtained 

from the EPA market profile (USEPA 2010a) and the EPA draft exposure assessment (USEPA 

2009b), respectively, and are presented in Appendix D. Uncertainty in the values of these 

emission levels and their applicability to the estimation of average indoor air concentration in a 

CWP fabrication site is discussed below.

Representativeness of Emission Levels Reported in the EPA Market Profile

The emission level estimates for domestic and Canadian CWPs at baseline were obtained from 

an EPA survey of domestic CWP manufacturers. The survey received the following response 

rates from the manufacturing facilities (mills) that received the survey: 85% of the 39 HWPW 

mills surveyed; 100% of the 20 MDF mills surveyed; and 97% of the 31 PB mills surveyed. The 

mills surveyed only included mills subject to FSCWPA and did not include mills that only

produce products exempted or not otherwise covered by FSCWPA. Therefore, the survey results 

for domestic CWPs are likely representative of all U.S. CWP manufacturing mills subject to 

FSCWPA. However, the EPA market profile notes that some survey responders only provided 

information about the compliance standards being achieved but not specific emission levels 

(USEPA 2010a). Therefore, the surveyed population of mills is likely representative of U.S. 

mills subject to FSCWPA. The emission level estimates for non-Canadian imported CWPs at 

baseline were estimated from data from a 2009 presentation by Professional Service Industries 

(PSI), a CARB third-party certifier (TPC) that mainly certifies mills located in Asia. The mills 

certified by PSI are major sources of CWPs imported into the U.S. (USEPA 2010a). The EPA 

market profile discusses the method in which data were obtained from the presentation and used 
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to estimate imported CWP emission levels at baseline (USEPA 2010a). The representativeness 

of the emission level values for non-Canadian imported CWP is uncertain.

Accuracy of Emission Level Values Reported in the EPA Market Profile

As discussed above, some survey responders only stated the compliance standard they would 

achieve and not the specific emission levels of their products; in such case, the actual emission 

level may be lower than the compliance standard. All survey data were assumed to represent 

actual emission levels of products, and therefore these data may be an overestimate of emission 

level. CARB ATCM emission standards are based on the ASTM E1333 chamber test method 

(ASTM 2002a). Therefore, it is assumed that emission levels reported in the survey and 

provided from PSI are based on the ASTM E1333 chamber test method (see Appendix E for a 

description of ASTM E1333). The emission levels from the survey and the PSI presentation are 

converted to emission rates in units of flux for use in the indoor air concentration mathematical 

model according to the equations described in ASTM E1333 (see Appendix E). Another 

consideration with respect to the accuracy of the emission levels reported in the EPA market 

profile is the accuracy associated with the measurements made to obtain these values. ASTM 

E1333 discusses the precision and bias of the large chamber test method in general. However, 

ASTM E1333 does not discuss the accuracy and precision of the analytical test method 

recommended in ASTM E1333 for measuring formaldehyde levels in the chamber air samples: 

NIOSH 3500 chromotropic acid test procedure. The accuracy and precision of this procedure is 

discussed in NIOSH 3500 (NIOSH 1994a). ASTM E1333 does not discuss the overall accuracy

of the test chamber method for determining accurate formaldehyde off-gassing emission rates. 

Additionally, it is uncertain if chamber test results from ASTM E1333 accurately represent 

actual off-gassing rates in real world industrial settings, including CWP fabrication mills. For 

ASTM E1333 chamber test results to accurately represent off-gassing rates in actual CWP 

fabrication mills, the ASTM E1333 parameters should be consistent with the actual conditions in 

the fabrication sites. However, adequate data to perform this comparison were not available. 

This assessment did not consider how ASTM E1333 uncertainties would impact the overall 

uncertainty of the assessment results. However, it is likely that ASTM E1333 uncertainties are 

of small impact to the assessment results compared to the uncertainties of other mathematical 

model parameters. It is also uncertain as to what extent manufacturers will actually obtain their 

predicted emission levels in 2013.

Applicability of Emission Level Values Reported in the EPA Market Profile to the Estimation of 

Average Indoor Air Concentration in a CWP Fabrication Site

An additional consideration is the decay with time of CWP formaldehyde emission levels. 

Various literature sources have discussed the decay of formaldehyde emission levels with time, 

such as Groah 2005a, Zinn 1990a, and Gammage 1988a. A wide range of values for the 

formaldehyde emission level half life for PB, MDF, and HWPW were reported in these articles. 

The studies, which span a period of approximately 20 years, cite CWP emission level half lives 

ranging from less than three months to less than two years. Not all tests used the same test 

method for determining emission level half life. Additionally, the test method conditions may

not be similar to the conditions of storage and transport between CWP manufacture and 

fabrication. Therefore, the test results may not be applicable for the emission level decay

experienced during storage and transport. The initial emission level has a moderately strong 
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influence on half life (Groah 2005a). A higher initial emission level will result in a more rapid 

decay (Groah 2005a). Therefore, half lives from older studies may not be applicable for newer 

or future CWPs with lower initial emission levels, which would have less rapid decays.

The available literature on formaldehyde emission level decay indicate that CWPs at CWP 

fabrication sites could have emission levels less than their emission levels at the time of their 

manufacture if the time for distribution from manufacturer to fabricator is considerable and 

depending on the conditions of storage and transport prior to delivery to the fabricator. 

However, the residence time of CWPs at CWP fabrication sites is small and would likely not 

result in significant further emission level decay while the CWPs are at the fabrication site. 

Formaldehyde emission level decay is not accounted for in this assessment due to data gaps in 

decay rates for CWPs manufactured at the baseline or under any of the analytical options. In this 

assessment, formaldehyde concentration modeling at CWP fabrication sites assumes the 

emission levels from the EPA market profile (USEPA 2010a) are for newly-manufactured 

CWPs, which may overestimate the actual emission levels at CWP fabrication sites.

The range of emission levels and corresponding emission rates, including weighted-average 

values for the baseline and analytical options, is given in Table 3-4. These values account for 

both domestically manufactured and imported CWPs. See Appendix D for a complete list of the 

emission levels for baseline and each analytical option. It is important to note that CWPs will 

continue to emit formaldehyde as they are overlayed and after they are overlayed. However, 

emissions from overlayed panels at CWP fabrication sites were not accounted for in the 

estimation of indoor air concentration. Many overlay materials serve as a barrier and reduce 

formaldehyde emissions from 50% to as much as 95% or higher (CPA 2003a). Therefore, 

emissions from overlayed products have a diminished effect on indoor air concentrations 

compared to non-overlayed products at CWP fabrication sites.

Value for Ambient Air Formaldehyde Concentration

Limited statistics of ambient air formaldehyde concentrations are available in the EPA draft 

report Formaldehyde from Pressed Wood Products: Exposure Assessment (USEPA 2009b). 

Table 3-1 of the draft exposure assessment provides ambient air formaldehyde concentrations for 

various land use categories. The CWP fabrication indoor air concentration mathematical model 

uses the average value of the ambient formaldehyde concentration for industrial land use areas. 

The average value is chosen for use in this mathematical model since the low standard deviation 

indicates limited variation in this parameter and the average value is representative. This 

average value of 6.28 μg/m3is kept constant throughout the what-if calculations.
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Table 3-4. Estimated Values for Parameters in the Mathematical Model for Average 

Indoor Air Concentration at a CWP Fabrication Site for the Baseline and the Analytical

Options

Parameter Name

Scenario

(Analytical

Option)

Value of Parameter

Units

Intermediate / 

Typical / Average

Value

Low-End

Value

High-End

Value

Emitting Surface 

area

All m

2

224.6 22.5 2,246

Ventilation Rate All cfm

(m3/h)

1,500

(2,549)

50

(85)

10,000

(16,990)

HWPW Emission 

Level

Baseline

ppm

0.04 0.013 0.163

CARB Phase 1 0.025 0.013 0.058

FSCWPA / 

CARB Phase 2 0.021 0.013 0.032

NAF 0.013 0.013 0.013

PB Emission Level

Baseline

ppm

0.06 0.013 0.384

CARB Phase 1 0.05 0.013 0.090

FSCWPA / 

CARB Phase 2 0.053 0.013 0.057

NAF 0.013 0.013 0.013

MDF Emission 

Level

Baseline

ppm

0.08 0.024 0.502

CARB Phase 1 0.07 0.024 0.140

FSCWPA / 

CARB Phase 2 0.073 0.024 0.082

NAF 0.035 0.024 0.035

Ambient (outdoor) 

Air Concentration 

of Formaldehyde

All μg/m36.28

Parameter Name

Scenario

(Analytical

Option)

Value of Parameter

Units

Intermediate / 

Typical / Average

Value

Low-End 

Value

High-End 

Value

HWPW Emission 

Rate

Baseline

μg/m2-h

60.9 18.6 232.9

CARB Phase 1 36.0 18.6 82.9

CARB Phase 2 29.8 18.6 45.7

NAF 18.6 18.6 18.6

PB Emission Rate

Baseline

μg/m2-h

81.7 18.6 548.8

CARB Phase 1 77.1 18.6 128.6

CARB Phase 2 75.8 18.6 81.5

NAF 18.6 18.6 18.6

MDF Emission Rate

Baseline

μg/m2-h

180.5 56.7 1186.5

CARB Phase 1 173.6 56.7 330.9

CARB Phase 2 172.5 56.7 193.8

NAF 81.6 56.7 82.7

Notes: Table 3-5 indicates the sources of these data. Emission rates are shown as both emission levels in units of

ppm and as emission rates in units of flux in μg/m2-h for convenience of the reader. Emission levels are assumed 

to represent the measured concentration from ASTM E1333, while emission rates in units of flux represent the 

emission rate value calculated from the measured concentration and the ASTM E1333 test parameters. Appendix 

E describes ASTM E1333 and the conversion between emission levels in units of concentration and emission rates 

in units of flux.
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Table 3-5. Data Sources for the Estimation of Parameters of the Mathematical Model for 

Average Indoor Air Concentration at a CWP Fabrication Site

Parameter Name

Intermediate

Value Low-End Value High-End Value

Emitting Surface Area

(see “Range of Values for Emitting 

Surface Area” in Section 3.3.1.1)

Aggregate average 

daily throughput 

estimated as the 

baseline U.S.

consumed volume 

of CWP divided by 

the assessed 

number of 

fabrication sites and 

the assessed 

exposure frequency

10% of aggregate 

average daily 

throughput

1,000% of aggregate 

average daily 

throughput

Effective Ventilation Rate

(see “Range of Values for Effective 

Ventilation Rate” and Table 3-3 in

Section 3.3.1.1)

Typical ventilation 

rate multiplied by 

typical mixing 

factor.

Worst-case

ventilation rate 

multiplied by worstcase mixing factor

High-end ventilation 

rate assuming ideal 

mixing (no mixing 

factor applied)

HWPW, PB, or 

MDF Emission 

Rates

Baseline 

Values

Productionweighted average

calculated from 

data in Table D-3 in

Appendix D

Minimum emission 

rate for data in Table 

D-3 in Appendix D

Maximum emission 

rate for data in Table 

D-3 in Appendix D

Analytical

Option 1: 

CARB Phase 1

Productionweighted average

calculated from 

data in Table D-4 in

Appendix D

Minimum emission 

rate for data in Table 

D-4 in Appendix D

Maximum emission 

rate for data in Table 

D-4 in Appendix D

Analytical

Option 2: 

FSCWPA/ 

CARB Phase 2 

Productionweighted average

calculated from 

data in Table D-5 in

Appendix D

Minimum emission 

rate for data in Table 

D-5 in Appendix D

Maximum emission 

rate for data in Table 

D-5 in Appendix D

Analytical

Option 3: NAF 

Productionweighted average

calculated from 

data in Table D-6 in

Appendix D

Minimum emission 

rate for data in Table 

D-6 in Appendix D

Maximum emission 

rate for data in Table 

D-6 in Appendix D

Ambient (outdoor) Air Concentration 

of Formaldehyde

Average value for the industrial land use category from Table 3-1 in

USEPA 2009b.

3.3.1.2 Method for Estimation of Indoor Air Concentration for Office Buildings

At steady-state, a mass balance equates the formaldehyde generation rate due to off-gassing from 

HWPW, PB, and MDF that are components of an office workstation5to the rate at which 

airborne formaldehyde is exhausted from the volume of the office building containing the 

workstation through ventilation with outdoor air. Based on the work by Carter and Zhang 

(Carter 2007a), formaldehyde indoor air concentration is estimated for two types of 

 

5 BIFMA M7.1-2007 defines a workstation, or workstation system, as a collection of office furniture (excluding 

seating) that forms a complete office work space for an individual occupant.
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workstations: open plan workstations and private office workstations. Furthermore, both 

workstation types contain the following components that may emit formaldehyde: panels, work 

surfaces, and storage external areas, but storage external areas are assumed to not have any

formaldehyde emissions.

The office building mathematical model is described in greater detail in Appendix E and is 

displayed in Equation 2.

 =

×()×××

×()× × × 



+ 

 Eqn (2)

where:

C = Average airborne formaldehyde concentration in the volume of the 

office building containing the workstation (μg/m

3

);

Apanels = Emitting surface area of panels in the office workstation (m

2

);

Awork surfaces = Emitting surface area of work surfaces in the office workstation

(m

2

);

Q = The rate of ventilation with outdoor air that affects the volume of 

the office building containing the workstation (m3/h);

ECWP = Emissive flux (emission rate) of the composite wood product used 

to construct the workstation component type (μg/m2-h) (CWP = 

HWPW, PB, or MDF);

BE = Barrier effectiveness of the finishing, or overlay, of the 

workstation component type, expressed as a unitless fraction;

Finpanels = Fraction of the panels’ surface area that is finished, or overlayed,

with a barrier effectiveness of BE, expressed as a unitless fraction;

Finwork surfaces = Fraction of the work surfaces’ surface area that is finished, or 

overlayed, with a barrier effectiveness of BE, expressed as a 

unitless fraction; and

Co

com

= Concentration of formaldehyde in the outdoor air for commercial 

land use areas (μg/m3).

Representative values for some of the model parameters of this mathematical model, including 

workstation component emitting surface area, ventilation rate, formaldehyde emission rates for 

each of HWPW, PB, and MDF, and outdoor air formaldehyde concentration, were obtained 

through a literature search. On the other hand, information was lacking on the relative amounts 

of the three CWPs used in the fabrication of office workstations, representative values for the 

extent to which the workstation components are finished or overlayed, and the barrier 

effectiveness of the finish or overlay. Due to these data gaps on representative values for these 

model parameters, what-if values for indoor air concentration were estimated. What-if values for 

indoor air concentration were estimated by first estimating the range of possible values for the 

following parameters: formaldehyde emission rates for all three CWP types; extent of finishing 

or overlay of each workstation component; and the barrier effectiveness of the finishing or 

overlay. Then, these ranges of parameter values and the representative values for the remaining 

model parameters were used in Equation 2 to estimate what-if values for indoor air 

concentration.
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What-If Method for Calculating Indoor Air Concentration

The ranges of possible values for three model parameters (CWP emission rate, extent of 

finishing or overlay, and barrier effectiveness) were estimated as further discussed below. These 

ranges consist of low- and high-end values and average or intermediate values, which are 

presented in Table 3-8, which also contains the representative values for the remaining model 

parameters. For the purpose of this assessment, “intermediate” is defined as a value in-between 

the low-end and the high-end estimates. Low and high ends of the range of what-if average 

formaldehyde indoor air concentrations in the workstation volumes were estimated using 

Equation 2 from the bounding values of the range of values for the above mentioned three model 

parameters and from the representative values of the remaining model parameters so as to obtain 

a wide range of indoor air concentration. Due to data gaps with respect to the relative amounts 

of the three CWP types used in the construction of office furniture, this approach for estimating 

what-if indoor air concentration was applied to three limiting cases for the type of CWP of which 

the office furniture is constructed: only HWPW, only PB, or only MDF. The results of the three 

limiting cases are combined into ranges to account for mixtures of different CWP types as 

discussed in Section 4.5.4. What-if values for low-end and high-end indoor air concentration

were estimated as summarized in Table 3-6. An intermediate indoor air concentration was also 

calculated for each of the three limiting cases for the CWP type from the intermediate values of 

the model parameters. The representativeness of the range of values for intermediate indoor air 

concentration (calculated from the three limiting cases for CWP type) is limited by the 

representativeness of the intermediate values for the extent of finishing and barrier effectiveness, 

which are unknown. The intermediate values for the remaining model parameters are expected 

to be representative of real world values.
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Table 3-6. Summary of What-if Method for the Estimation of the What-if Range of 

Average Indoor Air Concentrations of Formaldehyde in Workstation Volumes

Limiting Cases for 

CWP Type

Method for Calculating What-if Low- and High-End Indoor Air Concentration

What-if Values for Emission Rate, Extent 

of Finish or Overlay, and Barrier 

Effectiveness that are used to Calculate a 

What-if Low-End Indoor Air 

Concentration 1

What-if Values for Emission Rate, 

Extent of Finish or Overlay, and 

Barrier Effectiveness that are used to 

Calculate a What-if High-End Indoor 

Air Concentration 1

Workstation panels and 

work surfaces are 

constructed of:

 Only HWPW;

 Only PB; or 

 Only MDF 

 The emission rate of the (unfinished) 

CWP is equal to the low-end value in a 

range of values for the emission rates for 

the unfinished CWP.

 Both sides of workstation panels and 

workstation work surface are finished or 

overlayed, and the barrier effectiveness

of the finishing or overlay is equal to a 

highest value in a range of values for 

barrier effectiveness.

 The emission rate of the 

(unfinished) CWP is equal to the 

high-end value in a range of 

emission rates for the unfinished 

CWP. 

 Both sides of workstation panels 

and the lower side of the 

workstation work surface are 

unfinished (their barrier 

effectiveness is 0%), and the upper 

side of the workstation work surface 

is finished or overlayed and has a 

barrier effectiveness equal to the 

lowest value in a range of values for 

the barrier effectiveness.

1 The representative values for the remaining model parameters (ventilation rate, workstation component emitting 

surface area, and outdoor air formaldehyde concentration) were used in the calculation.

The values of all of the model parameters and their bases are given in Table 3-8 below.

Values for Emitting Surface Area and Ventilation Rate

The emitting surface area of each workstation component and the ventilation rate of the work

space volume containing the workstation with outdoor air were obtained from the BIFMA / 

ANSI M7.1-2007 standard test method (BIFMA 2007a), which is based on the work by Carter 

and Zhang (Carter 2007a) and their analysis of actual office building floor plans and actual office 

workstations. The BIFMA / ANSI M7.1-2007 standard test method uses representative values of 

workstation component emitting surface areas and ventilation rates for the purpose of modeling

the impact on office indoor air volatile organic compound (VOC) concentrations due to office 

furniture emissions. Therefore, the values for these parameters obtained from BIFMA M7.1-

2007 are treated as representative values for the purpose of this assessment. These values are 

kept constant and are not varied.

Range of Values for Workstation Component Emission Rate

The BIFMA standard M7.1-2007 and the work by Carter and Zhang do not contain any 

information on observed formaldehyde emission rates of actual office workstations. Carter and 

Zhang provide example workstation emission rates of formaldehyde but do not discuss the 

statistical significance of these values such as being representative, worst case, etc. Therefore, 

workstation component emission rates (emission rates for finished CWPs used to construct the 
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workstation) were estimated using information on CWP emission rates, extent of finishing, and 

barrier effectiveness. These three model parameters are discussed in this subsection.

The CWP emission rate is the only parameter of the mass balance equation that will be affected 

by the FSCWPA; therefore, values for this parameter were obtained for the baseline and for each 

of the analytical options. Emission levels for the baseline and for the analytical options were 

obtained from the EPA market profile (USEPA 2010a) and the EPA draft exposure assessment 

(USEPA 2009b), respectively, and are presented in Appendix D. The low-end and high-end 

emission rates for each CWP type are chosen from the low-end and high-end values from 

Appendix D. An average emission rate for each CWP type is calculated as a volume-weighted

average of the domestic and imported CWPs that are consumed domestically as was done in the 

CWP fabrication calculation method. Table 3-8 summarizes the emission rates used for each 

calculation step of the what-if method.

As summarized in Table 3-8, the what-if values of the extent of finishing or overlaying of panels 

used for calculating what-if low-end and high-end indoor air concentrations are zero percent and

100 percent of their emitting surface area. These values are logical bounding values, as panels 

may have both surfaces finished for aesthetic reasons or no finishing at all as a conservative 

estimate. Similarly, the what-if values of the extent of finishing or overlaying of work surfaces 

are 50 percent and 100 percent of their emitting surface area. These values are again logical 

bounding values, as work surfaces are expected to at least be finished on their upper surface for 

functional purposes. In both cases, the surface area of edges was not accounted for because its 

effect is negligible.

The what-if values for barrier effectiveness used for calculating what-if low- and high-end 

indoor air concentrations are given in Table 3-8. The low-end and high-end values for barrier 

effectiveness were the low-end and high-end values identified in the source CPA 2003a. 

Although this source listed example barrier effectiveness values, it did not describe the extent to 

which any given value represented actual office workstations. The intermediate barrier 

effectiveness was calculated using BIFMA standard M7.1-2007 and BIFMA standard X7.1-2007

(BIFMA 2007b). BIFMA standard X7.1-2007, which was also adopted as an ANSI standard, is 

a voluntary standard for meeting VOC emission limits from office furniture. This standard 

specifies a formaldehyde limit of 50 ppb as measured using the BIFMA M7.1-2007 chamber test 

for all workstation configuration types. Fabricators of office furniture who choose to fabricate 

workstations that meet the requirement of this standard must construct workstations such that 

they result in a measured chamber concentration using BIFMA M7.1-2007 that does not exceed 

50 ppb. The intermediate value for barrier effectiveness was calculated using Equation 2 subject 

to the following conditions:

 The workstation is tested according to M7.1-2007 and results in a test chamber 

formaldehyde concentration of 50 ppb according to X7.1-2007;

 The panels have 100 percent of their surfaces finished and the work surfaces have 

50 percent of their surfaces finished; and

 The workstation panel and work surface components are constructed of CWPs 

such that the CWP emission rate is equal to an average pre-baseline emission rate.
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Pre-baseline emission rates were used because these would be the prevalent emission rates at the 

time the standard was established. Therefore, the calculated intermediate barrier effectiveness is 

for the pre-baseline period and is assumed to be relevant to the baseline. Appendix E describes 

the method for calculating an intermediate barrier effectiveness in greater detail.

The emission rates used in this analysis are for new composite wood products; therefore, the 

estimated indoor air concentrations are for new office furniture. The applicability of the utilized 

emission level values to the estimation of emissions from new office furniture is uncertain 

because decay in formaldehyde emissions from newly-manufactured CWPs, which is discussed 

in Section 3.3.1.1, can occur in the intervening time between manufacture of the CWPs and their 

use as components of office furniture in an office building. Hence, the actual emission levels 

from the unfinished CWPs would be lower than the values used here resulting in an overestimate 

of the initial steady-state indoor air concentration associated with new office furniture. Emission 

level decay can continue after the initial introduction of office furniture into an office. Such 

continued decay of emissions with time and consequent decline of indoor air concentration from 

the initial steady-state level associated with new furniture was not accounted for because the 

literature search did not yield the necessary information for the estimation of this effect.

In addition to the uncertainty of the temporal decay of emission rates, the uncertainties of 

emission rates discussed for the CWP fabrication method also apply for the office buildings 

method. Some survey responders only stated the compliance standard they would achieve and 

not the specific emission levels of their products; therefore, all survey data are assumed to 

represent actual emission levels of products. CARB ATCM emission standards are based on the 

ASTM E1333 chamber test method (ASTM 2002a). Therefore, the emission levels reported in 

the EPA survey and provided from PSI described in Section 3.3.1.1 are assumed to be based on 

the ASTM E1333 chamber test method (see Appendix E for a description of ASTM E1333). 

The emission levels from the survey and the PSI presentation are converted to emission rates in 

units of flux for use in the indoor air concentration mathematical model according to the 

equations described in ASTM E1333 (see Appendix E). ASTM E1333 discusses the precision 

and bias of the large chamber test method in general. However, ASTM E1333 does not discuss 

the accuracy and precision of the analytical test method recommended in ASTM E1333 for 

measuring formaldehyde levels in the chamber air samples: NIOSH 3500 chromotropic acid test 

procedure. The accuracy and precision of this procedure is discussed in NIOSH 3500 (NIOSH 

1994a). ASTM E1333 does not discuss the overall accuracy of the test chamber method for 

determining accurate formaldehyde off-gassing emission rates.

To determine if chamber test results from ASTM E1333 accurately represent actual off-gassing 

rates in office buildings, the ASTM E1333 test parameters should be compared with typical 

office building environment properties. Using the typical values for ventilation rate and 

component emitting surface area from Table 3-8 and the typical open plan and private office 

volumes determined by Carter and Zhang (Carter 2007a) and BIFMA M7.1-2007, the CWP 

loading ratio and air change rate can be calculated and compared to those values specified in 

ASTM E1333. See Appendix E for the associated equations, a description of the ASTM E1333 

test parameters, and the typical office environment dimensions. For this comparison, only the 

workstation panels and work surfaces were used in the calculation of loading ratio, since this 

assessment assumes storage surfaces are not constructed of CWPs. Table 3-7 provides a 

comparison of the ASTM E1333 parameter values for CWP loading ratio and air change rate 
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with those in typical office environments. The ASTM E1333 parameter values for the private 

office environment result in an air change rate consistent with that in a typical private office. 

The ASTM E1333 loading ratio for MDF is similar to the total CWP loading ratio in typical 

private offices, but the loading ratios for HWPW and PB are approximately twice the value for 

typical private offices. The ASTM E1333 parameter values for air change rate and all three

loading ratios are significantly different from those specified in typical open plan environments. 

This assessment did not consider how ASTM E1333 uncertainties would impact the overall 

uncertainty of the assessment results. However, it is likely that ASTM E1333 uncertainties are 

of small impact to the assessment results compared to the uncertainties of other mathematical 

model parameters. It is also uncertain as to what extent manufacturers will actually obtain their 

predicted emission levels in 2013.

Table 3-7. Comparison of ASTM E1333 Parameter Values with Typical Office 

Environment Properties

Parameter

ASTM E1333 

Values

Typical Office Environment 

Property Values

Open Plan 

Environment

Private Office 

Environment

Air Change Rate (h-1) 0.5 ±0.05 0.92 0.53

CWP Loading Ratio (m2/m3):

HWPW 0.43

PB 0.43 1.1 0.22

MDF 0.26

Sources: ASTM 2002a; BIFMA 2007a, and Carter 2007a

This office environment model treats a workstation (either private office or open plan) as a single 

exposure zone. It also only models the mitigation of airborne concentrations due to the 

ventilation rate of outdoor air. The ventilation rate of recirculated indoor air, which can vary

from building to building, is not included in the model. The premise behind this assumption is 

that recirculated indoor air would contain the same concentration of formaldehyde as is in the 

exposure zone. This model assumes that each exposure zone is of the same type (open plan or 

private office), results in the same formaldehyde concentration, and, therefore, the exposure 

zones do not affect one another. Additionally, this model does not account for materials present 

in office buildings that may act as sinks of formaldehyde, such as carpets and wallboards

(Koontz 1996a).

Ambient (Outdoor) Air Formaldehyde Concentration

An average value for the ambient air concentration of formaldehyde is available from the EPA 

draft report Formaldehyde from Pressed Wood Products: Exposure Assessment (USEPA 2009b). 

Table 3-1 of the EPA draft exposure assessment provides ambient air formaldehyde 

concentrations for various land use categories. The average value for the commercial land use 

category, 3.26 μg/m3, is used as an estimate of the formaldehyde concentration in the outdoor air 

used in office building ventilation. This value is kept constant throughout the what-if analysis.
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Table 3-8. Estimated Values for Parameters in the Mathematical Model for Average Indoor Air Concentration Resulting from 

Emissions from Private Office and Open Plan Workstations for the Baseline and Analytical Options

Parameter Name

Workstation 

Type Scenario

Value of Parameter Used to Determine:

Units Source of Data

Intermediate

Concentration

Low-End

Concentration

High-End

Concentration

Component Emitting 

Surface Area

Private office 

workstation All scenarios

m

2

Panels: 7.63

Work surfaces: 

6.73

External storage 

surfaces: 10.55

Indoor air concentration was not 

assessed for a range of values of 

emitting surface area because 

representative values for this 

parameter were obtained from the 

BIFMA / ANSI M7.1-2007 test 

method and used for all 

calculations. Storage surfaces are 

assumed not to be constructed 

from CWPs and do not factor into 

the final equation.

BIFMA /ANSI 

M7.1-2007 test 

method

Open Plan 

workstation All scenarios

Panels: 11.08

Work surfaces: 

6.10

External storage 

surfaces: 4.57

Ventilation Rate 

Private office 

work station

All Scenarios m

3

/h

34.7 Indoor air concentration was not 

assessed for a range of values of 

ventilation rate because 

representative values for this 

parameter were obtained from the 

BIFMA / ANSI M7.1-2007 test 

method and used for all 

calculations.

BIFMA /ANSI 

M7.1-2007 test 

method

Open Plan 

workstation

15.0

HWPW Emission Rate

Applicable to 

both private 

office and 

open plan 

workstations.

Baseline

ppm

(μg/m2-h)

0.043 (60.9) 0.013 (18.6) 0.163 (232.9) USEPA 2010a

Analytical Option 

1: CARB Phase 1 0.025 (36.0) 0.013 (18.6) 0.058 (82.9)

Appendix D:

Table D-4 through 

Table D-6

Analytical Option 

2: CARB Phase 2 0.021 (29.8) 0.013 (18.6) 0.032 (45.7)

Analytical Option 

3: NAF 0.013 (18.6) 0.013 (18.6) 0.013 (18.6)

PB Emission Rate

Applicable to 

both private 

office and 

open plan 

workstations

Baseline

ppm

(μg/m2-h)

0.057 (81.7) 0.013 (18.6) 0.384 (548.8) USEPA 2010a

Analytical Option 

1: CARB Phase 1 0.054 (77.1) 0.013 (18.6) 0.09 (128.6) Appendix D:

Table D-4 through 

Table D-6

Analytical Option 

2: CARB Phase 2 0.053 (75.8) 0.013 (18.6) 0.057 (81.5)
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Table 3-8. Continued

Parameter Name

Workstation 

Type Scenario

Value of Parameter Used to Determine:

Units Source of Data

Intermediate

Concentration

Low-End

Concentration

High-End

Concentration

Analytical Option 

3: NAF 0.013 (18.6) 0.013 (18.6) 0.013 (18.6)

MDF Emission Rate

Applicable to 

both private 

office and 

open plan 

workstations

Baseline

ppm

(μg/m2-h)

0.076 (180.5) 0.024 (56.7) 0.502 (1,186.5) USEPA 2010a

Analytical Option 

1: CARB Phase 1 0.073 (173.6) 0.024 (56.7) 0.140 (330.9)

Appendix D:

Table D-4 through 

Table D-6

Analytical Option 

2: CARB Phase 2 0.073 (172.5) 0.024 (56.7) 0.082 (193.8)

Analytical Option 

3: NAF 0.035 (81.6) 0.024 (56.7) 0.035 (82.7)

Extent to Which CWP is 

Finished 

Applicable to 

both private 

office and 

open plan 

workstations

All Scenarios

Percent of 

surface 

area that is 

finished

100% of panel; 

50% of work 

surface

100% of panel; 

100% of work 

surface

0% of panel; 

50% of work 

surface

Assumed by EPA

Barrier Effectiveness of 

CWP Finish

Private office 

workstation

All Scenarios

Percent 

reduction 

in 

emission 

factor of 

unfinished 

CWP

65 a

95 b50 c CPA 2007a Open Plan 

workstation 71 a

Ambient (outdoor) Air 

Concentration of 

Formaldehyde

Applicable to 

both private 

office and 

open plan 

workstations

All Scenarios μg/m33.26

Indoor air concentration was not 

assessed for a range of values of 

ambient air concentration of 

formaldehyde because an average 

value for this parameter was 

obtained from the EPA draft 

exposure assessment and used for 

all calculations.

USEPA 2009b

a - The barrier effectiveness used to estimate the intermediate concentration was estimated by using the average pre-baseline emission rate of all CWPs (306.7

μg/m2-h) and calculating the barrier effectiveness needed to match the BIFMA/ANSI X7.1-2007 emission standard of 50 ppb assuming that 100% of panels and 

50% of work surfaces are finished. The calculated barrier effectiveness for private office and open plan workstations were 65% and 71%, respectively.
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Table 3-8. Continued

b - The highest barrier effectiveness for various barrier types provided in CPA 2003a was 95%. The highest barrier effectiveness yields the lowest 

concentration for all else being equal.

c - The lowest barrier effectiveness for various barrier types provided in CPA 2003a was 50%. The lowest barrier effectiveness yields the highest concentration 

for all else being equal.
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3.3.2 Estimation of Dermal Exposures to Formaldehyde in Liquid Resin

EPA has developed a series of standard models for quantitatively estimating worker dermal 

exposures to liquid and solid chemicals during various types of activities. To estimate dermal 

exposure, all of these dermal exposure models assume a specific surface area of the skin that is 

contacted by a material containing the chemical of interest, as well as a specific surface density

of the material on the skin. These exposures can be further normalized by accounting for the 

body weight of the worker. The specific methods used to estimate dermal exposures are

discussed in detail in Appendix E.

Dermal exposures to formaldehyde contained in liquid urea-formaldehyde (UF) resins are 

assessed quantitatively during manufacturing according to EPA’s standard default model for 

estimating dermal exposures due to two-hand dermal contact with liquids. Dermal exposures to 

formaldehyde due to pressed CWPs are not quantifiable using the EPA dermal exposure models 

for liquids and solids. Due to data gaps, quantitative dermal exposure estimates for 

manufacturing were only made for pre-baseline conditions; baseline and analytical option dermal 

exposures could not be estimated. The qualitative dermal exposure assessments for CWP 

fabrication, wholesale, retail, and commercial use were made for baseline and analytical options.

4. EXPOSURE ASSESSMENT BY LIFE CYCLE STAGE

Occupational exposures resulting from the manufacture and use of baseline CWPs and effects of

the analytical options on the baseline exposures were estimated for CWP fabrication and office 

building occupancy using the methods described in Section 3. Exposures were not assessed 

quantitatively for CWP manufacture, wholesale, and retail due to data gaps. Instead, qualitative 

assessments were made for these life cycle stages. Exposures were not assessed for on-site 

construction using CWPs and for recycling and disposal of CWPs due to data gaps as discussed 

in Section 2.

4.1 Exposure Assessment for Manufacturing

The assessment of formaldehyde exposures resulting from manufacturing of composite wood 

products is presented in this section.

4.1.1 Description of Life Cycle Stage

The HWPW, PB, and MDF manufacturing processes include the following general steps: the 

wood components are prepared, assembled, and bonded together using resin, heat, and pressure. 

Urea-formaldehyde (UF) has historically been used in the manufacture of these CWP (USEPA 

2010a), and has recently been used in the production of most of the volumes of these CWPs

(OAQPS 1999a; OAQPS 2000a). Hot pressing cures this thermosetting resin which bonds the 

wood components into panel products (OAQPS 2000b). UF resin is synthesized from the 

reaction of urea with formaldehyde; it contains un-reacted formaldehyde and formaldehyde that 

is generated during its synthesis reaction. Also, formaldehyde may be formed as the resin cures 

during hot pressing in the CWP manufacturing process. Emissions from the CWP result from 

hydrolytic degradation of the cured resin (which is the reverse of the synthesis reaction), or from 

the un-reacted (free) formaldehyde (Tohmura 2000a); these emissions are a function of humidity

and temperature (USEPA 1996a). Currently other resins in addition to UF resin are used in the 
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manufacture of the three CWPs. Poly(vinyl acetate) (PVA) and phenol-formaldehyde (PF) 

resins are used in the manufacture of HWPW (USEPA 2010a). Melamine-urea-formaldehyde 

(MUF) and poly(methylene diphenyl diisocyanate) (pMDI) resins are used in the manufacture of 

PB and MDF and PF is used in the manufacture of PB as well (OAQPS 2000a).

The HWPW, PB, and MDF manufacturing processes are further described below with emphasis 

on aspects related to resin processing and potential sources of formaldehyde exposure. The 

market profile (USEPA 2010a) provides broad descriptions of the manufacturing processes that 

complement the descriptions given here. Most of the references used to obtain the process 

descriptions below are dated prior to 2006. In 2006, EPA implemented the National Emission 

Standards for Hazardous Air Pollutants (NESHAP) for plywood and composite wood products 

manufacturing industries. It is unknown whether any process changes were implemented in 

response to this NESHAP.

Description of HWPW Manufacturing Process

HWPW is generally made by assembling a hardwood veneer to the face and back of a core of 

veneer, lumber, particleboard, MDF, a combination of these materials, or other special cores

(USEPA 2010a).

The overall HWPW manufacturing process consists of the following steps that are presented here 

as two groups of processing steps (OAQPS 2002b):

1. Log selection, debarking, bucking (cutting), heating and then further cutting into 

veneers and drying of veneers; and

2. Adhesive mixing, veneer assembly and adhesive application, hot pressing, 

cutting, and finishing.

The two groups combined constitute the manufacturing process in log-based mills; in these mills, 

the process starts with the conversion of logs into veneer and ends with the production of 

hardwood plywood. The processing steps in the first group constitute the manufacturing process 

in a hardwood veneer plant, which are outside the scope of work because they will not be 

impacted by the FSCWPA. The processing steps in the second group constitute the 

manufacturing process in purchased veneer-based mills and 3-ply mills for which the raw 

materials are wood veneers or other platforms (USEPA 2010a).

Resin constitutes between 4.5 and eight percent of HWPW by weight (HPVA 2009a). It is 

mixed with fillers and extenders prior to application. The resin is used during the veneer 

assembly step of HWPW manufacture. In general, veneer assembly involves coating resin onto 

various plies of hardwood veneer or other materials and stacking the plies into a glue-bonded 

assembly. Most hardwood plywood mills manually lay-up their assemblies. In the majority of 

hardwood plywood mills (regardless of size), roll coaters are used to spread resin (USEPA 

2010a), and the panels are fed manually into these coaters. Generally, resin is applied to one side 

of a back or face ply and then a core ply is laid onto the resin-coated surface of the back or face 

ply. This process continues with a subsequent resin application to the core ply followed by the 

lay-up of another ply. This process is repeated until the last ply (a back or face ply) is in place

(OAQPS 2000b). An alternative to roll coaters is curtain coaters (pressure head or gravity feed), 
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spray coaters (the glue is either mixed with atomized air or directly atomized using high 

pressure), and extrusion (glue is turned into foam at 5 times its original volume and the foam is 

laid on the veneer surface in beads that are spread during pressing) (USEPA 2010a). Spray

coating occurs in spray booths. The alternative glue application systems may be used in 

automated lay-up and may allow for reduction in waste glue resulting from the operation of roll 

coaters. Other means of reduced adhesive consumption include improved process control (for 

example, avoidance of over-dried or unevenly dried veneer) and production line cleanliness (to 

allow quick identification of resin spill sources). Panel design is also a factor in reduced 

adhesive consumption (Baldwin 1995a). After application of the resin, the bundle then moves to 

a prepress or hot press pre-loader. Once pressed, the hardwood plywood then is taken to a 

finishing process where edges are trimmed and the face and back may or may not be sanded 

smooth.

The primary source of formaldehyde emissions in the HWPW manufacturing process is the 

veneer dryer (OAQPS 2002b). Emissions from dryer exhausts are may be controlled with an air 

pollution control device (OAQPS 2002b). Even when that is not so, it is likely that a dryer 

exhaust is vented through a stack. Hence, it is unknown whether this emission source results in 

worker exposure. The press is another source of formaldehyde emissions; emissions from press 

vents are typically not controlled (OAQPS 2002b). In addition to vent emissions, formaldehyde 

may be emitted from the hot press as it opens during the pressing operation (Tohmura 2000a). 

Exposure to formaldehyde may also occur while handling the HWPW or performing activities in 

proximity to the press (OAQPS 1997a; OAQPS 1998a, and OAQPS 1999b).

Description of PB Manufacturing Process

The raw materials for PB manufacturing, or furnish, are wood particles (wood chips, sawdust, 

planer shavings and other recycled materials). The manufacturing process consists of wood 

particle generation or procurement, milling, drying, and blending of the furnish with resin and 

other additives, forming the resinated material into a mat, hot pressing, and finishing (USEPA 

2010a).

In order to ensure that the resin bonds correctly with the particles, which affects both the board’s 

structural characteristics and final HCHO emissions, it is important that the furnish attain a 

specific moisture content (USEPA 2010a). The moisture content of the particles entering the 

dryer may be as high as 50 percent on a wet basis (OAQPS 2000b). The furnish is dried to a 

very low moisture content to allow for moisture gained by adding resins and other additives 

(USEPA 1996a). Dryer temperature is routinely adjusted based on furnish moisture 

measurements (OAQPS 2000b). After drying, face material, or the furnish that will be present 

on the face of a panel, may be screened for a second time to remove fines, which often absorb 

too much resin (OAQPS 2002b). The dried furnish is sent to holding bins, which provide surge 

capacity (USEPA 2010a).

From the holding bins the furnish is conveyed to blenders and mixed with resin and other 

additives. Resin is usually received on-site as a solution of 65% solids in water, stored in tanks, 

and pumped to the blenders. Additives may include wax (to impart water resistance to the 

manufactured product and reduce the tendency for equipment plugging), catalyst (to accelerate 

resin cure and reduce press time), and scavengers for reduction of emissions from the process 
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and the manufactured product (USEPA 1996a; OAQPS 2000b; USEPA 2010a, and Maloney

1993a). Furnishes are generally no warmer than 100 F when blended to avoid pre-curing and 

drying out of the resin (USEPA 1996a). The furnish may be sampled before and after blending 

to ensure proper moisture control (OAQPS 1998c).

The dominant type of blender consists of a small horizontal drum with high-speed, high shear 

impellers (USEPA 1996a; Maloney 1993a). Resin and its additives are sprayed through air or 

airless atomizing nozzles or applied by centrifugal atomization. In the air spray system, the 

supplied air must be exhausted from the blender but in the airless systems the elimination of 

atomizing air eliminates the associated air pollution problem. Additionally, because of the high 

speed and number of its impellers, the blender, especially when not fully loaded with furnish, can 

act as an axial-type fan and discharge air causing dusting problems; this may be limited by

restricting its air intake (Maloney 1993a). Most blenders vent through baghouses (OAQPS 

2000b). Blenders generally are designed to discharge the resinated particles into a plenum over a 

belt conveyor that feeds the blended material to a forming machine (OAQPS 2000b). In some 

installations, this plenum is vented back to the blender for recirculation of fines while in other 

installations it is vented to the suction side of the forming machine (Maloney 1993a). Some 

evaporation of moisture (and hence formaldehyde as well) from the furnish may occur from air 

exposure when conveyed from the blenders to the forming station (USEPA 1996a).

After the blending process, the resinated material is fed to the forming machine that deposits the 

blended material into a continuous mat. To produce multilayer particleboard, several forming 

heads can be used in series, or air currents can produce a gradation of particle sizes from face to 

core (OAQPS 2002b). Most formers vent to a baghouse (OAQPS 2000b). The formed mat is 

pre-pressed (optional), cut into desired lengths, and conveyed to the hot press. Few presses are 

vented to an air pollution control device and some of these presses are fully enclosed (OAQPS 

2000b). After pressing, the particleboard panels are cooled, sanded, trimmed to desired final 

dimensions, and may undergo other finishing operations. Emissions from most coolers are not 

controlled and some coolers whose emissions are controlled are fully enclosed.

The primary sources of formaldehyde emissions are the dryers, hot presses, board coolers and 

blenders (OAQPS 2002b).

Description of MDF Manufacturing Process

The raw materials for MDF manufacturing consist of wood chips, sawdust, planer shavings and 

other recycled materials which are typically delivered from off-site locations. The 

manufacturing process consists of pulping the raw material to fibers in a refiner, drying, blending 

the fibers with resin and additives, forming the resinated material in a mat, pressing, and 

finishing (OAQPS 2002b; USEPA 2010a).

Raw material is processed through a steam pressurized refiner which discharges through a blow 

valve into a blowpipe that is connected to a tube dryer (USEPA 1996a; OAQPS 2000b, and 

USEPA 2010a). The pressurized refiner may also vent into the tube dryer. The tube dryers are 

directly fired or indirectly heated. Dryer inlet temperature are on average as high as 270°F. The 

wood fiber is pneumatically drawn through the tube dryers and is separated from the dryer 

exhaust gas in a cyclonic collector. The dried wood fibers are discharged from the cyclonic 
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collectors through air locks into dry storage bins which provide surge capacity. The dryer gas 

exhaust may be vented to an air pollution control device, including incineration based controls or 

scrubbers (OAQPS 2000b; USEPA 2010a). Most mills blend resin, wax and other additives by

injection into the blowline where they readily mix with the fibers under the turbulent flow 

conditions present in the bowline. This occurs prior to the drying of the fiber in the tube dryer 

but some mills use mechanical blending that applies the additives to the dried fiber (USEPA 

2010a). The blowline system is more frequently used because it is fully enclosed, thereby 

reducing worker exposure and has superior blending performance. However, the resin may lose 

some reactivity as a result of the hot, wet environment in the blowline tube and therefore a higher 

resin-to-fiber ratio is required as compared to the conventional blender system. Based on a 1998 

site visit report to the Medite Division of Sierra Pine MDF plant, the plant personnel stated that 

methylene diphenyl diisocyanate (MDI) resins are always added using the blowline system due 

to potential worker exposure concerns (OAQPS 1998b).

The resinated fibers are conveyed from the dry storage bin, where they are deposited as a mat on 

a continuously moving screen system (OAQPS 2002b). Most formers vent to a baghouse 

(USEPA 1996a). The deposited mat is pre-pressed and sometimes pre-trimmed prior to 

transferring to the hot press. Hot pressing activates the thermosetting resin and bonds the 

resinated material into a solid panel. The press may be vented to an air pollution control device, 

including incineration based controls, scrubbers or a baghouse (OAQPS 2000b). Additionally, 

the press area may be partially or fully enclosed and may be vented with fans (OAQPS 2002a). 

Based on non-CBI responses from the 1998 information collection request, seven of the 21 

presses were fully enclosed at MDF manufacturing facilities (OAQPS 2000a). After hot 

pressing, the panels are cooled and finished. The board cooler may be vented to incineration 

based controls and additionally the cooler may be fully enclosed in a vented enclosure (OAQPS 

2000b). Finishing operations include sanding, trimming, and sawing.

The primary sources of hazardous air pollutant (HAP) emissions (including formaldehyde 

emissions) at MDF plants include emissions from pressurized refiners, wood dryers, blenders, 

formers, presses, and board coolers; the finishing operations may also be a source of HAP 

emissions (OAQPS 2000b). The largest emission sources are wood dryers and press vents. 

Formaldehyde emissions are significantly higher after resin application. For example, dryer 

emissions from a blowline system are much higher than the dryer emissions from a conventional 

blender system due to the presence of formaldehyde-based resin in the wood material in the 

former dryer system. While fugitive emissions from the blender, former, and cooler may occur, 

these emissions are much lower and are typically not controlled (OAQPS 2002b).

4.1.2 Production Volumes and Number of Establishments, Workers, Production Hours, and 

Work Days

The domestic production volumes and number of sites, or mills, for the manufacture of the three 

composite wood products are given in Table 4-1 and Table 4-2. These data are provided for 

reference purposes only and are not used in the assessment. These tables present data on the 

number of mills from the Composite Panel Association (CPA) (AWFS 2009a) and the U.S. 

International Trade Commission (USITC) (USITC 2008a). The number of mills reported by the 

2007 Economic Census (Census 2007a) is presented in Table 4-3. The U.S. Census reported a 

greater number of mills for both NAICS codes than the CPA and USITC sources. Note that the 
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U.S. Census classifies PB and MDF manufacture under a single NAICS code: 321219 –

Reconstituted Wood Product Manufacturing. This NAICS code also includes fiberboard, 

hardboard (HB), oriented-strand board (OSB), waferboard, flakeboard, and chipboard, which are 

outside of the scope of the assessment. Similarly, NAICS code 321211 - Hardwood Veneer and 

Plywood Manufacturing includes the manufacture of hardwood veneers, which are outside the 

scope of the assessment (see Section 2). Therefore, the number of mills data for both 

manufacturing NAICS codes represent mills that manufacture products outside the scope of this 

assessment.

Estimates for the total number of workers and aggregate production hours worked for the 

manufacturing of the three composite wood products were obtained from the EPA market profile

(EPA 2010a) and the 2007 Economic Census (Census 2007a) and are presented in Table 4-3. 

The 2007 Economic Census data are likely an overestimate of the number of workers for the 

following reasons:

 Trade associations reported that mills have closed down; and

 NAICS codes 321219 – Reconstituted Wood Product Manufacturing and 321211 

- Hardwood Veneer and Plywood Manufacturing both include products outside 

the scope of this assessment.

However, it is assumed that the census data on number of workers and aggregate production 

hours worked are proportionally overestimated such that their ratio, used to calculate production 

hours per day and days per year, is representative of mills within the scope of the assessment.

Using these data, the average production days per year per worker (assuming eight hours per 

day), and average production hours per day per worker (assuming 250 days per year) were 

calculated, and the results are given in Table 4-3. These calculated values are compared to the 

OPPT default values. As default, OPPT assumes people work five days per week and 50 weeks 

per year (with two weeks of vacation), which results in 250 work days per year. OPPT also 

assumes a typical work day is eight hours per day. As seen in Table 4-3, the calculated 

production days per year (assuming 8 hours per day) do not deviate from the OPPT default value 

for frequency of exposure of 250 days per year by more than 10 percent. Based on this 

comparison, the frequency of exposure for manufacturing is assessed as 250 days per year. 

Similarly, all of the calculated values for production hours per day (assuming 250 days per year) 

do not deviate from the OPPT default value for duration of exposure of 8 hours per day by more 

than 10 percent. Based on this comparison, the duration of exposure for manufacturing is 

assessed as 8 hours per day.

Table 4-1. U.S. Hardwood Plywood Production Data and Number of Mills

Hardwood Veneer and 

Plywood Mill

Composite Wood 

Product Type

2008 U.S. Production Volume of 

Composite Wood Product

(thousands of ft2)

1

Number of U.S. 

Mills2

Hardwood Plywood Mills Hardwood Plywood 748,400 24

1 U.S. production volume data obtained from personal communication with HPVA (HPVA 2009a). The 

plywood thickness basis was not provided.

2 Number of U.S. mills obtained from the U.S. International Trade Commission report on wood flooring and 

hardwood plywood (USITC 2008a).
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Table 4-2. U.S. Reconstituted Wood Product Production Data and Number of Mills

Reconstituted Wood 

Product Mill Type

Composite Wood 

Product Type

2007 U.S. Production Volume of Composite 

Wood Product (thousands of ft2at 3/4" 

thickness basis)1

Number of 

U.S. Mills2

Particleboard Mills Particleboard 3,542,666 34

Medium-Density 

Fiberboard Mills

Medium-Density 

Fiberboard 1,884,264 27

1 U.S. production volume data obtained from the 2007 North American Downstream Market Report (CPA 2008a).

2 Number of U.S. mills obtained from “Update on California’s Composite Wood Products Regulation” presented 

at AWFS Show in Las Vegas, NV on July 18, 2009 provided by CARB to EPA (AWFS 2009a). The presentation 

was co-presented by CARB and CPA. The number of MDF mills is a high-end estimate that may include some 

hardboard mills: the presentation did not differentiate between non-CPA-member MDF and HB mills.

Table 4-3. Summary of 2007 Economic Census Data and Exposure Frequency and 

Duration Calculated from These Data for U.S. Manufacturing Mills

2007 Economic Census Data

Parameters Calculated 

from the Corresponding 

2007 Economic Census 

Data

NAICS 

Code

NAICS 

Industry 

Description

Number of 

Establishments

Maximum 

Number of 

Production 

Workers

Aggregate 

Production 

Hours 

Worked 

(hours)

Average 

Production 

Days per 

Year 

(assuming 8 

hours/day)

Average 

Production 

Hours per 

Day 

(assuming 

250 

days/yr)

321219

Reconstituted 

wood product 

manufacturing

262 16,076 34,615,000 269 8.61

321211

Hardwood 

veneer & 

plywood 

manufacturing

304 15,504 32,256,000 260 8.32

Source: EPA market profile (USEPA 2010a) and 2007 Economic Census (Census 2007a).

4.1.3 Pre-Baseline Exposure Monitoring Data

This section presents a summary of the inhalation exposure monitoring data collected from 

OSHA IMIS for the period 2002 to 2009 on the manufacture of HWPW, MDF, and PB as well as 

a summary of the other compiled inhalation exposure monitoring data on CWP manufacturing.

Table 4-4 provides the maximum, median, and minimum 8-hour TWA personal inhalation 

monitoring formaldehyde concentrations by worker activity category for the manufacture of 

HWPW from OSHA IMIS. Table 4-5 provides the maximum, median, and minimum 8-hour 

TWA personal inhalation monitoring formaldehyde concentrations by worker activity category 

for the manufacture of reconstituted wood products, including PB and MDF from OSHA IMIS.
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Table 4-4. Summary of Formaldehyde Inhalation Monitoring Data for Hardwood Plywood Manufacturing Mills from the OSHA 

IMIS Database

Worker 

Activity 

Description

Total 

Number of 

Sites where 

Monitoring 

Occurred

Total 

Number 

of Data 

Points

Monitored Formaldehyde Concentration1

Year Monitoring Occurred for the Summary 

Data Points

Maximum Median Minimum Maximum 

Concentration

Median 

Concentration2

Minimum

(ppm) (μg/m Concentration 3) (ppm) (μg/m3) (ppm) (μg/m3)

Press 

Operation 2 4 1.56 1,917.2 0.695 854.2 0.213 261.8 2003 2003 / 2003 2006

Glue 

Spreading 2 2 0.32 393.3 0.28 344.1 0.24 295.0 2003 2003 / 2006 2006

Mixing 

Adhesive 1 1 0.119 146.3 0.119 146.3 0.119 146.3 2006 2006 2006

Lathe 

Operation 1 1 0.022 27.0 0.022 27.0 0.022 27.0 2004 2004 2004

Production 

Laborer or 

Other Operator

2 4 0.142 174.5 0.0695 85.4 0.021 25.8 2007 2004 / 2007 2004

Overall 

Statistics for 

All Data 

Points

4 12 1.56 1,917.2 0.1775 218.1 0.021 25.8 2003 2006 / 2007 2004

1 The formaldehyde concentration in μg/m3 was calculated from the provided concentration in ppm by multiplying the concentration in ppm by 1,229 μg/m3

/ppm

(see Appendix E).

2

For worker activities with an even number of data points, the median was calculated as the average of the two middle values. The years are provided for the two 

middle values.
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Table 4-5. Summary of Formaldehyde Inhalation Monitoring Data for Reconstituted Wood Product Manufacturing Mills from the 

OSHA IMIS Database

Worker

Activity

Description

Total 

Number of 

Sites where 

Monitoring 

Occurred

Total 

Number 

of Data 

Points

Monitored Formaldehyde Concentration1

Year Monitoring Occurred for the Summary Data 

Points

Maximum Median Minimum

Maximum 

Concentration

Median 

Concentration2

Minimum

(ppm) (μg/m Concentration 3) (ppm) (μg/m3) (ppm) (μg/m3)

Press 

Operation 1 3 0.12 147 0.089 109 0.009 11 2005 2005 2005

Production 

Laborer or 

Other 

Operator and 

CSHO

4 6 0.243 299 0.043 53 0.02 25 2005 2006 / 2005 2006

Overall 

Statistics for 

All Data 

Points

4 9 0.243 299 0.051 62.7 0.009 11 2005 2005 2005

1 The formaldehyde concentration in μg/m3 was calculated from the provided concentration in ppm by multiplying the concentration in ppm by 1,229 μg/m3

/ppm

(see Appendix E).

2

For worker activities with an even number of data points, the median was calculated as the average of the two middle values. The years are provided for the two 

middle values.
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Appendix H presents additional historical exposure monitoring data from a variety of studies and 

reports. These data are briefly summarized here for reference purposes. Note that these data 

include studies from countries other than the United States and their relevance to U.S. mills has 

not been established.

Plywood Manufacturing Mills Monitoring Data

Sampling data6collected in British Columbia from 1992 to 2003 indicate that formaldehyde 

levels in the plywood manufacturing industry are predominantly below 0.3 ppm (WorksafeBC 

2009a). Other data indicate an exposure range of 0.08 ppm to 0.60 ppm (Fransman 2003a) in the 

plywood manufacturing sector.

Short-term exposure levels and instantaneous ceiling limit values for plywood manufacturing 

available from one discussion paper (WorksafeBC 2009a) ranged from 0.14 to 0.29 ppm and 

0.33 to 0.44 ppm, respectively, in a 2002 survey.

MDF Manufacturing Mills Monitoring Data

For MDF manufacturing, the highest estimated geometric mean for ambient formaldehyde levels 

was reported as 0.43 ppm in the main production area of manufacturing facilities in Quebec 

(Lavoue 2005a). In one study (Chung et al. 2000a), free formaldehyde levels were determined to 

be less than 0.14 ppm during machining of the Class B (higher formaldehyde potential) MDF.

According to one Swedish report, formaldehyde levels were at 0.2 ppm (arithmetic mean) 

between 1980 and 1989 in facilities manufacturing MDF (IARC 1995a). 

Particleboard and Fiberboard Manufacturing Mills Monitoring Data

Time-weighted average (8-hour) levels of formaldehyde have been noted to be generally higher 

than 0.3 ppm in sampling data collected over a period of 15 years (1990 to 2005) for 

particleboard and fiberboard manufacturing in British Columbia, Ontario, Quebec, and the 

Netherlands (WorksafeBC 2009a). Exposures in fiberboard manufacturing ranged from 0.07 to 

5.0 ppm for samples taken between 1996 and 2000 (WorksafeBC 2009a). Exposure levels from 

between 0.1 and 0.4 ppm (Quebec) (Lavoue 2005a) to 1.15 ppm (Scandinavia) (Niemelä and 

Vainio 1981a) have been noted in other studies of the particleboard and MDF manufacturing 

industry.

Eight-hour TWA levels of formaldehyde ranging from 0.07 to 0.20 ppm and instantaneous 

ceiling values that were as high as 7.47 ppm were reported in particleboard manufacturing plants 

in 2002 (WorksafeBC 2009a). A median of 0.62 ppm was observed for particleboard workers in 

measurements taken in 1987/1988 (Horvath et al. 1988a) and a value of 0.3 ppm was reported for 

particleboard manufacture between 1980 and 1989 (IARC 1995a).

 

6

Includes 500 samples collected from identifiable sources of formaldehyde in a number of industries, including the 

plywood industry where workers are exposed to formaldehyde as a by-product (e.g., off-gassing of the substance 

during the curing process of urea-formaldehyde glue in a plywood plant)”. WorkSafeBC does not specify whether 

the exposure in plywood plants was strictly caused by using UF resins. These samples may be taken at both 

hardwood and softwood plywood plants.
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For particleboard manufacturing, formaldehyde exposure levels in the range of 0.08 to 0.9 ppm, 

with peaks reaching 4.1 ppm, were observed from measurements taken between 1975 to 1983 

(Edling 1988a). Mean levels between 0.4 and 2.3 ppm have been reported for particleboard 

manufacture by other researchers between 1975 and 1984 (Kauppinen and Niemelä 1985a). A 

mean level less than 1 ppm and a maximum level of 1.4 ppm during particleboard manufacture 

were also reported in 1982 (Preuss et al. 1985a).

Occupational hygienists from WorkSafeBC sampled different locations in a fiberboard plant in 

British Columbia from January to June 2006 and found formaldehyde levels ranging from 0.03

to 1.19 ppm. The highest exposure was in the press outfeed area, ranging from 0.32 to 1.19 ppm. 

4.1.4 Respiratory Protection Usage During Manufacturing

Since OSHA IMIS data do not provide information on personal protective equipment use, OSHA 

inspection reports associated with the IMIS data were examined to get an idea of the use of 

respiratory protection by workers when engaged in manufacturing activities. Appendix G

presents a summary of each reviewed inspection report.

The nine TWA, personal monitoring IMIS data points for PB and MDF manufacturing in Table 

4-5 discussed in Section 4.1.3 are associated with four inspections. Of these four inspections, a 

total of two inspection reports for PB and MDF manufacturing facilities were requested from 

OSHA. One of the two inspection reports (inspection number 307061689; see Appendix G), 

which accounts for four of the nine TWA, personal monitoring IMIS data points, has been 

received and reviewed, but the other inspection report was no longer available due to its age. 

Additionally, two other inspection reports were requested from inspections prior to 2002 and 

hence are not associated with the nine data points discussed above. One of these two inspection 

reports (inspection number 303864029; see Appendix G) has been received and reviewed, but

the other inspection report was no longer available due to its age. Finally, an additional 

inspection report (inspection number 312479835; see Appendix G) associated with the CWP 

fabrication IMIS data (see Section 4.2.3) was requested, received, and reviewed. Although the 

facility was identified in IMIS by a fabricator NAICS code, the inspection report states that the 

facility manufactures MDF and then fabricates flooring from the MDF. As the monitored 

workers were associated with the manufacture of MDF, this inspection report is discussed in this 

section and Appendix G with the manufacturer inspection reports.

Of the three reviewed inspection reports, only one report for a facility that manufactures MDF 

primarily for flooring indicated the use of respirators by production workers (press assistants)

(inspection number 312479835; see Section 4.2.4 and Appendix G). The workers were observed 

wearing 3M 6300 half masks with formaldehyde cartridges and had the option to use fullfacepiece respirators. The two TWA measurements taken for press assistants were both below 

the PEL of 0.75 ppm, although one exceeded OSHA’s TWA action level (AL) of 0.5 ppm for 

formaldehyde. The two facilities associated with the remaining two inspection reports had TWA 

measurements below the action level.

The 12 TWA, personal monitoring IMIS data points for HWPW manufacturing in Table 4-4

discussed in Section 4.1.3 are associated with four inspections. None of these four inspection

reports for HWPW manufacturing facilities were requested from OSHA. However, two 
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inspection reports for HWPW manufacturing facilities were requested from inspections prior to 

2002 and hence are not associated with the 12 data points discussed above. Both of these 

inspection reports have been received and reviewed. Neither report indicated the use of 

respiratory protection. The first facility had four TWA measurements and three STEL 

measurements (inspection number 303713325; see Appendix G). All four TWA measurements 

were below the action level and all three STEL measurements were below the OSHA STEL of 2 

ppm. The second facility had ten TWA measurements and six STEL measurements (inspection 

number 123445595); see Appendix G). All STEL measurements were below the OSHA STEL 

of 2 ppm. Two of the TWA measurements were above the OSHA AL but below the PEL; the 

remainder were below the action level. This facility was cited by OSHA for formaldehyde 

overexposure. The inspection report noted that workers were not observed wearing respiratory

protection during the inspection.

Although one inspection report (inspection number 123445595; see Appendix G) for HWPW 

manufacturing noted that workers were not wearing respirators in spite of exposure levels that 

exceeded the AL (but were below the PEL), respirator use has been noted in another case in 

MDF manufacturing (inspection number 312479835; see Appendix G) when exposure levels 

exceeded the AL (but were below the PEL). The need to protect against chemicals and 

particulates other than formaldehyde might also dictate respirator use. Therefore, the reported 

use of respirators in the inspection report for the MDF manufacturing facility could have been 

for protection against chemicals other than formaldehyde or it could be a precautionary practice. 

Overall, the limited number of inspection reports that were available and examined does not 

provide conclusive evidence that respirators are necessarily worn by workers when their 

exposure meets or exceeds the formaldehyde AL or PEL.

4.1.5 Baseline Exposure and the Effect of Analytical Options on Baseline Exposure for 

Manufacturing

Baseline exposures and exposures for the analytical options were not assessed quantitatively due 

to data gaps. The emission rate data for CWPs presented in Appendix D apply to the CWPs after 

their manufacture. Hence, these emission rates are only relevant to the manufacturing process 

after the pressing operation and are not applicable to the remainder of the process, which 

includes unit operations in which uncured resins are present and the press. These sources of 

formaldehyde cannot be assumed negligible in manufacturing mills. As indicated in the prebaseline OSHA IMIS monitoring data presented in Section 4.1.3, formaldehyde exposures have 

been observed associated with mixing and applying adhesives and pressing operations. The 

literature search did not yield information on modeling indoor air concentrations from these 

sources. Therefore, exposures during baseline and analytical options are assessed qualitatively.

At baseline, approximately all domestic production of HWPW, MDF, and PB will be in 

compliance with the CARB ATCM Phase 2 standard, as shown in Table D-3 in Appendix D. 

Only small fractions of HWPW and PB domestic production will not be in compliance with the 

CARB ATCM Phase 2 standard at baseline.

Approximately 0.28% of domestic HWPW production will not be in compliance with any CARB 

ATCM standard. However, the emission level of this fraction of HWPW production is estimated 
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to be 0.058 ppm, which is close to the CARB ATCM Phase 2 standard of 0.05 ppm and less than 

the CARB ATCM Phase 1 standard of 0.08 ppm for HWPW.

7

Approximately 2% of domestic PB production will not be in compliance with the CARB ATCM 

Phase 2 standard.7 Of this 2% of domestic PB production, approximately 0.2% of domestic PB 

production will not meet any CARB ATCM emission standard. However, the emission level of 

this 0.2% of domestic PB production is estimated to be 0.058 ppm, which is less than the CARB 

ATCM Phase 2 standard of 0.09 ppm for PB. Additionally, approximately 1.8% of domestic PB 

production will be in compliance with the CARB ATCM Phase 1 standard with an estimated 

emission level of 0.09 ppm. Hence, the CARB Phase 1 and FSCWPA/CARB Phase 2 analytical

options will result in a negligible effect on baseline exposure levels for manufacturing. Since 

approximately all domestic production of CWPs are expected to meet the CARB ATCM Phase 2 

standard at baseline, only the NAF analytical option will affect baseline exposures.

NAF resins do not contain any formaldehyde. Therefore, mills that use NAF resins in 

compliance with NAF standards should achieve a reduction in formaldehyde exposures due to 

the elimination of the formaldehyde content of resins. However, wood naturally emits 

formaldehyde, and it is possible that workers in mills that use only NAF resins may still 

experience some formaldehyde exposures due to the natural emission of formaldehyde from 

wood. Other sources of formaldehyde can exist for mills that apply value-added surfaces. 

However, it is uncertain how many mills apply value-added surfaces.

4.1.6 Dermal Exposures during Manufacturing

Dermal exposures to workers during manufacturing can occur during unloading of liquid UF 

resin. The free formaldehyde content immediately after manufacture is approximately 0.59% but 

reduces to 0.15% after 24 hours (Fink 2005a). For the purpose of this assessment, EPA assumes 

a formaldehyde concentration of 0.59% in the UF resin.

The EPA/OPPT 2-Hand Dermal Contact with Liquid Model estimates a dermal exposure of 590

to 1,800 mg/day for exposure to a chemical at 100% concentration. For the assumed 

formaldehyde concentration of 0.59%, the model estimates worker exposure of 3.5 to 10.6 

mg/day. This results in an estimated dose of 0.05 to 0.15 mg/kg/day for an average 70 kg 

worker.

The source (Fink 2005) does not specify whether the provided free formaldehyde contents in UF 

resins are specific to UF resins for CWPs or other applications. Additionally, Fink (2005) does 

 

7 The EPA market profile (USEPA 2010a) indicates that at baseline 0.1% of the volume of U.S. consumed HWPW 

will be domestically-produced and will have an emission level not meeting the emission standards. The remainder of 

the U.S. consumed domestically-produced HWPW will have shares of 19.7% of U.S. HWPW consumption (meeting 

CARB Phase 2) and 16.2% of U.S. HWPW consumption (meeting NAF). Therefore, the volume fraction of 

domestically-produced HWPW not meeting any emission standard and relative to the total volume of U.S. 

consumed domestically-produced HWPW is 0.1% / (0.1% + 19.7% + 16.2%) x 100% = 0.28%. Similarly, at 

baseline 0.2% of the volume of U.S. consumed PB will be domestically-produced and will not meet any emission 

standard. The remainder of the U.S. consumed domestically-produced PB will have shares of 1.7%, 85.0%, 3.0%, 

and 7.1% (meeting CARB Phase 1, CARB Phase 2, ULEF, and NAF, respectively). Therefore, the volume fraction 

of domestically-produced PB exceeding CARB Phase 2 relative to the total volume of U.S. consumed domesticallyproduced PB is (0.2% + 1.7%) / (0.2% + 1.7% + 85.0% + 3.0% + 7.1%) x 100% = 2.0%.
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not specify the statistical significance of the formaldehyde contents, such as being typical, 

maximum, minimum, etc. This assessment assumes these formaldehyde contents are typical for 

UF resins specific for CWPs and representative of pre-baseline conditions. Additionally, it is 

uncertain how the free formaldehyde content of CWP resins will change as manufacturers adopt 

the CARB ATCM limits. The source (Fink 2005) is from 2005 and may not represent resins at 

baseline or analytical options. Therefore, both baseline dermal exposures and the effect of 

analytical options on baseline dermal exposures are uncertain and cannot be estimated.

4.2 Exposure Assessment for Composite Wood Product Fabrication

The assessment of formaldehyde exposures resulting from the use of the three composite wood 

products (CWPs) in composite wood product fabrication is presented in this section.

4.2.1 Description of Life Cycle Stage

A general description of the manufacturing process is presented below. The literature search did 

not yield detailed information on the manufacture of specific composite wood fabrication 

products (downstream products). The Office of Enforcement and Compliance Assurance 

(OECA) sector notebook Profile of the Wood Furniture and Fixtures Industry (OECA 1995a) 

provides a general process description for wood furniture and fixtures constructed from raw 

lumber, which does not include composite wood products. Activities involved in fabrication of 

wood furniture from raw lumber include drying raw wood; sawing into appropriate sizes, planing 

and bending (i.e., machining); assembling the wood material into parts; sanding; prefinishing 

(e.g., watering, sanding, derosination, bleaching); coating by spraying, brushing, or dipping; and 

finishing (OECA 1995a). As described below, similar activities are used to produce furniture 

and fixtures from the composite wood products that are the focus of this assessment.

The following activities (unit operations) are typically used to manufacture wood products, based 

on a survey of Georgia wood products manufacturers (GDNR 1996a). Although the reference 

does not describe if the surveyed manufacturers used composite wood products or raw lumber, it 

explains that wood product manufacturers may use similar processes to produce different 

products using different raw materials. Therefore, the cited activities are likely used to 

manufacture downstream products using composite wood products as raw materials. The cited 

activities include the following:

 Application of overlays or decorative surfaces (other than wood or woody-grass 

veneers)8;

 Assembling;

 Gluing;

 Spray application;

 Painting and coating;

 Water-based coating;

 Solvent-based coating;

 

8 The application of wood or woody-grass veneers on CWPs is described as HWPW manufacturing in FSCWPA and 

therefore is not included here as a part of CWP fabrication even though this activity may occur in CWP fabrication 

sites.
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 Staining;

 Sealing;

 Water-based cleaning; and

 Solvent-based coating.

These process activities apply to the following CWP fabrication sectors: millwork, cabinet 

makers, veneer plywood, trusses, prefabricated construction, particleboard and reconstituted 

wood, wood furniture, miscellaneous furniture, exhibits and showrooms (GDNR 1996a). 

Workers are potentially exposed to formaldehyde during the above-listed activities from 

unfinished and finished (e.g., overlayed, coated, or painted) composite wood products. 

However, emission rates from the finished products are generally lower than those from the 

unfinished products (Battelle 1996a).

Additionally, the following materials, which are used in CWP fabrication, may also be a 

potential source of formaldehyde exposure during CWP fabrication:

 Adhesives used in gluing and overlaying barrier surfaces;

 Overlay materials; and

 Coatings and varnishes used in finishing operations.

Formaldehyde-based adhesives may be used in upholstered furniture manufacturing based on the 

contents of an OSHA inspection report associated with the compiled IMIS data (OSHA 2003a). 

At the inspected site, formaldehyde-based adhesive is mixed and applied by hand to glue wood 

sections together. The inspection report noted that proper PPE was not used during this activity 

and formaldehyde sampling results were below the action level (OSHA 2003a; see Appendix G). 

Workers also use a formaldehyde-based adhesive with a pneumatic gun to assemble wooden 

chairs. Workers wear a half-face respirator while assembling the wooden chairs, although the 

inspection report stated past air sampling indicated formaldehyde levels were below the PEL

(OSHA 2003a; see Appendix G).

During the application of overlay materials, adhesive is applied to the decorative overlay, and the 

overlay and the substrate (composite wood product) are subsequently bonded through a pressing 

operation. Based on information associated with similar activities that occur during 

manufacturing of composite wood products, it is inferred that formaldehyde vapor would be 

emitted during glue application and hot pressing, resulting in potential for inhalation exposure. 

Some overlay materials do not require additional adhesive to be bonded with the wood substrate 

as they are saturated with reactive resins and partially cured as supplied (CPA 2007a). The 

overlays may be saturated with formaldehyde-based resins and thereby serve as another source 

of formaldehyde. A CPA technical bulletin indicates that several types of adhesives may be used 

for the application of overlays to PB and MDF, such as hot melt adhesives, PVA, acrylic-based 

formulations, UF, PF, and MF resins (CPA 2007a).

The finishing operation for wood furniture and cabinets includes the application of several clear 

and/or color coatings. The coating process may be manual or automatic. The most common 

manual techniques are wiping, dipping and spraying via spray guns. Automatic application 

techniques include robotic spraying, roll coating and curtain coating. While spraying and 

coating processes typically occur in ventilated booths equipped with dry filters to control 
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particulates (USEPA 2000a), workers inside the booth can be significantly exposed if they are 

located in the direction of flow of the coating mist (IRSST undated). An OSHA inspection 

report indicates the use of formaldehyde-based coating in the finishing of wood cabinets. The 

employer provided respirators to reduce worker exposure to formaldehyde from the coating 

(OSHA 2008a; see Appendix G). OSHA offers guidance on safe practices in the woodworking 

industry through its Woodworking eTool (OSHA 2002a). OSHA recommends using ventilated, 

automated systems for applying coatings and adhesives when feasible. OSHA also recommends 

that manual spray operations be performed in a spray booth or separate, ventilated area. Dip 

coating should be ventilated with an enclosure or capture hood. The prevalence of the 

engineering controls described in the OSHA Woodworking eTool is unknown. In addition to the 

Woodworking eTool, OSHA has a standard for spray finishing operations (29 CFR 1910.107), 

which provides detailed requirements for the design and construction of spray booths and rooms 

(OSHA 2002a).

Some information is available on the amount of natural wood products and composite wood 

products outside the scope of this assessment in fabricator sites. According to the EPA market 

profile (USEPA 2010a), natural wood products and composite wood products outside the scope 

of this assessment (e.g., hardboard) may be used in the composite wood fabrication sectors. 

While the three composite wood products within the scope of work have the highest 

formaldehyde emission rates, the relative contribution to overall exposure of these other wood 

products may be considerable if they are present at a site in large quantities relative to the three 

composite wood products. Tables 6-4 through 6-20 in the EPA market profile (USEPA 2010a) 

provide the value of raw materials in each of the sectors. For the following sectors, the other 

composite wood products (such as softwood plywood and hardboard) comprise 10% or greater 

of the total composite wood product material costs, and therefore, could be present in significant 

quantities relative to HWPW, PB and MDF:

 Wood window and door manufacturing (NAICS code 321911);

 Other millwork (including flooring) (NAICS code 321918);

 Manufactured home (mobile home) manufacturing (NAICS code 321991);

 Upholstered household furniture manufacturing (NAICS code 337121);

 Wood television, radio, and sewing machine cabinet manufacturing (NAICS code 

337129); and

 Showcase, partition, shelving, and locker manufacturing (NAICS code 337215).

Therefore, for these sectors, other composite wood products may contribute to overall exposure. 

However, this analysis is based only on the costs of the materials and not on the actual volumes 

of the materials. Data on actual volumes consumed per sector and data to convert material costs 

to material volumes were not available.

The information above indicates the possibility of the existence of potential formaldehyde

exposure sources other than the composite wood products of interest. The relative significance 

of these other sources is not known. For example, the extent to which formaldehyde-containing 

coatings are used in CWP fabrication is not known and where such materials are used, the extent 

to which engineering controls such as ventilated spray booths are used to control exposure is also 

not known.
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4.2.2 Number of Establishments, Workers, Production Hours, and Work Days

Estimates for the number of establishments, total number of workers, and aggregate production 

hours worked for each of the industry sectors that comprise the composite wood product 

fabrication life cycle stage were obtained from the 2007 U.S. Economic Census (Census 2007a), 

and are presented in Table 4-6. It is uncertain whether all sites within each identified NAICS 

sector use the composite wood products of interest. Therefore, the number of sites and workers 

identified in Table 4-6 may represent facilities that do not use composite wood products and are 

considered maximum values. Using these data, the average number of workers per site, average 

production days per year per worker (assuming eight hours per day), and average production 

hours per day per worker (assuming 250 days per year) were calculated, and the results are given 

in Table 4-6. As seen in Table 4-6, all of the calculated values for production days per year 

(assuming 8 hours per day) do not deviate from the OPPT default value for frequency of 

exposure of 250 days per year by more than 10 percent. Based on this observation, the 

frequency of exposure for composite wood fabrication in general is assessed to be 250 days per 

year. Similarly, all of the calculated values for production hours per day (assuming 250 days per 

year) do not deviate from the OPPT default value for duration of exposure of 8 hours days by

more than 10 percent. Based on this observation, the average duration of exposure for composite 

wood fabrication in general is assessed to be 8 hours per day.

The result for duration of exposure of 8 hours per day derived from aggregate census data is 

supported by duration data given in IMIS. For all composite wood product fabrication industries 

identified in Table 4-6 and all exposure types (e.g., TWA, STEL), 182 exposure data points 

(sampled in the year 2002 through 2009) were collected. These 182 data points have the 

following exposure duration data9:

 Exposure durations of blank, “daily”, or other frequency estimate without a 

duration estimate: 88 data points (48%);

 Exposure durations of eight hours per day: 80 data points (44%);

 Exposure durations of less than eight hours per day: 10 data points (5%); and

 Exposure durations of greater than eight hours per day: four data points (2%).

 

9

 Note: percentages should add to 100 percent but may not due to rounding.
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Table 4-6. Summary of 2007 Economic Census Data and Exposure Frequency and Duration Calculated from These Data for 

Composite Wood Product Fabricating Sites

2007 Economic Census Data

Parameters Calculated from the Corresponding 

2007 Economic Census Data

NAICS Code

NAICS 

Industry 

Description

Maximum 

Number of 

Establishments

Maximum 

Number of 

Production 

Workers

Maximum Aggregate 

Production Hours 

Worked 

(thousands of hours)

Average 

Production 

Workers per 

Site 

Average 

Production 

Days per Year 

Per Worker 

(assuming 8 

hours/day)

Average 

Production 

Hours per 

Day Per 

Worker 

(assuming 250 

days/yr)

321911

Wood Window

and Door 

Manufacturing

1,494 62,089 116,209 42 234 7.49

321918

Other Millwork 

(including 

flooring) 

Manufacturing

2,101 34,394 68,475 16 249 7.96

321991

Manufactured 

Home (mobile 

home) 

Manufacturing

376 32,010 60,725 85 237 7.59

321999

All Other 

Miscellaneous 

Wood Product 

Manufacturing

1,964 27,952 54,290 14 243 7.77

337110

Wood Kitchen 

Cabinets and 

Countertop 

Manufacturing

9,683 107,206 213,487 11 249 7.97

337121

Upholstered 

Household 

Furniture 

Manufacturing

1,633 60,721 118,966 37 245 7.84
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Table 4-6 Continued

2007 Economic Census Data

Parameters Calculated from the Corresponding 

2007 Economic Census Data

NAICS Code

NAICS 

Industry 

Description

Maximum 

Number of 

Establishments

Maximum 

Number of 

Production 

Workers

Maximum Aggregate 

Production Hours 

Worked 

(thousands of hours)

Average 

Production 

Workers per 

Site 

Average 

Production 

Days per Year 

Per Worker 

(assuming 8 

hours/day)

Average 

Production 

Hours per 

Day Per 

Worker 

(assuming 250 

days/yr)

337122

Nonupholstered 

Household 

Furniture 

Manufacturing

3,428 49,764 95,685 15 240 7.69

337124

Metal Household 

Furniture 

Manufacturing

330 8,827 18,527 27 262 8.40

337127

Institutional 

Furniture 

Manufacturing

782 25,848 52,006 33 251 8.05

337129

Wood 

Television, 

Radio, 

Phonograph, and 

Sewing Machine 

Cabinet 

Manufacturing

270 1,541 3,094 6 251 8.03

337211

Wood Office 

Furniture 

Manufacturing

457 15,167 31,614 33 261 8.34

337212

Custom 

Architectural 

Woodwork and 

Millwork 

Manufacturing

2,228 32,184 64,362 14 250 8.00

337214

Office Furniture 

(except wood) 

Manufacturing

289 19,307 40,614 67 263 8.41
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Table 4-6 Continued

2007 Economic Census Data

Parameters Calculated from the Corresponding 

2007 Economic Census Data

NAICS Code

NAICS 

Industry 

Description

Maximum 

Number of 

Establishments

Maximum 

Number of 

Production 

Workers

Maximum Aggregate 

Production Hours 

Worked 

(thousands of hours)

Average 

Production 

Workers per 

Site 

Average 

Production 

Days per Year 

Per Worker 

(assuming 8 

hours/day)

Average 

Production 

Hours per 

Day Per 

Worker 

(assuming 250 

days/yr)

337215

Showcase, 

Partition, 

Shelving, and 

Locker 

Manufacturing

1,377 34,481 67,716 25 245 7.86

339950 Sign 

Manufacturing 6,383 52,755 103,305 8 245 7.83

336213 Motor Home 

Manufacturing 80 14,152 27,550 177 243 7.79

336214

Travel Trailer & 

Camper 

Manufacturing

862 39,282 75,327 46 240 7.67

Totals 33,737 617,680 1,211,952 18 245 7.85

Sources: 2007 U.S. Economic Census (Census 2007a) and EPA market profile (USEPA 2010a)
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4.2.3 Pre-Baseline Exposure Monitoring Data

The exposure monitoring data collected from IMIS for the period 2002 to 2009 on composite 

wood product fabrication are presented in this section.

Table 4-7 provides a summary of all IMIS 8-hour TWA, personal inhalation monitoring data for 

industry sectors within the composite wood product fabrication life cycle stage. Summary data 

for the individual sectors is provided in Appendix F. Appendix F also provides the maximum, 

median, and minimum values of the compiled formaldehyde monitoring data for worker activity

categories in each sector. As discussed in Section 4.2.1, sources of potential exposure in CWP 

fabrication sites include off-gassing of composite wood products and possibly other sources such 

as paints, adhesives and coatings, etc. However, the specific sources of exposure associated with 

the compiled IMIS data are unknown.

Table 4-7. Summary of All IMIS TWA Personal Monitoring Data for Industries Within 

the CWP Fabricator Life Cycle Stage

Statistic

Concentration 1

ppm mg/m

3

Maximum 1 1.229

Median 0.091 0.112

Minimum 0.00001 0.000012

Average 0.170 0.209

Number of Data Points 120

Source: OSHA 2009a

1 The formaldehyde concentration in mg/m3 was calculated from the provided 

concentration in ppm by multiplying the concentration in ppm by 1.229 mg/m3/ppm (see 

Appendix E).

4.2.4 Respiratory Protection Usage During Composite Wood Product Fabrication

Since OSHA IMIS data do not provide information on personal protective equipment use, OSHA

guidance on safe practices in the woodworking industry was reviewed to get an idea of OSHA’s 

recommendations for respiratory protection use during composite wood product fabrication. 

Inspection reports associated with the IMIS data were also examined to get an idea of the 

observed use of respiratory protection by workers when engaged in composite wood product 

fabrication activities. Appendix G contains a summary of each reviewed inspection report.

The OSHA Woodworking eTool (OSHA 2002a) offers guidance on safe practices in the

woodworking industry. The eTool requires provision of respirators and gloves to workers 

performing manual spray activities. Workers downstream of the spraying operation within the 

spray booth must be provided with an air-supplying respirator (OSHA 2002a). The prevalence 

of the practices required or recommended in the OSHA Woodworking eTool is unknown for the 

composite wood product fabrication industry.

The 120 TWA, personal monitoring data points discussed in Section 4.2.3 are associated with 61 

inspections. Of these 61 inspections, a total of 13 inspection reports for composite wood product 

fabrication facilities were obtained from OSHA and reviewed. These 13 inspection reports 

account for 39 of the 120 TWA, personal monitoring data points. Six other inspection reports 
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were requested but not reviewed either because they are no longer available due to their age or 

because they were not obtained in time to be considered for this assessment. As previously

discussed in Section 4.1.4, one of the 13 reviewed inspection reports (inspection number 

312479835; see Appendix G) was for a facility identified by NAICS code as a fabricator. 

However, the inspection report stated that the facility manufactures MDF and then fabricates 

flooring from the MDF. As the monitored workers were associated with the manufacture of 

MDF, this inspection report is discussed in Section 4.1.4 and Appendix G with the manufacturer 

inspection reports. Although this inspection report is associated with the 120 data points 

discussed in Section 4.2.3, it is not included in the discussion of this section below.

In addition to the 13 reviewed inspection reports, two inspection reports (inspection numbers 

303424014 and 304064835) were obtained and reviewed for inspections that occurred prior to 

2002 and hence are not associated with the 120 data points discussed above. Four other 

inspection reports for inspections dating prior to 2002 were requested but not reviewed either 

because they are no longer available due to their age or because they were not obtained in time to 

be considered for this assessment. Additionally, a single wholesale facility inspection report was 

requested, received, and reviewed (inspection number 306629171; see Appendix G). This 

inspection report is associated with the single wholesale facility IMIS data discussed in Section 

4.3.3. Although IMIS identifies the facility with a wholesaler NAICS code, worker activities 

described in the IMIS data and inspection report indicate the presence of fabrication activities. 

Therefore, this inspection report is discussed in this section and Appendix G with the CWP 

fabrication inspection reports. In conclusion, a total of 16 inspection reports were reviewed, and

15 of the reviewed inspection reports are discussed in this section.

In the 15 reviewed reports discussed in this section, all measured formaldehyde concentrations 

were below the OSHA PEL of 0.75 ppm for formaldehyde, with levels exceeding the action level 

(AL) of 0.5 ppm in only one facility (inspection number 306021239; see Appendix G). This 

single facility is a manufacturer of bath and kitchen wood cabinets and had three TWA 

measurements exceed the action level. Workers were not observed to be wearing respirators 

during the inspection at this site.

Five of the fifteen reports (33%) reviewed indicated the use of a respirator by workers as 

follows:

 One of the five reports identified the use of a half-face air purifying respirator in 

the mixing area where a formaldehyde-based glue is mixed and applied to wooden 

frame chairs via pneumatic guns.

 Two other reports identified the use of cartridge respirators during spray

application of formaldehyde-based coatings.

 Another report identified a facility that did not require respirator use in the spray

booths, although some workers were observed to be wearing organic vapor 

cartridge respirators during spraying activities.

 The fifth report was for the inspection of a facility in which the only identified 

inhalation PPE in use was the N95 disposal particulate respirator.
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An additional report indicated voluntary use of respirators but respirators were not worn during 

the inspection. The remaining nine inspection reports did not note the use or availability of 

respirators.

As in MDF manufacturing, respirator use by workers in composite wood product fabrication 

facilities has been noted when formaldehyde levels are below its AL. This may be a 

precautionary practice because spraying activities can increase the potential for exposure to

formaldehyde or it might result from the need to protect against chemicals and particulates other 

than formaldehyde. Only a single instance of the lack of respirator use has been noted 

(inspection number 306021239; see Appendix G) when exposure levels exceeded the AL (but 

were below the PEL).

The limited number of inspection reports that were available and examined show worker 

exposures to be below the formaldehyde PEL but do not provide enough information to conclude 

that respirators would necessarily be worn by workers when their exposure meets or exceeds the 

formaldehyde action level or PEL.

4.2.5 Baseline Exposure and the Effect of Analytical Options on Baseline Exposure for 

Composite Wood Product Fabrication

Monitoring data are a preferred approach for assessing exposure. However, as previously 

discussed in Section 3.2, the monitoring data are not adequate for assessing exposure at the 

baseline and for the analytical options. Therefore, this exposure assessment uses mathematical 

modeling to estimate indoor air concentration for the baseline and the analytical options. The 

mathematical modeling for indoor air concentration is presented in Section 3.3.1.1 and described 

in detail in Appendix E.

The model parameters include total emitting surface areas for the three CWPs in a CWP 

fabrication site, CWP formaldehyde off-gassing emission rates, total effective ventilation rate for 

a CWP fabrication site, and concentration of formaldehyde in the outside air. As discussed in

Section 3.3.1.1, due to data gaps in information on the values of these four parameters at 

representative CWP fabrication sites, a range of what-if values for indoor air concentration was 

calculated from bounding values for the ranges of three of the above four parameters. The whatif method for estimating indoor air concentration was applied to three limiting cases for the CWP 

type present in the CWP fabrication sites: only HWPW, or only PB, or only MDF. The 

calculation of concentration followed the algorithm outlined in Table 3-2. For each iteration of 

the algorithm, one parameter is varied between its minimum and maximum values while the 

other two varying parameters remain at their intermediate values. The fourth parameter, ambient 

air concentration of formaldehyde, is kept at a constant value. These steps were repeated for 

each CWP type. The what-if method used values for each parameter according to Table 3-4.

4.2.5.1 Results for Indoor Air Concentration Calculation Trials and Sensitivity 

Analysis

Results for the calculation trials for indoor air concentration that summarized in Table 3-2 are 

presented below. A sensitivity analysis based on these results was conducted and is discussed 

below. Results are presented in Table 4-8 for each of the three calculation trials for the baseline 
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low-end air concentration for each of the three limiting cases for CWP type and similarly for the 

high-end indoor air concentration. This table also contains the results of the calculation of a 

baseline intermediate indoor air concentration for each of the three CWP types. Similar results 

are presented in Table 4-9 through Table 4-11 for the CARB ATCM Phase 1, the FSCWPA / 

CARB ATCM Phase 2, and the NAF analytical options.

The results in Table 4-8 through Table 4-11 demonstrate the sensitivity of the calculated indoor 

air concentration to variation in the value of each model parameter. The purpose of observing 

the sensitivity of the mass balance equation is to understand the impact of the estimated range of 

values for each parameter of the equation on the calculated concentration. As the value of one 

parameter is varied while the other parameters are kept constant, the changes in the calculated 

concentration resulting from the variation of a single parameter can be compared to the changes 

in concentration resulting from the variation of other parameters. For example, the row labeled 

“Vary Emitting Surface Area” shows the changes in indoor air concentration from varying the 

emitting surface area from its minimum to its maximum values while keeping effective 

ventilation rate and emission rate constant at their intermediate values. This trend is shown for 

each CWP type. The results indicate that, for each CWP type, the indoor air concentration is 

least sensitive to emission rate. The row “Vary Emission Rate” shows the smallest relative 

changes in indoor air concentration from low-end to high-end value (relative change is defined as 

the difference between the high-end and low-end values divided by the low-end value). Note 

that for each “vary scenario” the MDF scenario estimates higher exposures than the HWPW and 

PB scenarios due to the higher emission rates of MDF.

The rows “Vary Emitting Surface Area” and “Vary Effective Ventilation Rate” show relative 

changes in indoor air concentration of a similar order of magnitude. At baseline, the relative 

changes in indoor air concentration due to varying emitting surface area and effective ventilation 

rate are approximately two to nine times higher than the relative changes due to varying emission 

rate. The relative changes in indoor air concentration due to varying emitting surface area are 

higher than the relative changes due to varying effective ventilation rate. This effect is due to the 

wide range of values of emitting surface area chosen (10% and 1,000% of the intermediate 

value). This is especially notable given that mathematically the mass balance equation would 

show greater sensitivity to the effective ventilation rate in general since indoor air concentration

is inversely proportional to the effective ventilation rate. Therefore, particularly at lower values 

of effective ventilation rate, the indoor air concentration will change more rapidly as effective 

ventilation rate is changed. On the other hand, indoor air concentration is directly proportional 

to emitting surface area and emission rate. Therefore, indoor air concentration changes linearly

with both emitting surface area and emission rate.

4.2.5.2 Estimation of a Range of Values for the What-If Low-End and the WhatIf High-End Indoor Air Concentrations that Account for All CWP Types

As summarized in Table 3-2, the what-if low-end and high-end indoor air concentrations for 

each CWP type were estimated by choosing the minimum and maximum, respectively, of the 

results of the three calculation trials made for each of these two concentration values. As

discussed in Section 3.3.1.1, the concentration values that were chosen as the estimate of the 

what-if low-end indoor air concentration for each CWP type were combined into a single range 

of what-if low-end indoor air concentrations that encompasses all three estimates to account for
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the possibility that a mixture of the three CWP types is used in a CWP fabrication site. This was 

also done for the chosen high-end indoor air concentration for each CWP type. These ranges for 

the values of the what-if low-end indoor air concentration and what-if high-end indoor air 

concentration are given Table 4-12 in for the baseline and the analytical options.

4.2.5.3 Final Results for the Estimation of What-If Indoor Air Concentrations

The estimated ranges for low- and high-end what-if indoor air concentration given in Table 4-12

were combined into an overall range for the baseline and each of the analytical options. The 

overall range is defined as the range bound by the low-end concentration from the low-end range 

and the high-end concentration from the high-end range. These overall ranges are presented in

Table 4-13. The best estimate concentration values summarized in Table 4-13 are calculated as 

the midpoint of the overall range of estimated concentration values for the baseline and each 

analytical option. The midpoint of the overall range of estimated concentrations is chosen to 

represent the best estimate due to the varying uncertainties of the model parameter values, which 

are discussed in Section 3.3.1.1. Table 4-13 also provides the percentage reductions in indoor air 

concentration from the baseline value for the analytical options.

The rationale for this best estimate comes from considering pre-baseline IMIS data for 

fabrication and uncertainties in model parameters. Modeling results obtained using pre-baseline 

emission levels were compared to the pre-baseline IMIS data for fabrication. This comparison is 

presented in Figure 4-1 and shows that the midpoint of the lowest and highest model results (the 

midpoint of the overall range of model results) compares well to the median value of the IMIS

data. The pre-baseline emission levels used in the calculations are given in Appendix D and the 

corresponding modeling results are given in Appendix I. However, comparing IMIS data, which 

are aggregate exposures that may have one or more sources of formaldehyde of which CWPs 

may or may not be included, to model results for off-gassing alone, is highly uncertain. 

Likewise, the representativeness of the model parameter values are of varying uncertainty, as 

discussed in Section 3.3.1.1. Therefore, it is most logical to select the midpoint of the lowest and 

highest model results as the best estimate of formaldehyde concentration.
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Figure 4-1. Comparison of Model Results for Ranges of What-If Indoor Air Concentrations 

using Pre-Baseline Emission Rates with OSHA IMIS Data

The range of what-if indoor air concentrations given in Table 4-13 is the estimate of the range of 

values for the average concentration of airborne formaldehyde in a CWP fabrication site that is 

due to off-gassing from HWPW, PB, and MDF. As presented in Section 3.3.1.1 and described in 

detail in Appendix E, these concentration values were estimated based on a steady-state mass 

balance that equates the formaldehyde generation rate due to off-gassing from HWPW, PB, and 

MDF present at a CWP fabrication site to the rate at which airborne formaldehyde is exhausted 

from the CWP fabrication site through ventilation with outdoor air. In this model, which is 

discussed in detail in Section 3.3.1.1, the off-gassing emissions from all of the exposed CWP 

surfaces are diluted with outside air, which contains the ambient concentration of formaldehyde,

and the fabrication site is assumed to be a well-mixed box resulting in a uniform indoor air 

concentration throughout the site. The assumption of a well-mixed box model is based on the 

assumption that the CWP as well as the ventilation sources are for the most part uniformly 

distributed in a CWP fabrication site.

As discussed in Section 3.3.1.1, due to data gaps in information on the values of the four model 

parameters at representative CWP fabrication sites, a range of what-if values for indoor air 

concentration was calculated from bounding values for the ranges of three of the four 

parameters. The estimated range for average indoor air concentration at a CWP fabrication site 

is characterized as a range of what-if results because each concentration value in this range 

corresponds to combinations of choices, or what-if values, for the model parameters. Although 

the prevalence of the model parameter what-if values at actual CWP fabrication sites is 

unknown, the ranges of the model parameter values should be realistic such that any given 

choice, or what-if value, for any model parameter represents a possible value at actual CWP 

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40

Pre-B

aseline IMIS

D

ata

a

n

d

Pre-B

aseline

M

o

delin

g

Results

Concentration (ppm)

IMIS Data

Overall Range of Model Results

High-End Range of Model Results

Intermediate Range of Model Results

Low-End Range of Model Results
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fabrication sites. However, as discussed in Section 3.3.1.1, the ranges of the model parameters 

were estimated with varying levels of accuracy. It was not possible to validate the modeling 

results for indoor air concentration as further discussed in Section 5.1.1.

4.2.5.4 The Assessment of Exposure Level for the Baseline and the Analytical

Options

The duration of exposure was assessed to be eight hours per day as presented in Section 4.2.2; 

therefore, the estimated what-if steady-state average indoor air concentrations in a CWP 

fabrication site presented in Table 4-13 are assessed as the 8-hour TWA exposure concentration. 

As discussed in Section 4.2.4, there is insufficient information to determine whether respiratory

PPE is utilized by workers and therefore the estimated what-if indoor air concentration was 

assessed as the exposure concentration.

This exposure concentration is due only to off-gassing from the CWP products. As discussed in

Section 4.2.1, there is some indication of potential sources of formaldehyde inhalation exposure 

in a CWP fabrication site other than off-gassing of formaldehyde from the three CWPs (such as 

adhesives and the application of overlays). The relative significance of the contribution of these 

other potential sources to aggregate exposure is unknown. Different approaches were considered 

for their assessment but they were not assessed due to data gaps.

Average daily concentration (ADC) and lifetime average daily concentration (LADC) were 

calculated for each indoor air concentration value reported in Table 4-13. As described in

Appendix E, ADC and LADC were calculated assuming exposure duration of 8 hours per day

and exposure frequency of 250 days per year over 40 working years per lifetime for ADC and 

over a lifetime of 70 years for LADC. The ADC and LADC results are presented in Table 4-14

and Table 4-15.

Results in Table 4-13 show that the maximum formaldehyde exposure concentration decreases as 

lower (more stringent) emission standards are implemented. However, the CARB ATCM Phase 

1 limits result in little or no reduction in exposure from the baseline year. This effect is because 

many composite wood products are expected to be already meeting more stringent standards by 

2013. Note the minimum exposure concentrations remain constant throughout the different 

analytical option periods. This effect is because a small portion of the market is expected to be 

already meeting the NAF standards by the baseline period. The emission levels of NAFcompliant composite wood products are assumed to remain unchanged and no effect of 

analytical options is expected for these products.
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Table 4-8. Results for the Calculation Trials for the What-If Low- and High-End Baseline Indoor Air Concentrations

Varied Parameter

Calculated Concentration for Baseline, ppm

Intermediate 4 Low End 5 High End 6

HWPW PB MDF HWPW PB MDF HWPW PB MDF

Vary Emitting Surface Area 1

0.0095 0.0110 0.0181

0.0055 0.0057 0.0064 0.0488 0.0637 0.1345

Vary Effective Ventilation 

Rate 2 0.0058 0.0060 0.0071 0.1362 0.1809 0.3934

Vary Emission Rate 30.0064 0.0064 0.0092 0.0218 0.0445 0.0902

1

For area, the intermediate value is based on the aggregate average per-site throughput calculated using domestic composite wood product consumption data from the 

EPA market profile. The high-end and low-end values are calculated assuming 1,000% and 10% of the aggregate average throughput, respectively.

2 Effective ventilation is varied based on values shown in Table 3-3. The low-end, typical, and high-end values are 50, 1,500 and 10,000 cfm, respectively.

3 Emission rate is varied based on values shown in Table 3-4.

4

Intermediate concentration is calculated using intermediate value for surface area, typical value for effective ventilation rate, and weighted-average baseline 

emission rate for each CWP type.

5 Low-end values calculated according to Table 3-2.

6 High-end values calculated according to Table 3-2.
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Table 4-9. Results for the Calculation Trials for the What-If Low- and High-End CARB Phase 1 Indoor Air Concentrations

Varied Parameter

Calculated Concentration for Phase 1, ppm, and % Change from Corresponding Baseline Value

Intermediate 4 Low End 5 High End 6

HWPW PB MDF HWPW PB MDF HWPW PB MDF

Vary Emitting Surface Area 1

0.0077

(-18.8%)

0.011

(-3.0%)

0.0176

(-2.7%)

0.0054

(-3.2%)

0.0057

(-0.6%)

0.0064

(-0.8%)

0.0309

(-36.6%)

0.0604

(-5.2%)

0.1296

(-3.6%)

Vary Effective Ventilation 

Rate 2

0.0055

(-4.6%)

0.0059

(-0.8%)

0.0070

(-1.0%)

0.0826

(-39.3%)

0.1710

(-5.5%)

0.3787

(-3.7%)

Vary Emission Rate 3 0.0064

(0%)

0.0064

(0%)

0.0092

(0%)

0.0111

(-49.3%)

0.0143

(-67.8%)

0.0288

(-68.0%)

1

For area, the intermediate value is based on the aggregate average per-site throughput calculated using domestic composite wood product consumption data from the 

EPA market profile. The high-end and low-end values are calculated assuming 1,000% and 10% of the aggregate average throughput, respectively.

2 Effective ventilation is varied based on values shown in Table 3-3. The low-end, typical, and high-end values are 50, 1,500 and 10,000 cfm, respectively.

3 Emission rate is varied based on values shown in Table 3-4.

4

Intermediate concentration is calculated using intermediate value for surface area, typical value for effective ventilation rate, and weighted-average Phase 1

emission rate for each CWP type.

5 Low-end values calculated according to Table 3-2.

6 High-end values calculated according to Table 3-2.
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Table 4-10. Results for the Calculation Trials for the What-If Low- and High-End FSCWPA / CARB Phase 2 Indoor Air 

Concentrations

Varied Parameter

Calculated Concentration for FSCWPA / Phase 2, ppm, and % Change from Corresponding Baseline Value

Intermediate 4 Low End 5 High End 6

HWPW PB MDF HWPW PB MDF HWPW PB MDF

Vary Emitting Surface Area 1

0.0072

(-23.5%)

0.011

(-3.9%)

0.0175

(-3.2%)

0.0053

(-4.0%)

0.0057

(-0.7%)

0.0063

(-0.9%)

0.0265

(-45.7%)

0.0595

(-6.7%)

0.1288

(-4.2%)

Vary Effective Ventilation 

Rate 2

0.0054

(-5.8%)

0.0059

(-1.1%)

0.0070

(-1.2%)

0.0693

(-49.1%)

0.1681

(-7.1%)

0.3763

(-4.3%)

Vary Emission Rate 3 0.0064

(0%)

0.0064

(0%)

0.0092

(0%)

0.0084

(-61.5%)

0.0110

(-75.4%)

0.0190

(-78.9%)

1

For area, the intermediate value is based on the aggregate average per-site throughput calculated using domestic composite wood product consumption data from the 

EPA market profile. The high-end and low-end values are calculated assuming 1,000% and 10% of the aggregate average throughput, respectively.

2 Effective ventilation is varied based on values shown in Table 3-3. The low-end, typical, and high-end values are 50, 1,500 and 10,000 cfm, respectively.

3 Emission rate is varied based on values shown in Table 3-4.

4

Intermediate concentration is calculated using intermediate value for surface area, typical value for effective ventilation rate, and weighted-average Phase 2

emission rate for each CWP type.

5 Low-end values calculated according to Table 3-2.

6 High-end values calculated according to Table 3-2.
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Table 4-11. Results for the Calculation Trials for the What-If Low- and High-End NAF Indoor Air Concentrations

Varied Parameter

Calculated Concentration for Phase NAF, ppm, and % Change from Corresponding Baseline Value

Intermediate 4 Low End 5 High End 6

HWPW PB MDF HWPW PB MDF HWPW PB MDF

Vary Emitting Surface Area 1

0.0064

(-32.0%)

0.0064

(-41.3%)

0.0110

(-39.3%)

0.0052

(-5.5%)

0.0052

(-8.0%)

0.0057

(-11.1%)

0.0184

(-62.2%)

0.0184

(-71.1%)

0.0637

(-52.7%)

Vary Effective Ventilation Rate 2 0.0053

(-7.9%)

0.0053

(-11.3%)

0.0060

(-15.1%)

0.0451

(-66.9%)

0.0451

(-75.1%)

0.1807

(-54.1%)

Vary Emission Rate 3 0.0064

(0%)

0.0064

(0%)

0.0092

(0%)

0.0064

(-70.5%)

0.0064

(-85.5%)

0.0110

(-87.8%)

1

For area, the intermediate value is based on the aggregate average per-site throughput calculated using domestic composite wood product consumption data from 

the EPA market profile. The high-end and low-end values are calculated assuming 1,000% and 10% of the aggregate average throughput, respectively.

2 Effective ventilation is varied based on values shown in Table 3-3. The low-end, typical, and high-end values are 50, 1,500 and 10,000 cfm, respectively.

3 Emission rate is varied based on values shown in Table 3-4.

4

Intermediate concentration is calculated using intermediate value for surface area, typical value for effective ventilation rate, and weighted-average NAF

emission rate for each CWP type.

5 Low-end values calculated according to Table 3-2.

6 High-end values calculated according to Table 3-2.

Table 4-12. Estimated Low-End, Intermediate, and High-End Ranges of Values for the Site-Average Indoor Air Concentration at the

Baseline and for the Analytical Options

Case Intermediate (ppm) Low End (ppm) High End (ppm)

Baseline 0.0095 – 0.0181 0.0055 – 0.0092 0.0218 – 0.3934

Phase 1 0.0077 (-18.8%) – 0.0176 (-2.7%) 0.0054 (-3.2%) – 0.0092 (0%) 0.0111 (-49.3%) – 0.3787 (-3.7%)

FSCWPA / Phase 2 0.0072 (-23.5%) – 0.0175 (-3.2%) 0.0053 (-4.0%) – 0.0092 (0%) 0.0084 (-61.5%) – 0.3763 (-4.3%)

NAF 0.0064 (-32.0%) – 0.0110 (-39.3%) 0.0052 (-5.5%) – 0.0092 (0%) 0.0064 (-70.5%) – 0.1807 (-54.1%)
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Table 4-13. Estimated Overall Range and Best Estimate Site-Average Indoor Air Concentration at the Baseline and for the Analytical

Options

Case

Overall Range 

(ppm)

Best Estimate

Concentration1

(ppm)

Reduction 

from

Baseline (%)

Baseline 0.0055 – 0.3934 0.1995 --

Phase 1 0.0054 – 0.3787 0.1920 -3.7

FSCWPA / Phase 2 0.0053 – 0.3763 0.1908 -4.3

NAF 0.0052 – 0.1807 0.0930 -53.4

1 The best estimate concentration is the midpoint of the overall range. The 

overall range is defined as the low-end value from the low-end range and the 

high-end value from the high-end range. The reduction from baseline, ADC, 

and LADC values are calculated from the best estimate concentration value.

Table 4-14. Overall Range and Best Estimate ADC at the Baseline and for the Analytical Options

Case Overall Range (μg/m3)

Best Estimate ADC

(μg/m3)

Baseline 1.556 – 110.4 56.0

Phase 1 1.506 – 106.3 53.9

FSCWPA / Phase 2 1.494 – 105.6 53.5

NAF 1.471 – 50.71 26.1

Table 4-15. Overall Range and Best Estimate LADC at the Baseline and for the Analytical Options

Case Intermediate (μg/m3)

Best Estimate LADC

(μg/m3)

Baseline 0.8894 – 63.08 32.0

Phase 1 0.8607 – 60.72 30.8

FSCWPA / Phase 2 0.8536 – 60.34 30.6

NAF 0.8407 – 28.98 14.9
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4.2.6 Dermal Exposures during Composite Wood Product Fabrication

Dermal exposures to CWPs are not quantifiable using the EPA dermal exposure models for 

liquids and solids (these models are only applicable to dermal exposure to uncured resin, which 

may occur upstream of the press in the CWP manufacturing process).

4.3 Exposure Assessment for Wholesale

This section presents and discusses the assessment of formaldehyde exposures from the 

wholesale of composite wood products.

4.3.1 Description of Life Cycle Stage

Wholesalers buy products from manufacturers in bulk for the purpose of resale to various 

industries and individuals. Wholesale products may include composite wood products and CWP 

fabrication products (downstream products). A single wholesaler may sell many different types 

of composite wood products. The U.S. Census Bureau defines wholesale facilities as those who 

“sell or arrange the purchase or sale of capital or durable goods to other businesses” (Census 

2007a). However, IMIS data, which are presented in Section 4.3.3, indicate that some wholesale 

facilities may also process composite wood products on site (the reported worker activities at 

wholesale facilities include “sawing”).

4.3.2 Use Volumes and Number of Establishments, Employees, Employed Hours, and Work 

Days

Information related to the number of sites, number of employees, and facility-specific use rates 

(including storage and wholesale) of composite wood products and CWP fabrication articles 

made of composite wood products were researched. Data for the number of sites and employees 

from the 2007 U.S. Economic Census are provided in the EPA market profile (USEPA 2010a). 

However, actual loading data of the total emitting surface area of composite wood products at 

wholesale settings were not found. Table 4-16 summarizes the census data identified for 

wholesale facilities that may sell composite wood products or articles fabricated from composite 

wood products as obtained from the EPA market profile. It is uncertain whether all facilities in 

the identified NAICS codes sell composite wood products or downstream articles made of 

composite wood products. Therefore, the number of sites and employees identified in Table 

4-16 may represent wholesalers that do not use composite wood products and are considered 

maximum values.
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Table 4-16. Summary of 2007 Economic Census Data for Wholesale Facilities

NAICS 

Code NAICS Industry Description

Maximum 

Number of 

Establishments

Maximum 

Number of 

Paid 

Employees

423210 Furniture merchant wholesalers 6,640 69,103

423220 Home furnishing merchant wholesalers 7,540 93,060

423310 Lumber, plywood, millwork, and wood panel merchant wholesalers 8,428 138,739

423320 Brick, stone, and related construction material merchant wholesale 3,383 35,005

423330 Roofing, siding, and insulation material merchant wholesalers 2,587 32,662

423390 Other construction material merchant wholesalers 3,383 37,920

423440 Other commercial equipment merchant wholesalers 4,352 48,976

423450 Medical equipment merchant wholesalers 8,282 141,282

423490 Other professional equipment and supplies merchant wholesalers 2,297 D

10

423510 Metal service centers and other metal merchant wholesalers 10,148 144,954

423610 Elec. equip. and wiring merchant wholesalers 13,277 169,355

423620 Electric appliance merchant wholesalers 3,110 44,819

423710 Hardware merchant wholesalers 6,828 83,542

423720 Plumbing equip. merchant wholesalers 6,939 86,092

423730 HVAC equip. merchant wholesalers 5,071 50,495

423740 Refrigeration equipment and supplies merchant wholesalers 1,265 11,024

423830 Industrial machinery and equipment merchant wholesalers 29,838 319,557

423850 Service establishment equipment and supplies merchant wholesalers 4,576 D

10

423910 Sporting and recreational goods and supplies merchant wholesalers 6,192 55,842

424610 Plastics materials and basic forms and shapes merchant wholesaler 3,248 32,552

424950 Paint, varnish, and supplies merchant wholesalers 1,649 14,631

Source: EPA market profile (USEPA 2010a)

4.3.3 Pre-Baseline Exposure Monitoring Data

Formaldehyde monitoring data for various worker activities at various wholesale settings were 

obtained from the OSHA IMIS database (OSHA 2009a). Only two data points from a single 

wholesale site classified under one of the NAICS codes identified in Table 2-1 were available for 

the pre-baseline period (2002 to 2009). Table 4-17 presents these data by worker activity.

 

10 "D" is used to indicate that the data have been withheld to avoid disclosure.
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Table 4-17. Summary of Formaldehyde Inhalation Monitoring Data for Wholesalers from 

the OSHA IMIS Database

Industry

Worker 

Activity 

Description

Number of 

Sites 

Monitored

Monitored 

Formaldehyde 

Concentration 

(ppm)

Monitored 

Formaldehyde 

Concentration 

(μg/m3)

1

Monitoring 

Type Year

Furniture 

Merchant 

Wholesalers

Band Saw

Operator

1

0.002 2.46 Personal 2003

Not Detected Not Detected Personal 2003

Panel Saw

Operator 0.002 2.46 Personal 2003

CNC 

Operator Not Valid2 Not Valid Personal 2003

1 The formaldehyde concentration in μg/m3 was calculated from the provided concentration in ppm by

multiplying the concentration in ppm by 1,229 μg/m3/ppm (see Appendix E).

2 Data point reported as “not valid” in the IMIS database; likely an invalid measurement. 

4.3.4 Baseline Exposure and the Effect of Analytical Options on Baseline Exposure for 

Wholesale

Exposures in wholesale settings are not assessed quantitatively due to data gaps. There is a lack 

of information on the ventilation rate at wholesale settings to allow for a what-if analysis similar 

to what was completed for the fabrication life cycle stage. Therefore, it is not possible to 

accurately quantify the exposure concentrations during the baseline period and the reduction of 

exposure concentrations resulting from the analytical options.

The formaldehyde concentration resulting from off-gassing is expected to decrease with the 

implementation of more stringent regulations. However, as discussed previously, the 

implementation of CARB ATCM Phase 1 limits is expected to result in little or no reduction in 

exposure from the baseline year. This is because most composite wood products in the market 

would already be meeting more stringent limits by 2013.

4.3.5 Dermal Exposures during Wholesale

Dermal exposures to CWPs are not quantifiable using the EPA dermal exposure models for 

liquids and solids.

4.4 Exposure Assessment for Retail

This section presents and discusses the assessment of formaldehyde exposures from retail due to 

composite wood products.

4.4.1 Description of Life Cycle Stage

Retailers operate from fixed locations and sell products for direct consumption by the purchaser 

(individuals or businesses). These retailers may receive HWPW, MDF, or PB directly as 
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products or included in articles fabricated using composite wood products. Like wholesale 

sectors, retail sectors are not distinguished by composite wood product type (Census 2007a).

4.4.2 Use Volumes and Number of Establishments, Employees, Employed Hours, and Work 

Days

Information related to the number of sites, number of employees, and facility-specific use rates 

(including storage and retail) of composite wood products and CWP fabrication products were 

researched. The number of sites and employees data from the 2007 U.S. Economic Census 

(Census 2007a) was identified. However, actual loading data of the total emitting surface area of 

composite wood products at wholesale settings were not found. Table 4-18 summarizes the 

census data identified for retail facilities that may sell composite wood products or articles 

fabricated from composite wood products. It is uncertain whether all facilities in the identified 

NAICS codes sell composite wood products or downstream articles made of composite wood 

products. Therefore, the number of sites and employees identified in Table 4-18 may represent 

retailers that do not use composite wood products and are considered maximum values.

The duration and frequency of exposure were assumed to be 8 hours per day and 250 days per 

year, respectively. This is supported to some extent by IMIS data on duration. Some exposure 

data points in IMIS do not include an exposure duration and other data points include an 

exposure duration of “daily” or other frequency without comment on the number of hours of 

exposure per day. For retail, 17 exposure data points (sampled in 2002 through 2009) were 

collected. For these 17 data points, the following exposure duration data were included in 

IMIS:

11

 Exposure durations of blank or “daily”: seven data points (41%);

 Exposure durations of eight hours per day: three data points (18%);

 Exposure duration of three hours per week: one data point (6%); 

 Exposure duration of 40 hours per week: three data points (18%); and

 Exposure duration of “monthly”, “routinely”, or “varies”: three data points (18%).

 

11 Note: percentages should add to 100 percent but may not due to rounding.
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Table 4-18. Summary of 2007 Economic Census Data for Retail Facilities

NAICS 

Code NAICS Industry Description

Maximum 

Number

of Establishments

Maximum 

Number 

of Paid Employees

441210 Recreational vehicle dealers 3,100 42,669

442110 Furniture stores 28,834 266,374

442210 Floor covering stores 14,534 89,420

442291 Window treatment stores 2,652 9,626

442299 All other home furnishings stores 19,124 192,057

443111 Household appliance stores 9,336 70,045

443112 Radio, television, and other electronics stores 29,051 309,374

443120 Computer and software stores 10,428 92,777

444110 Home centers 6,953 579,442

444120 Paint and wallpaper stores 7,860 35,491

444130 Hardware stores 16,454 143,738

444190 Other building material dealers 39,551 405,755

444210 Outdoor power equipment stores 4,357 25,882

444220 Nursery, garden center, and farm supply stores 15,895 141,014

445110 Supermarkets and other grocery (except convenience) 

stores 64,881 2,432,425

448110 Men's clothing stores 8,321 57,340

448120 Women's clothing stores 36,220 339,798

448130 Children's and infants' clothing stores 7,102 98,729

448140 Family clothing stores 28,254 642,117

448150 Clothing accessories stores 7,494 37,575

448190 Other clothing stores 12,034 97,581

451120 Hobby, toy, and game stores 9,357 135,688

451130 Sewing, needlework, and piece goods stores 5,663 49,450

452111 Department stores (except discount department stores) 3,533 534,189

452112 Discount department stores 5,001 690,265

452910 Warehouse clubs and supercenters 4,260 1,244,237

452990 All other general merchandise stores 33,061 294,783

453110 Florists 19,822 93,967

453210 Office supplies and stationery stores 9,558 112,734

453220 Gift, novelty, and souvenir stores 31,391 193,317

453920 Art dealers 6,677 23,126

453930 Manufactured (mobile) home dealers 3,878 21,068

453998 All other miscellaneous store retailers (except tobacco 

stores) 17,270 88,296

454113 Mail-order houses 7,324 220,516

454390 Other direct selling establishments 22,077 131,013

Source: EPA market profile (USEPA 2010a)

4.4.3 Pre-Baseline Exposure Monitoring Data

Formaldehyde exposure monitoring data for various worker activities at various retail settings

obtained from the OSHA IMIS database (OSHA 2009a) for the period of 2002 to 2009 are 

presented in Table 4-19. Pre-baseline data are available for seven retail sectors only, and for 

most only a single monitoring data point is available. A total of 17 data points are available for 

the entire sector during the pre-baseline period.
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Table 4-19. Summary of Formaldehyde Inhalation Monitoring Data for Retailers from the OSHA IMIS Database

Industry

Worker Activity 

Description

Number of Sites 

Monitored

Number of Data 

points

Monitored 

Formaldehyde 

Concentration 

(ppm)

Monitored 

Formaldehyde 

Concentration 

(μg/m3)

1

Monitoring 

Type Year

Recreational Vehicle 

Dealers Sawing 1 1 0.002 2.46 Personal 2006

Furniture Stores

Cabinet Maker 1 1 0.069 84.8 Personal 2002

Front Right of Store

1 5

Not Detected 2 Not Detected 2 Area 2008

Front Left of Store Not Detected 2 Not Detected 2 Area 2008

Back Left of Store Not Detected 2 Not Detected 2 Area 2008

Back Right of Store Not Detected 2 Not Detected 2 Area 2008

Middle of Store Not Detected 2 Not Detected 2 Area 2008

All Other Home 

Furnishing Stores Sale 1 1 0.017 20.9 Area 2006

Radio, Television & 

Other Electronic Stores Warehouse Handler 1 1 0.14 172.1 Personal 2004

Home Centers Cabinet Maker/Painter 1 1 0.00001 20.012 2Personal 2007

Other Building Material 

Dealers

Laminator 1 1 0.055 67.6 Personal 2003

Painting 11 0.1 122.9 Personal 2008

Operator 1 0.19 233.5 Personal 2008

Driver 1 1 Not Detected 2 Not Detected 2 Area 2004

Sales Rep 1 1 Not Detected 2 Not Detected 2 Area 2002

Department Stores 

(except Discount 

Department Stores)

Merchandise 

Coordinator 1 1 Not Detected 2 Not Detected 2 Area 2003

Unpack Clothing 1 1 Not Detected 2 Not Detected 2 Area 2006

1 The formaldehyde concentration in μg/m3 was calculated from the provided concentration in ppm by multiplying the concentration in ppm by 1,229 

μg/m3/ppm (see Appendix E).

2 The minimum reliable quantitation limit (RQL) identified for OSHA sampling and analysis methods is 0.00058 ppm. Non-detected values and 

values below this RQL are set equal to the RQL for the exposure calculations.
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4.4.4 Baseline Exposure and the Effect of Analytical Options on Baseline Exposure for 

Retail

Exposures in retail settings are not assessed quantitatively due to data gaps. There is a lack of 

information on the ventilation rate at retail settings to allow for a what-if analysis similar to what 

was completed for the fabrication life cycle stage. Therefore, it is not possible to accurately 

quantify the exposure concentrations during the baseline period and the reduction of exposure 

concentrations resulting from the analytical options.

The formaldehyde concentration resulting from off-gassing is expected to decrease with the 

implementation of more stringent regulations. However, as discussed previously, the 

implementation of CARB ATCM Phase 1 limits is expected to result in little or no reduction in 

exposure from the baseline year. This is because most composite wood products in the market 

would already be meeting more stringent limits by 2013.

Although the U.S. Census Bureau defines the retail trade sector as “establishments engaged in 

retailing merchandise, generally without transformation, and rendering services incidental to the 

sale of merchandise,” the limited IMIS data indicate that sawing, assembling, building, painting, 

and other laboring activities are performed at some retail facilities. A further search of one 

facility reported in the IMIS suggests that some fabrication sites could be involved in direct 

retail. For example, one company makes custom cabinets and sells these cabinets to builders, 

dealers, and consumers. This company is classified under NAICS 444190: “Other Building 

Material Dealers.” The exposures at fabrication sites have been assessed in Section 4.2.

4.4.5 Dermal Exposures during Retail

Dermal exposures to CWPs are not quantifiable using the EPA dermal exposure models for 

liquids and solids.

4.5 Exposure Assessment for Office Workers during Commercial Use

This section presents and discusses the assessment of formaldehyde exposures resulting from the 

occupancy of office buildings (commercial buildings) containing composite wood products by 

office workers.

4.5.1 Description of Life Cycle Stage

The commercial use of composite wood products includes the occupancy by office workers of 

office buildings (commercial buildings) containing composite wood products. These office 

workers may be exposed to airborne formaldehyde emitted from CWPs or CWP fabrication 

products that are present in the commercial building.

4.5.2 Use Volumes and Number of Establishments, Employees, Employed Hours, and Work 

Days

Data that provide inventories of each composite wood product within commercial office 

buildings were not found. Additionally, census data that provide the number of commercial use 

sites, the total number of employees, and employee hours worked per day and days worked per 
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year in office settings were not found. These data are difficult to obtain as commercial use 

settings, such as office buildings, occur across multiple industries. For example, the industries 

described in the upstream life cycle stages in this report (manufacturing, wholesale, retail) all 

may involve office settings in addition to the settings described in their respective sections 

above.

4.5.3 Pre-Baseline Exposure Monitoring Data

This section provides pre-baseline indoor air concentration monitoring data obtained from the 

BASE study from 1994 to 1998. These data are presented to compare to the model results 

presented in the next subsection. Table 4-20 presents some general characteristics of the 100 

commercial and public office buildings collected from the BASE study, including the 

construction date, floor area, number of floors and occupants.

Table 4-20. Overview of General Characteristics of the 100 BASE Buildings

Characteristic (unit) Range Average Median

Construction Date (year) 1850 - 1996 1961 1972

Gross Floor Area (m2) 1,665 - 134,195 24,756 13,964

Occupied Floor Area (m2) 629 - 98,474 16,380 8,477

Number of Floors Above Grade 1 – 53 9 5

Number of Building

Occupants (including visitors) 87 – 6,500 1,020 705

Source: BASE 1998a

Formaldehyde was detected in a quantifiable amount in all 100 buildings. Table 4-21 presents a 

summary of the monitored formaldehyde concentrations in office buildings that were obtained 

from the BASE study (BASE 1998a). The study only presented the overall formaldehyde 

concentrations within the buildings and did not distinguish exposures according to worker 

activities. Table 4-21 also provides the summary statistics of the monitored outdoor 

formaldehyde concentrations from the BASE study, which were measurements made outside of 

the office buildings.

Table 4-21. Summary of Formaldehyde Inhalation Monitoring Data for Office 

Occupational Settings and Outdoor Measured Concentrations from the BASE Study

Percentile

Formaldehyde Concentration (μg/m3) Formaldehyde Concentration (ppm)

Indoors Outdoors Indoors Outdoors

100th (Maximum) 51 13 0.041 0.011

95th 32 10 0.026 0.008

75th 21 5.7 0.017 0.005

50th (Median) 15 3.0 0.012 0.002

25th 9.2 1.4 0.007 0.001

5

th 4.4 0.40 0.004 0.000

Arithmetic Mean 16 3.9 0.013 0.003

Source: BASE 1998a
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4.5.4 Baseline Exposure and the Effect of Analytical Options on Baseline Exposure for 

Office Buildings

What-if values for indoor air concentrations in an office building related to baseline and the 

analytical options were estimated using mathematical modeling. The mathematical modeling for 

indoor air concentration is presented in Section 3.3.1.2 and described in detail in Appendix E.

The estimation results are given in Table 4-22. The results in Table 4-22 are for the three 

limiting cases of the office workstation being fabricated from 100% HWPW, 100% PB, and 

100% MDF. These results were combined into a single range, which is given in Table 4-23.

The range of what-if indoor air concentrations given in Table 4-23 is the estimate of the range of 

values for the steady-state indoor air formaldehyde concentration in a work space resulting from 

the off-gassing emissions from new HWPW, PB, and MDF components of the workstation

occupying the work space and due to the ventilation with outside air containing ambient 

formaldehyde. The emitting surface area of each workstation component and the ventilation rate 

of the work space containing the workstation are values given in BIFMA M7.1-2007 –

“Standard Test Method for Determining VOC Emissions from Office Furniture Systems, 

Components and Seating”.

In homes, the most significant sources of formaldehyde are likely to be CWPs made from UF 

resins (USEPA 2011b). The literature search did not identify information to indicate that sources 

of formaldehyde in office buildings are significantly different than in homes. Therefore, it is 

assumed that CWPs are the most significant source of formaldehyde in office buildings.

Office building ventilation systems likely contain a recirculation component, which results in the 

mixing of air from various sections of the office building with outside air and the subsequent 

recirculation of the mixed air throughout the office building. Thus, the formaldehyde 

concentration in any given work space can be affected by the formaldehyde concentration in 

other sections of the office building. The mathematical modeling does not account for this 

effect.

4.5.4.1 Determination of a Best Estimate for Indoor Air Concentration

The best estimate exposure concentrations, ADC, and LADC results are presented in Table 4-26. 

The best estimate exposure concentrations for the baseline and each analytical option were 

determined by averaging the following values: the midpoint of the intermediate range of 

concentrations for open plan workstations and the midpoint of the intermediate range of 

concentrations for private office workstations. The midpoints of the intermediate ranges of 

concentration estimates were used for the following reasons. First, all of the high-end 

concentration estimates at the baseline are on the order of or greater than 0.1 ppm for both 

workstation types. Indoor air in buildings with a formaldehyde concentration of 0.1 ppm is 

considered highly polluted air. It is not likely that typical office buildings will have workstations 

with highly polluted air at the baseline even if the buildings do use new furniture. Second, the 

low-end concentration estimates at the baseline and for each analytical option are on the order of 

0.003 to 0.005 ppm for both workstation types. The ambient air formaldehyde concentration for 

commercial land use areas used for this assessment is 3.26 μg/m3or about 0.00265 ppm. The 
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low-end concentration estimates are the same order of magnitude as the ambient air 

formaldehyde concentration. It is likely that formaldehyde concentrations in office buildings at 

the baseline would be greater than the ambient air formaldehyde concentration. Therefore, the 

intermediate range of concentration estimates is more reasonable in comparison with the lowand high-end ranges and was used to derive the best estimate concentrations. The midpoints of 

the intermediate ranges for both workstation types are averaged together to provide the best 

estimate concentrations. The best estimate reduction from baseline, ADC, and LADC values are 

calculated from the best estimate concentration values. It is assumed that office workers spend 

most of their time at workstations. Therefore, this indoor air concentration is the exposure 

concentration for office workers. As described in Appendix E, ADC and LADC were calculated 

assuming exposure duration of 8 hours per day and exposure frequency of 250 days per year over 

40 working years per lifetime for ADC and over a lifetime of 70 years for LADC.

Similarly as with the CWP fabrication results, the office building results show that the maximum 

formaldehyde exposure concentration decreases as lower (more stringent) emission standards are 

implemented. Again, the minimum exposure concentrations in Table 4-22 and Table 4-23

remain constant throughout the different analytical options due to the presence of NAFcompliant products at the baseline. The office building results in Table 4-26 show the most 

significant reduction in exposure concentration from the NAF emission limits.
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Table 4-22. Results for Calculation of What-If Indoor Air Formaldehyde Concentrations

for Each Analytical Option

Case

CWP 

Type Low-End of Range

Intermediate 

Value

High-End of 

Range

Open Plan Workstations (ppm)1

Baseline 

HWPW 0.0035 0.0265 0.2002

PB 0.0035 0.0346 0.4680

MDF 0.0053 0.0732 1.0089

Analytical Option (1): CARB 

Phase 1 

HWPW 0.0035 (0%) 0.0167 (-36.8%) 0.0729 (-63.6%)

PB 0.0035 (0%) 0.0328 (-5.2%) 0.1117 (-76.1%)

MDF 0.0053 (0%) 0.0705 (-3.7%) 0.2833 (-71.9%)

Analytical Option (2): FSCWPA 

/ CARB Phase 2 

HWPW 0.0035 (0%) 0.0143 (-45.9%) 0.0414 (-79.3%)

PB 0.0035 (0%) 0.0323 (-6.7%) 0.0717 (-84.7%)

MDF 0.0053 (0%) 0.0701 (-4.2%) 0.1670 (-83.4%)

Analytical Option (3): NAF 

HWPW 0.0035 (0%) 0.0099 (-62.5%) 0.0184 (-90.8%)

PB 0.0035 (0%) 0.0099 (-71.3%) 0.0184 (-96.1%)

MDF 0.0053 (0%) 0.0346 (-52.8%) 0.0728 (-92.8%)

Private Office Workstations (ppm)1

Baseline 

HWPW 0.0030 0.0130 0.0719

PB 0.0030 0.0165 0.1659

MDF 0.0036 0.0332 0.3555

Analytical Option (1): CARB 

Phase 1 

HWPW 0.0030 (0%) 0.0087 (-32.5%) 0.0273 (-62.0%)

PB 0.0030 (0%) 0.0157 (-4.7%) 0.0409 (-75.3%)

MDF 0.0036 (0%) 0.0320 (-3.5%) 0.1011 (-71.6%)

Analytical Option (2): FSCWPA 

/ CARB Phase 2 

HWPW 0.0030 (0%) 0.0077 (-40.6%) 0.0163 (-77.4%)

PB 0.0030 (0%) 0.0155 (-6.1%) 0.0269 (-83.8%)

MDF 0.0036 (0%) 0.0318 (-4.0%) 0.0603 (-83.0%)

Analytical Option (3): NAF 

HWPW 0.0030 (0%) 0.0058 (-55.3%) 0.0082 (-88.6%)

PB 0.0030 (0%) 0.0058 (-64.8%) 0.0082 (-95.1%)

MDF 0.0036 (0%) 0.0165 (-50.4%) 0.0273 (-92.3%)

Note: For the purpose of this assessment, “intermediate” is defined as a value in-between the low-end and the highend (see Section 3.3.1.2).

1

For the analytical options, the percent decrease from the corresponding baseline value is given in parentheses. For 

example, for Analytical Option (1) for open plan workstations, the high-end value for HWPW is 0.0729 ppm - a 

63.6 percent decrease from the high-end baseline value.
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Table 4-23. Combined (for All CWP) Results: Calculated What-If Indoor Air 

Concentrations at the Baseline and for the Analytical Options

Open Plan Workstations1

Case Intermediate (ppm) Low End (ppm) High End (ppm)

Baseline 0.0265 - 0.0732 0.0035 - 0.0053 0.2002 - 1.0089

Phase 1

0.0167 (-37.0%) -

0.0705 (-3.7%) 0.0035 (0%) - 0.0053 (0%) 0.0729 (-63.6%) - 0.2833 (-71.9%)

FSCWPA / 

Phase 2

0.0143 (-46.0%) -

0.0701 (-4.2%) 0.0035 (0%) - 0.0053 (0%) 0.0414 (-79.3%) - 0.167 (-83.4%)

NAF 0.0099 (-62.6%) -

0.0346 (-52.7%) 0.0035 (0%) - 0.0053 (0%) 0.0184 (-90.8%) - 0.0728 (-92.8%)

Private Office Workstations1

Case Intermediate (ppm) Low End (ppm) High End (ppm)

Baseline 0.013 - 0.0332 0.003 - 0.0036 0.0719 - 0.3555

Phase 1

0.0087 (-33.1%) - 0.032 

(-3.6%) 0.003 (0%) - 0.0036 (0%) 0.0273 (-62.0%) - 0.1011 (-71.6%)

FSCWPA / 

Phase 2

0.0077 (-40.8%) -

0.0318 (-4.2%) 0.003 (0%) - 0.0036 (0%) 0.0163 (-77.3%) - 0.0603 (-83.0%)

NAF 0.0058 (-55.4%) -

0.0165 (-50.3%) 0.003 (0%) - 0.0036 (0%) 0.0082 (-88.6%) - 0.0273 (-92.3%)

1

For the analytical options, the percent decrease from the corresponding baseline value is given in parentheses. For 

example, for Analytical Option (1) for open plan workstations, the minimum of the high-end values is 0.0729 ppm -

a 63.6 percent decrease from the high-end baseline value.

Table 4-24. Combined (for All CWP) Results: Calculated What-If Indoor Air ADCs at the

Baseline and for the Analytical Options

Open Plan Workstations

Case

Intermediate

(μg/m3)

Low End

(μg/m3)

High End

(μg/m3)

Baseline 7.44 - 20.54 0.98 - 1.49 56.17 - 283.1

Phase 1 4.69 - 19.78 0.98 - 1.49 20.46 - 79.49

FSCWPA / 

Phase 2

4.01 - 19.67 0.98 - 1.49 11.62 - 46.86

NAF 2.78 - 9.71 0.98 - 1.49 5.16 - 20.43

Private Office Workstations

Case

Intermediate 

(μg/m3)

Low End 

(μg/m3)

High End 

(μg/m3)

Baseline 3.65 - 9.32 0.84 - 1.01 20.17 - 99.75

Phase 1 2.44 - 8.98 0.84 - 1.01 7.66 - 28.37

FSCWPA / 

Phase 2

2.16 - 8.92 0.84 - 1.01 4.57 - 16.92

NAF 1.63 - 4.63 0.84 - 1.01 2.3 - 7.66
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Table 4-25. Combined (for All CWP) Results: Calculated What-If Indoor Air LADCs at 

the Baseline and for the Analytical Options

Open Plan Workstations

Case

Intermediate

(μg/m3)

Low End

(μg/m3)

High End

(μg/m3)

Baseline 4.25 - 11.74 0.56 - 0.85 32.1 - 161.8

Phase 1 2.68 - 11.3 0.56 - 0.85 11.69 - 45.42

FSCWPA / 

Phase 2

2.29 - 11.24 0.56 - 0.85 6.64 - 26.78

NAF 1.59 - 5.55 0.56 - 0.85 2.95 - 11.67

Private Office Workstations

Case

Intermediate

(μg/m3)

Low End

(μg/m3)

High End

(μg/m3)

Baseline 2.08 - 5.32 0.48 - 0.58 11.53 - 57.00

Phase 1 1.39 - 5.13 0.48 - 0.58 4.38 - 16.21

FSCWPA / 

Phase 2

1.23 - 5.1 0.48 - 0.58 2.61 - 9.67

NAF 0.93 - 2.65 0.48 - 0.58 1.31 - 4.38

Table 4-26. Best Estimate of What-If Formaldehyde Exposure Concentration at the

Baseline and for the Analytical Options

Case

Best Estimate

Concentration1

(ppm)

Reduction 

from Baseline 

(%)

ADC 

(μg/m3)

LADC 

(μg/m3)

Baseline 0.0365 -- 10.23 5.85

Phase 1 0.0320 -12.3 8.97 5.13

FSCWPA / 

Phase 2

0.0310 -15.1 8.69 4.97

NAF 0.0167 -54.2 4.69 2.68

1 The best estimate concentration is the average of the following two values: the 

midpoint of the intermediate range for open plan workstations and the midpoint 

of the intermediate range for private office workstations. The reduction from 

baseline, ADC, and LADC values are calculated from the best estimate

concentration value.

4.5.5 Dermal Exposures during Commercial Use

Dermal exposures to CWPs are not quantifiable using the EPA dermal exposure models for 

liquids and solids.
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5. UNCERTAINTIES IN ASSESSMENT RESULTS

5.1 Uncertainties in Assessment Results for Composite Wood Product Manufacturing, 

Fabrication, Wholesale, Retail, and Office Buildings

This section discusses the uncertainties in the results of the assessment of occupational 

formaldehyde exposure at composite wood product manufacturing, fabrication, wholesale, and 

retail sites, and office buildings. Baseline indoor air concentration and the effect of the 

analytical options on it were assessed quantitatively for CWP fabrication and office buildings 

only, and therefore the discussion of uncertainty in the assessment of indoor air concentration is 

limited to these life cycle stages and is presented in Section 5.1.1 and Section 5.1.2, respectively. 

Uncertainty in the assessed number of production workers for the manufacturing and fabrication 

life cycle stages and in the number of employees in the wholesale and retail life cycle stages is 

discussed in Section 5.3.

Dermal exposures were assessed quantitatively for manufacturing. Due to data gaps in 

information on the free (un-reacted) formaldehyde content in resins that will be used at baseline 

and for each analytical option, only pre-baseline dermal exposures were estimated for 

manufacturing. The dermal exposure level at the baseline and for the analytical options was 

assumed to be equal to the estimated pre-baseline dermal exposure level. This assumption would 

overestimate the dermal exposures at baseline and the analytical options if the free formaldehyde 

content of resins is lower at the baseline and for the analytical options.

5.1.1 Uncertainty in the Estimates of Indoor Air Concentration for Composite Wood Product 

Fabrication

The assessment of site-average formaldehyde indoor air concentrations for composite wood 

product fabrication relies on a mass balance approach that equates the emission rates due to offgassing to the rate at which airborne formaldehyde is exhausted from the work space through 

ventilation. As discussed in Section 3.3.1.1 and Appendix E, indoor air concentration was 

calculated from the four parameters in the mass balance equation, which are emitting surface 

area, emission rate due to off-gassing, effective ventilation rate, and ambient air formaldehyde 

concentration, as well as the assumption of a well-mixed box for the fabrication site. As 

discussed in Section 3.3.1.1, due to data gaps on the values of these four parameters at 

representative CWP fabrication sites, a range of what-if values for indoor air concentration was 

calculated from bounding values for the ranges of three of the four parameters. CWP fabrication 

sites were assumed to contain only HWPW, or only PB, or only MDF in this what-if approach. 

As discussed in Section 3.3.1.1, there is considerable uncertainty in the range of values for 

emitting surface area, and some uncertainty in the ranges of values for effective ventilation rate

and for emission rates. Therefore, there is uncertainty in the calculated ranges of baseline indoor 

air concentration due to off-gassing and the effect of the analytical options on the baseline 

concentrations. It is not possible to determine the direction of uncertainty (i.e., whether the 

estimated values for indoor air concentration are an underestimate or an overestimate).

Although IMIS data and emission rates for the pre-baseline period are available, they cannot be 

used to perform a general validation of the calculation method nor can this information be used 
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to estimate values for effective ventilation rate and emitting surface area for the following 

reasons:

 The calculated assessment results are only an estimate of airborne concentrations 

due to off-gassing. IMIS monitoring data are intended to be measurements of 

aggregate airborne concentrations and do not contain information on the source or 

sources of exposure and the contributions to the aggregate concentrations where 

different sources of exposure existed when the monitoring occurred.

 It is uncertain as to whether the IMIS monitoring data are representative of the 

exposures experienced by workers in the CWP fabrication industries during the 

pre-baseline period (see Section 5.2.1).

The modeling method used to estimate formaldehyde concentrations in this assessment only

accounts for the off-gassing of formaldehyde from the three composite wood products of interest

and the formaldehyde concentration in ambient air. As discussed in Section 4.2.1, there is some 

indication that sources other than the three CWPs of interest may contribute to formaldehyde 

airborne concentrations. The number of sites in which these other sources may be present, the 

number of workers that would be potentially exposed to emissions from these other sources, and 

the magnitude of such potential exposure are not known. The assessment results for the baseline 

and analytical options are not an estimate of aggregate indoor air concentration where other 

sources of formaldehyde exist.

5.1.2 Uncertainty in the Estimates of Indoor Air Concentration for Office Buildings

Data on the composition of composite wood products in office furniture was not found. 

Therefore, the composition of each of the three types of composite wood products in office

workstations is unknown. As discussed in Section 3.3.1.2, panels and work surfaces were 

assumed to be wholly made of composite wood products. Information on the type and extent of 

overlays on the composite wood products was also not found. The effect of uncertainty about 

the composition of CWPs in office workstations and the overlays on these CWPs on the 

assessment of baseline exposure and the effect of analytical options on baseline exposure are 

undetermined.

The office building method uses emission rates for new composite wood products and do not 

account for the decay of emissions with time. Therefore, this method to estimate formaldehyde 

concentrations in office buildings only accounts for new office furniture and does not account for 

the decay of emission rates with time. Data to describe the decay of emission rates with time in 

office buildings were not found through the literature search. Therefore, the estimated airborne 

concentrations presented in this assessment are only applicable to offices with new office 

furniture.

The method used simplifies the complex nature of office building ventilation systems. Typically 

in these systems, outdoor air is mixed with a recirculation stream of indoor air prior to being 

supplied to the various ventilation zones. The return air from these ventilation zones is mixed 

and then a stream is split for recirculation and mixing with the outdoor air while the balance is 

exhausted. Therefore, the office environment model neglects the effect of one exposure zone on 

another resulting from the recirculation of indoor air or the movement of air directly between 
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exposure zones without passing through the ventilation system. The uncertainty in the results 

due to neglecting the effect of one exposure zone on another is uncertain and cannot be 

quantified without a detailed, rigorous mathematical model with detailed supporting monitoring 

data.

Although monitoring data from the BASE study and emission rates for the 2002 to 2009 prebaseline period are available, they cannot be used to perform a general validation of the 

calculation method or a validation of the assumed values for the surface area covered by overlay

materials and their associated barrier effectiveness. The ages of the office furniture workstations

present in the buildings studied in the BASE study are unknown. It is likely that much of the 

office furniture that contributed to the exposure concentrations observed in the BASE study were 

of various ages and not representative of new office furniture. The emission rates for CWP that 

are components of this aged office furniture at the time of monitoring are not known because 

their initial value when these CWP were new is not known and the extent of their decay with 

time until the time of monitoring is not known. Furthermore, even where monitoring occurred 

for new office furniture (a situation that cannot be determined from the BASE study data), the 

emission rates of CWPs used in this furniture is unknown. Hence, model validation is not 

possible using the BASE study data because the emission rates of CWPs present in office 

furniture in the monitored buildings is unknown.

5.2 Uncertainties in Pre-Baseline Monitoring Data

5.2.1 OSHA IMIS Data

This section discusses uncertainties associated with OSHA IMIS monitoring data. The 

uncertainties discussed below apply to the IMIS data collected for each life cycle stage (CWP 

manufacturing, fabrication, wholesale, and retail). The major conclusion of this discussion is 

that it is uncertain whether the collected IMIS data are representative of the formaldehyde 

exposure concentrations that occurred during the pre-baseline period of 2002 to 2009 in facilities 

of the industries within each life cycle stage assessed in this report.

Representativeness of IMIS Data

The representativeness of the measured exposure concentrations in IMIS for the entire 

population of exposed workers is examined below. The discussion below presents statistics of 

the IMIS data obtained for the CWP fabrication life cycle stage only since a larger amount of 

data were obtained for this life cycle stage. Very few data were obtained for the CWP 

manufacturing, wholesale, and retail life cycle stages.

Table 5-1 presents data on the total number of unique OSHA inspections conducted within each 

NAICS industry code of the CWP fabrication life cycle stage. A total of 78 inspections were 

conducted at 77 facilities between 2002 and 2009, indicating that most inspections occurred at 

separate facilities. The table compares the number of inspected facilities to the total number of 

facilities for that particular industry sector based on estimates from the 2007 Economic Census. 

The sample size (the number of inspected facilities) ranges from zero to 19 over all of the 

industries. Sampling theory guarantees an accurate degree of confidence in the estimate of a 

population mean when the sample size is at least 30 samples. When at least 30 samples are 
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obtained, it is not required for the population to have a normal distribution to guarantee an 

accurate degree of confidence. However, accuracy does require that the samples are random 

(Walpole 2002a).

Table 5-1. Number of OSHA Inspections at CWP Fabrication Facilities Compared to the 

Maximum Number of Facilities from the U.S. Economic Census

NAICS Description

2007 U.S. Economic 

Census Data OSHA IMIS Data (2002 to 2009)

Maximum Number 

of Establishments

Number of 

Unique 

Inspections

Number of

Unique 

Facilities

321911 Wood window & door 

Manufacturing 1,494 4 4

321918 Other millwork (including 

flooring) 2,101 9 9

321991 Manufactured home (mobile 

home) Manufacturing 376 0 0

321999 All other misc. wood product 

Manufacturing 1,964 8 8

337110 Wood kitchen cabinet & 

countertop Manufacturing 9,683 20 19

337121 Upholstered household 

furniture Manufacturing 1,633 4 4

337122

Nonupholstered wood 

household furniture 

Manufacturing

3,428 12 12

337124 Metal household furniture 

Manufacturing 330 0 0

337127 Institutional furniture 

Manufacturing 782 5 5

337129

Wood television, radio, & 

sewing machine cabinet 

Manufacturing

270 0 0

337211 Wood office furniture 

Manufacturing 457 6 6

337212

Custom architectural 

woodwork & millwork 

Manufacturing

2,228 2 2

337214 Office furniture (except 

wood) Manufacturing 289 2 2

337215 Showcase, partition, shelving, 

& locker Manufacturing 1,377 5 5

339950 Sign manufacturing 6,383 0 0

336213 Motor home Manufacturing 80 1 1

336214 Travel trailer & camper 

Manufacturing 862 0 0

Total 33,737 78 77
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For each fabrication industry, less than 30 samples were obtained between 2002 and 2009. 

Therefore, an accurate degree of confidence in the estimate of the population mean cannot be 

guaranteed without knowledge of whether the population is represented by a normal distribution. 

While all of the fabrication industries in Table 5-1 can be aggregated together to yield a sample 

size of 78 (the total number of inspections), such aggregation would not resolve the second 

criterion for an accurate degree of confidence: random sampling. Examination of the 

randomness of the sampling is made using knowledge of how OSHA conducts inspections.

Lavoue et al. (Lavoue 2008a) analyzed formaldehyde exposures from U.S. industries from the 

OSHA IMIS database using data from 1979 to 2001. The authors note that exposures in IMIS 

have long been suspected to not be representative of exposures in the U.S. population. The 

authors found the IMIS exposures to mainly result from complaints, referrals, or programs 

targeted at specific industrial sectors. However, the authors also note that, “within industries, 

available evidence suggests that bias relating to selecting companies with high exposure levels 

during complaint visits should be of small amplitude”. The pre-baseline exposure monitoring 

data presented in the assessment were examined to further evaluate any selection bias.

OSHA may initiate an inspection due to a referral by a federal or state government agency or a 

worker complaint regarding workplace hazards. Alternatively, OSHA may inspect 

establishments that were selected under the agency’s programmed inspection plan. The 

“inspection types” for the compiled IMIS data are: (1) referral (15%); (2) complaint (58%); (3) 

program-planning (25%); and (4) follow-up (2%) (see Appendix A, Definition of Terms for 

exposure and inspection types). These inspection types are further discussed below.

The Site-Specific Targeting program is OSHA’s main programmed inspection plan for nonconstruction workplaces that have 40 or more workers. The selection criteria involve several 

parameters such as the number of injury and illness cases, the number of days away from work, 

and the number of workers who receive job transfers or work restrictions due to injury or illness. 

In addition to the Site-Specific Targeting program, OSHA also implements both national and 

local emphasis inspection programs to target high-risk hazards and industries. Some areas that 

OSHA focuses on are amputations, lead, crystalline silica, shipbreaking, trenching and 

excavations, process safety management in petroleum refineries, hexavalent chromium, diacetyl, 

recordkeeping and combustible dust (OSHA 2010a). Programmed and planned inspections may

or may not be considered random. If a particular industry were chosen for a programmed or 

planned inspection, the facilities inspected within the selected industry would have been chosen 

randomly. However, it is possible a facility was specifically chosen as part of a program or plan 

if the facility had a history of problems or hazards, in which case the choice of facility would not 

have been random.

Complaint and referral inspection types would not be considered random, since OSHA inspected 

the given facility based on evidence that a problem existed from an employee or other agency 

with knowledge of the facility. It is difficult to determine whether follow-up inspections would 

be considered random without knowing the inspection type for the original inspection.

Although OSHA typically inspects establishments with potential workplace hazards, these 

hazards may or may not be related to formaldehyde overexposure. For example, OSHA may

inspect an establishment that manufactures PB after an employee files a complaint concerning 
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dust exposure. Since the establishment processes formaldehyde-containing materials, personal 

monitoring for formaldehyde was also conducted during the inspection although there may or 

may not be a formaldehyde overexposure. Therefore, it cannot be assumed that a facility 

inspected by OSHA through one of the programs described above is necessarily an outlying or 

atypical facility with high formaldehyde exposures.

It is uncertain whether the programmed and planned inspections included in the IMIS data 

presented in this assessment randomly selected the inspected facilities. Therefore, it cannot be 

concluded whether any of the OSHA IMIS data are the result of random sampling. In 

conclusion, it is uncertain whether OSHA IMIS monitoring data are representative of the 

exposure concentrations of formaldehyde in the industries from which the data were obtained.

Intra-Site Variability in Monitored Indoor Air Concentration

This subsection discusses the variability in the measured indoor air concentrations during a 

single inspection at a single facility. This discussion is limited to CWP fabrication sites since 

only this life cycle stage had an adequate amount of data to allow this analysis.

The variation in indoor air concentration of fabricator sites was considered by examination of 

IMIS monitoring data. Figure 5-1 through Figure 5-8 display formaldehyde indoor air

concentrations from OSHA IMIS for composite wood product fabricators in which multiple 

worker activities were monitored for a single site. The graphs display formaldehyde 

concentration as a function of monitored worker activity. CSHO stands for Compliance Safety 

and Health Officer and represents the exposures for the inspector. Worker activities with only a 

single exposure level are shown with only a median exposure concentration measurement.

These figures illustrate that many of these site inspections resulted in similar exposure

concentrations for all monitored worker activities (exposure level for the worker activity with the 

highest exposure level is typically greater than the exposure level of the worker activity with the 

lowest exposure level by up to approximately 100%). However, for some sites, there are worker 

activities with greater variation than this, including the frame operator at Armstrong Cabinets, 

the painter U cell at The Gunlocke Company, and the August 25th auto spray line at Silver 

Street. Most of these have higher values than the other measurements. Most of the pre-baseline 

monitoring data presented in the assessment consist of multiple measurements for a single 

worker activity at a given site. There is considerable variability in the monitored worker 

activities from site to site.

In conclusion, intra-site variability in the monitored exposure level ranges from small to as much 

as 100% or greater based on examination of IMIS data for which multiple worker activities at a 

single site were monitored.
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Figure 5-1. TWA Exposures from OSHA IMIS for a Single Inspection for Armstrong 

Cabinets (NAICS 337110)

Figure 5-2. TWA Exposures from OSHA IMIS for a Single Inspection for Mid Continent 

Cabinetry (NAICS 337110)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Laminator Tyler Operator Frame Operator Painter

Exposure Level (ppm)

Minimum

Median

Maximum

0

0.005

0.01

0.015

0.02

0.025

Assember I Sealer Finisher I Finisher II Sprayer I Sprayer II

T

WA

Exposure Level (ppm)

Minimum

Median

Maximum
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Figure 5-3. TWA Exposures from OSHA IMIS for a Single Inspection for Benvenuti and 

Stein (NAICS 337122)

Figure 5-4. TWA Exposures from OSHA IMIS for a Single Inspection for Ameriwood 

Industries (NAICS 337122)

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

Spray Painter Cabinet Finisher CSHO

Exposure Level (ppm)

Minimum

Median

Maximum

0

0.02

0.04

0.06

0.08

0.1

0.12

Autodrill Selco #2 Foiler CSHO

Exposure Level (ppm)

Minimum

Median

Maximum
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Figure 5-5. TWA Exposures from OSHA IMIS for Two Inspections for The Gunlocke 

Company (NAICS 337211)

Figure 5-6. TWA Exposures from OSHA IMIS for Two Inspections for Silver Street 

(NAICS 337211)

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

Inspector U Cell Laborer U Cell Sander U Cell Sander W Cell Sprayer Booth #7 Painter U Cell

July 1, 2005 August 9, 2005

Exposure Level (ppm)

Minimum

Median

Maximum

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Panel Saw Operator Auto Spray Line Router Operator Auto Spray Line

August 11, 2004 August 25, 2004

Exposure Level (ppm)

Minimum

Median

Maximum
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Figure 5-7. TWA Exposures from OSHA IMIS for a Single Inspection for The 

Commercial Furniture Group (NAICS 337127)

Figure 5-8. TWA Exposures from OSHA IMIS for a Single Inspection for Parenti & 

Raffaelli (NAICS 321918)

0

0.02

0.04

0.06

0.08

0.1

0.12

Sealer Booth Fabric Store Room Fabric Cutter

Exposure Level (ppm)

Exposure (single measurement)

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

Cutter Assembler Cabinet Maker

Exposure Level (ppm)

Minimum

Median

Maximum
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5.2.2 BASE Study Monitoring Data

A total of 100 commercial and public office buildings were monitored in the BASE study 

between 1994 and 1998. To determine the representativeness of the BASE sample of office 

buildings, the BASE study authors compared this sample to larger samples of U.S. office 

buildings using data collected by the Energy Information Administration of the U.S. Department 

of Energy through the 1995 Commercial Building Energy Consumption Survey (CBECS). The 

BASE study authors were able to perform two comparisons: 1) a comparison of the BASE 

buildings to a larger sample of large urban office buildings; and 2) a comparison of the BASE 

buildings to a larger sample of all U.S. office buildings. The BASE study authors determined 

that the BASE buildings are most similar to the CBECS sample of large, urban office buildings; 

specifically, buildings with more than 50 occupants in Metropolitan Statistical Areas (MSAs)12

(BASE 2001a). The BASE study authors note that the BASE buildings were selected from cities 

with populations greater than 100,000. However, MSAs are urbanized areas with populations 

greater than 50,000. Therefore, there is a slight discrepancy in the comparison of the 

surrounding populations of the BASE study buildings and the large, urban office buildings from 

CBECS. Furthermore, the BASE buildings were selected from downtown areas. The BASE 

study authors found the BASE buildings to be three to four times larger than the CBECS sample 

of large, urban office buildings. Consistent with this finding, a separate survey conducted by the 

Building Owners and Managers Association (BOMA) found that downtown office buildings tend 

to be larger than other metropolitan area office buildings. Although these differences in 

surrounding population and building size are noted, the BASE study authors found that BASE 

study buildings most likely represent large, urban office buildings (BASE 2001a).

Based on the CBECS sample of all U.S. office buildings, the BASE buildings do not represent 

the entire population of all U.S. office buildings well. However, the BASE study authors note 

that, although the large, urban office buildings account for only 11% (or about 80,000) of all 

U.S. office buildings (about 705,000), this building type represents 73% (or about 19,428,229) of 

all U.S. office workers (about 26,563,566) according to the CBECS data (BASE 2001a). 

Therefore, the BASE study office buildings are most similar to the office building type (large, 

urban office buildings) that house approximately 73% of all U.S. office workers. Note that these 

statistics are based on survey data from 1995. It is unknown how these statistics have changed 

since 1995. The second criterion, random sample selection, is analyzed next.

The building selection criteria described in the BASE study documents indicate that the BASE 

study did randomly select office buildings for study. Buildings were selected randomly in 

randomly selected cities. The study authors selected buildings in ten climatic regions of the U.S.

(BASE 2001a; NIST 2008a).

Whether the measured formaldehyde concentrations are representative of year-round 

concentrations in these buildings is also analyzed. The BASE study focused its building 

measurements during the winter and summer months. Building ventilation systems are more 

likely to operate at minimum outdoor air ventilation rates during the winter and summer to 

 

12 The U.S. Office of Management and Budget defines a Metropolitan Statistical Area (MSA) as: “a county or group 

of contiguous counties that contain (1) at least one city of 50,000 inhabitants or more (‘twin cities’ with a combined 

population of at least 50,000 inhabitants) or (2) an urbanized area of at least 50,000 inhabitants and a total MSA 

population of at least 100,000 (75,000 in New England)” (BASE 2001a).
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minimize the amount of air heating or cooling required. NIST conducted an analysis of the 

ambient temperatures recorded during the BASE study and concluded that approximately 62% of 

the data could possibly correspond to buildings operating with minimum outdoor air ventilation 

rates (NIST 2008a). However, the building operations during winter and summer were not 

compared against their operations during spring or autumn. Therefore, it cannot be concluded 

for certain whether buildings were operating at lower outdoor air ventilation rates during the 

BASE study. NIST additionally analyzed the BASE study data on the ventilation system designs 

and the measured ventilation rates. NIST concluded that the ratio of the minimum outdoor air 

ventilation rate to total supply air ventilation based on the ventilation system designs had an 

average value of 0.19 and a median of 0.12. The observed ratio of actual outdoor air ventilation 

rate to total supply air ventilation had an average value of 0.38 and a median of 0.22 (NIST 

2008a). This observation illustrates that, in general, many of the studied buildings operated at 

outdoor air ventilation rates greater than the system design minimum.

In conclusion, it has been established that the studied buildings are representative of large, urban 

commercial and public office buildings from the time frame of the study. However, it is 

uncertain whether the measured formaldehyde concentrations are representative of 

concentrations that occurred in these buildings during an entire year or if they are only 

representative of winter and summer concentrations.

5.3 Uncertainty in Number of Production Workers and Employees

U.S. Census data on the number of production workers (for CWP manufacturing and fabrication) 

and employees (for wholesale and retail) are presented for the NAICS industry sectors associated 

with each life cycle stage. While these data were not used for the quantitative assessment, they

were presented to indicate the total number of production workers and employees potentially

exposed to formaldehyde emissions from composite wood products. These data likely represent 

an overestimation for the following reasons.

Census data represent the overall statistics for the entire industry sector. Additionally, Census 

data do not contain specific information on the type of composite wood products associated with 

these statistics. Some sites within these industry sectors may not manufacture, use, or sell the 

composite wood products of interest.

For any given site, it is uncertain whether the breathing zone for all production workers or 

employees would be affected by the off-gassing of formaldehyde from the composite wood 

products of interest. Therefore, there is some uncertainty in assessing whether the number of 

production workers and employees presented in this assessment is an overestimate. However, 

for the reasons listed above, the number of production workers and employees from U.S. Census 

data is likely an overestimate of the actual exposed population who would be affected by the 

regulation. More specific information on the actual exposed population is not available.
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6. REFERENCES

Alexandersson 1982a. Alexandersson, R.; Hedenstierna, G.; Kolmodin-Hedman, B. Exposure to formaldehyde: effects on pulmonary

function. Arch. Environ. Health 1982, 37 (5), 279-284.

ASTM 2002a. Standard Test Method for Determining Formaldehyde Concentrations in Air and Emission Rates from Wood Products Using a 

Large Chamber: ASTM E 1333-96 (Reapproved 2002); ASTM International: West Conshohocken, PA, 2002.

ATSDR 1999a. Toxicological Profile for Formaldehyde; Agency for Toxic Substances and Disease Registry (ATSDR): July 1999.

ATSDR 2010a. Addendum to the Toxicological Profile for Formaldehyde. Agency for Toxic Substances and Disease Registry (ATSDR): 

Atlanta, GA, October 2010.

AWFS 2009a. California Air Resources Board; Masco Retail Cabinet Group; Composite Panel Association. Update on California’s 

Composite Wood Products Regulations, Association of Woodworking and Furnishing Suppliers (AWFS) Show, Las Vegas, 

Nevada, July 18, 2009.

Baldwin 1995a. Baldwin, Richard F. Plywood and Veneer-Based Products: Manufacturing Practices; Miller Freeman Books: 1995.

Ballarin 1992a. Ballarin, Cinzia; Sarto, Franco; Giacomelli, Luciano; Bartolucci, Giovanni Battista; Clonfero, Erminio. Micronucleated cells 

in nasal mucosa of formaldehyde-exposed workers. Mutation Research 1992, 280 (1), 1-7.

BASE 1998a. U.S. Environmental Protection Agency (USEPA). Building Assessment Survey and Evaluation (BASE) Study: Volatile 

Organic Compounds Master List. http://www.epa.gov/iaq/base/voc_master_list.html (accessed June 16, 2009).

BASE 2001a. Environmental Health & Engineering, Inc. Summary and Analysis Report of the BASE Study Building Selection Process; 

11995; Newton, MA, 2001.

Battelle 1996a. Kelly, Thomas J. Determination of Formaldehyde and Toluene Diisocyanate Emissions from Indoor Residential Sources; 

Battelle: Columbus, OH, November 1996.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page 95

BIFMA 2007a. Standard Test Method for Determining VOC Emissions from Office Furniture Systems, Components and Seating; 

ANSI/BIFMA M7.1-2007; Business and Institutional Furniture Manufacturer’s Association (BIFMA) International: Grand 

Rapids, MI, September 2007.

BIFMA 2007b. Standard for Formaldehyde and TVOC Emissions of Low-emitting Office Furniture Systems and Seating; ANSI/BIFMA 

X7.1-2007; Business and Institutional Furniture Manufacturer’s Association (BIFMA) International: Grand Rapids, MI, 

August 2007.

CARB 2007a. Proposed Airborne Toxic Control Measure to Reduce Formaldehyde Emissions from Composite Wood Products: Initial 

Statement of Reasons for Proposed Rulemaking (ISOR); California Air Resources Board (CARB): Sacramento, CA, March 

2007.

Carter 2007a. Carter, Randal D.; Zhang, Jianshun S. Definition of Standard Office Environments for Evaluating the Impact of Office 

Furniture Emissions on Indoor VOC Concentrations. ASHRAE Transactions. 2007, 113, 466-477.

Census 2007a. 2007 Economic Census [Online]; U.S. Census Bureau, 2007. http://www.census.gov/econ/census07/.

Chimar Hellas undated. Update on the formaldehyde release from wood-based panels; Chimar Hellas S.A.: Undated.

http://www.chimarhellas.com/wp-content/uploads/2008/07/formaldehyde_2008.pdf (accessed February 12, 2009).

Chung 2000a. Chung, K.Y.; Cuthbert, R.J.; Revell, G.S.; Wassel, S.G.; Summers, N. A study on dust emission, particle size distribution and 

formaldehyde concentration during machining of medium density fibreboard. Ann. Occup. Hyg. 2000, 44, 455-466.

CPA 2003a. VOC Emission Barrier Effects of Laminates, Overlays and Coatings for Particleboard, Medium Density Fiberboard (MDF) and 

Hardboard: Technical Bulletin; Composite Panel Association (CPA): Gaithersburg, MD, 2003.

CPA 2007a. Laminating Composite Panels: Technical Bulletin; Composite Panel Association (CPA): Gaithersburg, MD, 2007.

CPA 2008a. 2007 North American Downstream Market Report; Composite Panel Association (CPA): Leesburg, VA, 2008.

CPA 2009a. Meeting Summary – Discussion with CPA in Response to Comments Submitted to Formaldehyde ANPR Docket; Eastern 

Research Group, Inc.: Chantilly, VA, June 18, 2009.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page 96

CPSC 1997a. An Update on Formaldehyde: 1997 Revision; CPSC Document # 725; Consumer Product Safety Commission (CPSC): 

Washington, DC, 1997. http://www.cpsc.gov/CPSCPUB/PUBS/725.html (accessed January 26, 2009).

Edling 1988a. Edling, C.; Hellquist, H.; Odkvist, L. Occupational exposure to formaldehyde and histopathological changes in the nasal 

mucosa. Br. J. Ind. Med. 1988, 45, 761-765.

Fink 2005a. Fink, Johannes Karl. Reactive Polymers Fundamentals and Applications: A Concise Guide to Industrial Polymers; William 

Andrew, Inc.: Norwich, NY, 2005: pp 288-289.

Fransman 2003a. Fransman, W.; McLean, D.; Douwes, J.; Demers, P.A.; Leung, V.; Pearce, N. Respiratory symptoms and occupational 

exposures in New Zealand plywood mill workers. Ann. Occup. Hyg. 2003, 47, 287-295.

GDNR 1996a. Crumpler, Paul. An Analysis of Pollution Prevention Opportunities and Impediments in the Wood Products Manufacturing 

Sector in Georgia; Georgia Department of Natural Resources (GDNR), Sustainability Division. April 1, 1996 (accessed June 

2, 2009).

Gammage 1988a. Gammage, R.; Matthews, T. Volatile organic compounds in indoor air: types, sources, and characteristics. Environmental 

Progress 1988, 7, 279-283.

Groah 2005a. Groah, William J. Decay or the Decrease in Formaldehyde Concentrations or Emissions over Time and UF-bonded Wood 

Panel Products [Online]; December 21, 2005. http://www.ecobind.com/research/Decay_or_Decrease_in_Emissions.pdf.

Hamilton 1996a. Hamilton, Thomas E.; Alig, Joanne T.; Falk, Robert H. Products from Recycled Fibers – A U.S. Perspective, Proceedings of 

the International Union of Forest Research Organizations (IUFRO) XX World Congress, Tampere, Finland, August 6-12, 

1995. November 21, 1996. http://www.metla.fi/iufro/iufro95abs/rsp21.htm.

HEI 2007a. HEI Air Toxics Review Panel. Formaldehyde. In Mobile-Source Air Toxics: A Critical Review of the Literature on Exposure and 

Health Effects; HEI Special Report 16; Health Effects Institute: Boston, MA, 2007; pp 87-105.

Herbert 1994a. Herbert, F.A.; Hessel, P.A.; Melenka, L.S.; Yoshida, K.; Nakaza, M. Respiratory consequences of exposure to wood dust and 

formaldehyde of workers manufacturing oriented strand board. Arch. Environ. Health 1994, 49 (6), 465-470.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page 97

Hodgson 2007a. Hodgson, Alfred T.; Tannous, Raja S. Meeting the Requirements of the California Composite Wood ATCM Using Chambers 

of Different Sizes; Berkeley Analytical Associates, LLC: Richmond, CA, September 7, 2007.

Horvath 1988a. Horvath, E.P. Jr.; Anderson, H. Jr.; Pierce, W.E.; Hanrahan, L.; Wendlick, J.D. Effects of formaldehyde on the mucous 

membranes and lungs. A study of an industrial population. JAMA. 1988, 259, 701-707.

HPVA 2009a. Howlett, Kip. Hardwood Plywood and Veneer Association (HPVA), Reston, VA. Personal communication, June 11, 2009.

IARC 1995a. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans; Volume 62: Wood Dust and Formaldehyde, IARC 

Working Group on the Evaluation of Carcinogenic Risks to Humans, Lyon, France, October 11-18, 1994; World Health 

Organization: Lyon, 1995.

IARC 2006a. IARC Monographs; Volume 88: Formaldehyde, 2006.

IRSST undated. Exposure to Formaldehyde in the Workplace: Wood Furniture Manufacturing; Institut de recherche Robert-Sauvé en santé et 

en sécurité du travail (IRSST): Montréal, Québec, undated.

Kauppinen and Niemelä 1985a. Kauppinen, T.P.; Niemelä, R.I. Occupational exposure to chemical agents in the particleboard industry. 

Scand. J. Work Environ. Health. 1985, 11, 357-363.

Kim 2007a. Kim, Sumin; Kim, Jin-A; Kim, Hyun-Joong. Application of Field and Laboratory Emission Cell (FLEC) to Determine 

Formaldehyde and VOCs Emissions from Wood-Based Composites. Mokchae Konghak (Journal of the Korean Wood Science 

and Technology). 2007, 35, 24-37.

Kirk-Othmer 2011a. Lehmann, W.F. Wood-Based Composites and Laminates. Kirk-Othmer Encyclopedia of Chemical Technology; John 

Wiley & Sons, Inc.: New York, 2011; pp 1-47.

Koontz 1996a. Koontz, Michael D.; Rector, Harry E.; Cade, Donald R.; Wilkes, Charles R.; Niang, Laura L. Residential Indoor Air 

Formaldehyde Testing Program: Pilot Study; GEOMET Technologies, Inc.: Germantown, MD, March 21, 1996.

Lavoue 2005a. Lavoué, Jérôme; Beaudry, Charles; Goyer, Nicole; Perrault, Guy; Gérin, Michel. Investigation of Determinants of Past and 

Current Exposures to Formaldehyde in the Reconstituted Wood Panel Industry in Quebec. Ann. Occup. Hyg. 2005, 49, 587-

602.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page 98

Lavoue 2008a. Lavoué, Jérôme; Vincent, Raymond; Gérin, Michel. Formaldehyde Exposure in U.S. Industries from OSHA Air Sampling 

Data. Journal of Occupational and Environmental Hygiene 2008, 5, 575-587.

Malaka 1990a. Malaka, T.; Kodama, A.M. Respiratory health of plywood workers occupationally exposed to formaldehyde. Arch. Environ. 

Health 1990, 45 (5), 288-294.

Maloney 1993a. Maloney, T.M. Modern Particleboard & Dry-Process Fiberboard Manufacturing; Miller Freeman Publications, Inc.: San 

Francisco, CA, 1993.

Niemelä and Vainio 1981a. Niemelä, R.; Vainio, H. Formaldehyde exposure in work and the general environment: Occurrence and 

possibilities for prevention. Scand. J. Work Environ. Health 1981, 7, 95-100.

NIOSH 1994a. NIOSH Method 3500: Formaldehyde by Vis (1994). In NIOSH Manual of Analytical Methods, 4th ed. [Online]; Schlecht, 

P.C.; O’Connor, P.F., Eds.; 2003; 3rd Supplement. http://www.cdc.gov/niosh/docs/2003-154/.

NIST 2008a. Persily, Andrew; Gorfain, Josh. Analysis of Ventilation Data from the U.S. Environmental Protection Agency Building 

Assessment Survey and Evaluation (BASE) Study; NISTIR 7145-Revised; National Institute of Standards and Technology

(NIST): November 2008. http://fire.nist.gov/bfrlpubs/build04/art043.html.

OAQPS 1997a. Hanks, Katie; Bullock, David. Site Visit – Champion International Corporation Camden Plywood and Stud Operations, 

Camden, Texas; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of 

Air Quality and Planning Standards (OAQPS): December 1, 1997.

OAQPS 1998a. Hanks, Katie; Nicholson, Becky. Site Visit – Timber Products Company Particleboard and Hardwood Plywood Plant in 

Medford, Oregon; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office 

of Air Quality and Planning Standards (OAQPS): April 16, 1998.

OAQPS 1998b. Hanks, Katie; Nicholson, Becky. Site Visit – Medite Division of Sierra Pine Medium Density Fiberboard Plant in Medford, 

Oregon; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of Air 

Quality and Planning Standards (OAQPS): May 27, 1998.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page 99

OAQPS 1998c. Hanks, Katie; Bullock, David. Site Visit – Triwood, Incorporated Particleboard Plant in Bassett, Virginia; Memorandum 

from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning 

Standards (OAQPS): August 18, 1998.

OAQPS 1999a. Hanks, Katie; Threatt, Brigit; Nicholson, Becky. Summary of Responses to the 1998 EPA Information Collection Request 

(MACT Survey) – Hardwood Plywood and Veneer; Development of a NESHAP for Plywood and Composite Wood Products 

Manufacturing Industry; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA),

Office of Air Quality and Planning Standards (OAQPS): May 19, 1999.

OAQPS 1999b. Bullock, David; Nicholson, Becky; Threatt, Brigit. Site Visit – Willamette Industries, Incorporated, Moncure, North 

Carolina; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of Air 

Quality and Planning Standards (OAQPS): July 27, 1999.

OAQPS 2000a. Hanks, Katie; Bullock, David; Nicholson, Becky. Summary of Responses to the 1998 EPA Information Collection Request 

(MACT Survey) – General Survey; Development of a NESHAP for Plywood and Composite Wood Products Manufacturing 

Industry; Memorandum from Midwest Research Institute to U.S. Environmental Protection Agency (USEPA), Office of Air 

Quality and Planning Standards (OAQPS): April 28, 2000.

OAQPS 2000b. Background Information Document for Proposed Plywood and Composite Wood Products NESHAP; EPA-453/R-01-004; 

U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): Research Triangle 

Park, NC, September 2000.

OAQPS 2002a. Economic Impact Analysis of the Plywood and Composite Wood Products NESHAP: Final Report; U.S. Environmental 

Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): Research Triangle Park, NC, November 

2002.

OAQPS 2002b. Compilation of Air Pollutants Emission Factors, Volume I: Stationary Point and Area Sources (AP-42), Chapter 10, Wood 

Products Industry; U.S. Environmental Protection Agency (USEPA), Office of Air Quality and Planning Standards (OAQPS): 

2002. http://www.epa.gov/ttnchie1/ap42/ch10/.

OECA 1995a. EPA Office of Compliance Sector Notebook Project: Profile of the Wood Furniture and Fixtures Industry; EPA/310-R-95-003; 

U.S. Environmental Protection Agency (USEPA), Office of Enforcement and Compliance Assurance (OECA), Office of 

Compliance: Washington, DC, September 1995.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page 100

OSHA 1999a. Inspection Report for McKnight Plywood, West Helena, AR; Inspection number 123445595; U.S. Department of Labor, 

Occupational Safety and Health Administration (OSHA): Little Rock, AR, August 30, 1999.

OSHA 2000a. Inspection Report for Carolina Curves, Inc., Conover, NC; Inspection number 303713325; North Carolina Department of 

Labor, Division of Occupational Safety and Health: Charlotte, NC, August 15, 2000.

OSHA 2000b. Inspection Report for Jimson Manufacturing Company, Inc., Haleyville, AL; Inspection number 303424014; U.S. Department 

of Labor, Occupational Safety and Health Administration (OSHA): Birmingham, AL, September 20, 2000.

OSHA 2001a. Inspection Report for Marshfield Door Systems, Inc., Marshfield, WI; Inspection number 303864029; U.S. Department of 

Labor, Occupational Safety and Health Administration (OSHA): Madison, WI, November 9, 2001.

OSHA 2001b. Inspection Report for Newood Display Fixtures Manufacturing Company, Eugene, OR; Inspection number 304064835; Oregon 

Department of Consumer and Business Services, Oregon Occupational Safety and Health Division (OR-OSHA): Salem, OR, 

February 15, 2001.

OSHA 2002a. Woodworking eTool [Online]; Occupational Safety and Health Administration (OSHA): April 2002. 

http://www.osha.gov/SLTC/etools/woodworking/index.html (accessed September 7, 2011).

OSHA 2002b. Inspection Report for Parenti & Rafaelli, Ltd, Mount Prospect, IL; Inspection number 305228652; U.S. Department of Labor, 

Occupational Safety and Health Administration (OSHA): Des Plaines, IL, August 1, 2002.

OSHA 2003a. Inspection Report for Bushline, Inc., New Tazewell, TN; Inspection number 306132275; State of Tennessee, Department of 

Labor and Workforce Development, Division of Occupational Safety and Health: Nashville, TN, June 19, 2003.

OSHA 2003b. Inspection Report for Tru-Wood Cabinets, Inc., Ashland, AL; Inspection number 307013250; U.S. Department of Labor, 

Occupational Safety and Health Administration (OSHA): Birmingham, AL, December 5, 2003.

OSHA 2003c. Inspection Report for Simple Designs Manufacturing, Inc., Tualatin, OR; Inspection number 306629171; Oregon Department 

of Consumer and Business Services, Oregon Occupational Safety and Health Division (OR-OSHA): Salem, OR, October 21, 

2003.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page 101

OSHA 2004a. Inspection Report for Armstrong Cabinets, Auburn, NE; Inspection number 306021239; U.S. Department of Labor, 

Occupational Safety and Health Administration (OSHA): Omaha, NE, September 30, 2004.

OSHA 2004b. Inspection Report for England, Inc., New Tazewell, TN; Inspection number 307674051; State of Tennessee, Department of 

Labor and Workforce Development, Division of Occupational Safety and Health: Nashville, TN, June 11, 2004.

OSHA 2004c. Inspection Report for Harris-Tarkett, Inc., Johnson City, TN; Inspection number 307206987; State of Tennessee, Department 

of Labor and Workforce Development, Division of Occupational Safety and Health: Nashville, TN, March 19, 2004.

OSHA 2005a. Inspection Report for Fiberesin Industries, Inc., Oconomowoc, WI; Inspection number 307061689; U.S. Department of Labor, 

Occupational Safety and Health Administration (OSHA): Milwaukee, WI, September 21, 2005.

OSHA 2005b. Inspection Report for Plymart, Inc., Boring, OR; Inspection number 308245372; Oregon Department of Consumer and 

Business Services, Oregon Occupational Safety and Health Division (OR-OSHA): Portland, OR, January 10, 2005.

OSHA 2005c. Inspection Report for The Gunlocke Company, LLC, Wayland, NY; Inspection number 307690578; U.S. Department of Labor, 

Occupational Safety and Health Administration (OSHA): North Syracuse, NY, September 21, 2005.

OSHA 2006a. Inspection Report for Wood Goods Industries, Inc., Luck, WI; Inspection number 307041707; U.S. Department of Labor, 

Occupational Safety and Health Administration (OSHA): Eau Claire, WI, December 18, 2006.

OSHA 2007a. Inspection Report for The Commercial Furniture Group, Morristown, TN; Inspection number 311144059; State of Tennessee, 

Department of Labor and Workforce Development, Division of Occupational Safety and Health: Nashville, TN, July 9, 2007.

OSHA 2008a. Inspection Report for Benvenuti and Stein, Inc., Evanston, IL; Inspection number 312188972; U.S. Department of Labor, 

Occupational Safety and Health Administration (OSHA): Des Plaines, IL, September 26, 2008.

OSHA 2008b. Occupational Safety and Health Standards: Toxic and Hazardous Substances: Formaldehyde; 29 C.F.R. 1910.1048 

(December 12, 2008). http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10075

(accessed September 7, 2011).

OSHA 2008c. Inspection Report for Unilin Flooring NC, LLC, Mt. Gilead, NC; Inspection number 312479835; North Carolina Department of 

Labor, Division of Occupational Safety and Health: Charlotte, NC, July 28, 2008.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page 102

OSHA 2009a. Occupational Safety and Health Administration (OSHA) Integrated Management Information System (IMIS) database for 

formaldehyde (substance codes 1290, 1291, 1293) in all NAICS codes, encompassing the dates 1979 to 2009 (accessed June 

2009).

OSHA 2009b. Inspection Report for Ameriwood Industries, Inc., Tiffin, OH; Inspection number 311606883; U.S. Department of Labor, 

Occupational Safety and Health Administration (OSHA): Toledo, OH, March 23, 2009.

OSHA 2010a. OSHA targets high hazard worksites for inspection. OSHA QuickTakes [Online] 2010, 9 (19). 

http://www.osha.gov/as/opa/quicktakes/qt10012010.html (accessed September 29, 2011).

OSHA 2010b. Chemical Sampling Information: Formaldehyde [Online]; Occupational Safety and Health Administration (OSHA): 2010. 

http://www.osha.gov/dts/chemicalsampling/data/CH_242600.html.

Preuss et al. 1985a. Preuss, P.W.; Dailey, R.L.; Lehman, E.S. Exposure to formaldehyde. In Formaldehyde. Analytical Chemistry and 

Toxicology; Turoski, V., Ed.; Advances in Chemistry Series, Vol. 210; American Chemical Society: Washington, DC, 1985; 

pp 247-259.

Reinke 2009a. Reinke, Patricia H.; Keil, Charles B. Well-Mixed Box Model. In Mathematical Models for Estimating Occupational Exposure 

to Chemicals, 2nd ed.; Keil, Charles B.; Simmons, Catherine E.; Anthony, T. Renée, Eds.; American Industrial Hygiene 

Association: Fairfax, VA, 2009; pp 23-31.

RIOPA 2005a. Weisel, Clifford P.; Zhang, Junfeng (Jim); Turpin, Barbara J.; Morandi, Maria T.; Colome, Steven; Stock, Thomas H.; 

Spektor, Dalia M.; and Others. Relationships of Indoor, Outdoor, and Personal Air (RIOPA): Part I. Collective Methods and 

Descriptive Analyses; Number 130 Part I; Research Report for the Health Effects Institute (HEI): November 2005.

Tohmura 2000a. Tohmura, Shin-ichiro; Hse, Chung-Yun; Higuchi, Mitsuo. Formaldehyde emission and high-temperature stability of cured 

urea-formaldehyde resins. J. Wood Sci. 2000, 46, 303-309.

USDA 1996a. Ince, Peter J. Recycling of Wood and Paper Products in the United States; FPL-GTR-89; U.S. Department of Agriculture 

(USDA), Forest Service, Forest Products Laboratory: Madison, WI, 1996.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page 103

USEPA 1991a. Chemical Engineering Branch Manual for the Preparation of Engineering Assessments, Volume 1; U.S. Environmental 

Protection Agency (USEPA), Office of Pollution Prevention and Toxics, Chemical Engineering Branch: Washington, DC, 

February 1991.

USEPA 1996a. Turner, Sonji; Martin, Cybele; Hetes, Robert; Northeim, Coleen. Sources and Factors Affecting Indoor Emissions from 

Engineered Wood Products: Summary and Evaluation of Current Literature; EPA-600-R-96-067; U.S. Environmental 

Protection Agency (USEPA), National Risk Management Research Laboratory: Research Triangle Park, NC, June 1996.

USEPA 1997a. Exposures Factors Handbook; EPA/600/P-95/002; U.S. Environmental Protection Agency (USEPA), Office of Research and 

Development, National Center for Environmental Assessment: Washington, DC, August 1997.

USEPA 2000a. Case Studies: Low-VOC / HAP Wood Furniture Coatings; EPA-600/R-00-043; U.S. Environmental Protection Agency

(USEPA), National Risk Management Research Laboratory: Research Triangle Park, NC, May 2000.

USEPA 2000b. Options for Revising CEB’s Method for Screening-Level Estimates of Dermal Exposure – Final Report; U.S. Environmental 

Protection Agency (USEPA), Office of Pollution Prevention and Toxics, Chemical Engineering Branch: Washington, DC, 

June 2000.

USEPA 2009a. Risk Assessment Guidance for Superfund Volume I: Human Health Evaluation Manual (Part F, Supplemental Guidance for 

Inhalation Risk Assessment); U.S. Environmental Protection Agency (USEPA): January 2009.

USEPA 2009b. Formaldehyde from Pressed Wood Products: Exposure Assessment – Draft Final Report; U.S. Environmental Protection 

Agency (USEPA), Office of Pollution Prevention and Toxics, Exposure Assessment Branch: Washington, DC, December 

2009.

USEPA 2010a. Market Profile for Industries Potentially Affected by the Proposed Formaldehyde Standards for Composite Wood Products 

Rule – Internal Deliberative; U.S. Environmental Protection Agency (USEPA), Office of Pollution Prevention and Toxics, 

Economic and Policy Analysis Branch: Washington, DC, December 2010.

USEPA 2010b. Municipal Solid Waste in The United States: 2009 Facts and Figures; EPA530-R-10-012; U.S. Environmental Protection 

Agency (USEPA), Office of Solid Waste: Washington, DC, December 2010.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page 104

USEPA 2011a. Draft Final Occupational and Consumer Exposure and Environmental Release Assessment of Formaldehyde in UreaFormaldehyde Resin Manufacture and of Certain Chemicals for Substitute Technologies to Reduce Emissions from Composite 

Wood Products; U.S. Environmental Protection Agency (USEPA), Office of Pollution Prevention and Toxics, Chemical 

Engineering Branch and Exposure Assessment Branch: Washington, DC, October 2011.

USEPA 2011b. An Introduction to Indoor Air Quality (IAQ): Formaldehyde [Online]; U.S. Environmental Protection Agency (USEPA), 

Updated February 15, 2011. http://www.epa.gov/iaq/formalde.html.

USEPA 2011c. Construction and Demolition Materials; U.S. Environmental Protection Agency (USEPA), Updated July 27, 2011. 

http://www.epa.gov/wastes/nonhaz/industrial/cd/index.htm.

USITC 2008a. Wood Flooring and Hardwood Plywood: Competitive Conditions Affecting the U.S. Industries; USITC Publication 4032; U.S. 

International Trade Commission (USITC), Washington, DC, August 2008.

Walpole 2002a. Walpole, Ronald E.; Myers, Raymond H.; Myers, Sharon L.; Ye, Keying. Probability and Statistics for Engineers and 

Scientists, 7th ed.; Prentice Hall: Upper Saddle River, NJ, 2002; pp 234-236.

Wong 2006. Wong, L.T.; Mui, K.W.; Hui, P.S.A statistical model for characterizing common air pollutants in air-conditioned offices. 

Atmospheric Environment 2006, 40, 4246-4257.

WorksafeBC 2009a. Occupational Exposure Limits for Formaldehyde; Formaldehyde OEL Study, Policy and Research Division, 

WorksafeBC: Vancouver, BC, July 2009.

Zinn 1990a. Zinn, Terry W.; Cline, Dennis; Lehmann, William F. Long-term study of formaldehyde emission decay from particleboard. 

Forest Prod. J. 1990, 40 (6), 15-18.
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Appendix A

DEFINITION OF TERMS
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Page A-1

Definition of Terms

American Conference of 

Governmental Industrial 

Hygienists (ACGIH)

ACGIH is a member-based organization of industrial 

hygienists whose goal is to advance occupational and 

environmental health. ACGIH performs individual lab tests 

and develops with their own exposure limits that are 

sometimes used as suggested standards.

Action Level Action level means a concentration designated in 29 CFR 

1910 for a specific substance, calculated as an 8-hour timeweighted average (TWA), which initiates certain required 

activities such as exposure monitoring and medical 

surveillance.

CARB Compliant Products In 2008, the California Air Resources Board (CARB) issued 

an airborne toxic control measure (ATCM) for three 

composite wood products. The emission standards were 

issued in two phases. Products that are manufactured in 

accordance with emissions standards issued under Phase 1 

and Phase 2 of the CARB rule are referred to as CARB 

Phase 1 compliant and CARB Phase 2 compliant products, 

respectively. Products that do not meet the standards set by 

CARB are herein referred to as non-CARB compliant

products. Table C-2 in Appendix C summarizes the CARB 

emission standards.

Ceiling Limit (C) The air concentration for a substance that should not be 

exceeded during any part of the occupational exposure.

Composite Wood Products 

(CWPs)

The manufacture of most composite wood products involves 

an operation where the wood material is bonded with a 

resin. In this report, composite wood products refer 

specifically to hardwood plywood, medium-density

fiberboard, and particleboard.

Composite Wood Product 

Fabrication

The manufacture of commercial or consumer products, such 

as cabinets and furniture, from HWPW, MDF, and PB.

Emission Level A term used to indicate concentration of formaldehyde in a 

test chamber for a CWP. In this report, emission levels are 

assumed to be measured using the ASTM E1333 large 

chamber test method.
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Emission Rate A term that is used in this document to describe the 

emissions of formaldehyde as a flux, meaning a quantity

(such as mass) of formaldehyde emitted per unit emitting 

area and per unit time. Concentrations measured using 

ASTM E1333 may be used to calculate emission rates (in 

units of flux) according to the method described in ASTM 

E1333 (see Appendix E). Emission rates are alternatively

referred to as emission factors (see the BIFMA M7.1-2007 

method).

Exposure Contact with a substance by inhalation, dermal contact, or 

ingestion.

The magnitude of exposure is a measure of the 

concentration of a substance contacted over a period of 

time. 

Exposure Assessment The process of determining how people come into contact 

with a hazardous substance, how often and for how long 

they are in contact with the substance, and how much of the 

substance they are in contact with.

Exposure Pathway The route a substance takes from its source (where it began) 

to its end point (where it ends), and how people can come 

into contact with (or get exposed to) it. An exposure 

pathway has five parts: a source of contamination (such as a 

composite wood product); an environmental media and 

transport mechanism (such as the off-gassing of 

formaldehyde through air); a point of exposure (such as an 

individual’s breathing zone); a route of exposure 

(inhalation), and a receptor population (people potentially or 

actually exposed). When all five parts are present, the 

exposure pathway is termed a completed exposure pathway.
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Hardwood Plywood (HWPW) According to FSCWPA, a hardwood or decorative panel 

that is:

i. intended for interior use; and

ii. composed of (as determined under the

standard numbered ANSI/HPVA HP–1–2009) an

assembly of layers or plies of veneer, joined by an

adhesive with:

I. lumber core;

II. particleboard core;

III. medium-density fiberboard core;

IV. hardboard core; or

V. any other special core or special back 

material.

This does not include:

i. military-specified plywood;

ii. curved plywood; or

iii. any other product specified in—

I. the standard entitled ‘Voluntary Product

Standard—Structural Plywood’ and 

numbered PS1–07; or

II. the standard entitled ‘Voluntary Product

Standard—Performance Standard for WoodBased Structural-Use Panels’ and numbered 

PS 2–04.

Note that the definition of hardwood plywood includes 

engineered veneer and any laminated product unless EPA 

exempts them by rule-making.

Laminated Product According to FSCWPA, a product:

(I) in which a wood veneer is affixed to:

(aa) a particleboard platform;

(bb) a medium-density fiberboard platform; or

(cc) a veneer-core platform; and

(II) that is:

(aa) a component part;

(bb) used in the construction or assembly of a finished 

good; and

(cc) produced by the manufacturer or fabricator of the 

finished good in which the product is incorporated.

EPA has the discretion to change this definition.
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Life Cycle All stages of a product’s development, from manufacture 

and processing to distribution, use, and disposal and 

recycling.

Manufacturing The manufacture of the composite wood products: HWPW, 

MDF, and PB. May also be referred to as “primary

manufacturing”.

Medium-Density Fiberboard 

(MDF)

According to FSCWPA, a panel composed of cellulosic 

fibers made by dry forming and pressing a resinated fiber 

mat (as determined under the standard numbered ANSI

A208.2–2009).

No Added Formaldehyde (NAF) 

Resins

According to FSCWPA: 

(A) IN GENERAL:

(i) a resin formulated with no added formaldehyde as part 

of the resin cross-linking structure in a composite wood 

product that meets the emission standards in subparagraph 

(C) as measured by: one test conducted pursuant to test 

method ASTM E–1333–96 (2002) or, subject to clause 

(ii), ASTM D–6007–02; and 3 months of routine quality

control tests pursuant to ASTM D–6007–02 or ASTM D–

5582 or such other routine quality control test methods as 

may be established by the Administrator through 

rulemaking.

(ii) Test results obtained under clause (i)(I) or (II) by any 

test method other than ASTM E–1333–96 (2002) must 

include a showing of equivalence by means established by

the Administrator through rulemaking.

(B) INCLUSIONS: The term ‘no-added formaldehyde 

based resin’ may include any resin made from:

(i) soy;

(ii) polyvinyl acetate; or

(iii) methylene diisocyanate.

(C) EMISSION STANDARDS: The following are the 

emission standards for composite wood products made with 

no-added formaldehyde-based resins under this paragraph:

(i) No higher than 0.04 parts per million of formaldehyde 

for 90 percent of the 3 months of routine quality control 

testing data required under subparagraph (A)(ii).

(ii) No test result higher than 0.05 parts per million of 

formaldehyde for hardwood plywood and 0.06 parts per 

million for particleboard, medium-density fiberboard, and 

thin medium-density fiberboard.
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National Institute for 

Occupational Safety and Health 

(NIOSH)

As part of the Centers for Disease Control, NIOSH is 

responsible for conducting research and making 

recommendations for the prevention of work-related 

illnesses and injuries. 

Occupational Exposure Contact with a substance as a result of one’s work 

environment. 

Occupational Safety and Health 

Administration (OSHA)

OSHA is the main federal agency charged with the 

enforcement of safety and health legislation. OSHA has the 

regulatory authority to set exposure limits for specific 

chemicals or groups of chemicals.

OSHA Integrated Management 

Information System (IMIS)

IMIS is an on-line data entry and information retrieval 

system designed to collect, process, retrieve, and 

communicate penalty assessment, arbitration, and collection 

information regarding OSHA's inspections.

OSHA Inspection Type: 

FAT-CAT

Complaint

OSHA inspections following a fatality or catastrophe at a 

facility.

OSHA inspections resulting from worker complaints of 

unsafe or unhealthful working conditions. 

Follow-Up A follow-up inspection determines if the employer has 

corrected previously cited violations. If the employer fails to 

abate a former violation, he or she is subject to additional 

penalties until the violation is corrected. 

Planned

Programmed

Related

The inspection was planned based on a particular reason, 

which can vary. An example reason may include OSHA 

determining that a certain industry has a particular hazard 

more than others, so a random sample of facilities within 

that industry is selected for inspection. 

Planned and/or programmed inspections aimed at specific 

high-hazard industries, workplaces, occupations, health 

substances, or other industries identified in OSHA’s current 

inspection procedures. 

The inspection was conducted due to concern over the 

facility regarding a different category, and upon 

investigation, OSHA determined that a related hazard 

should be monitored. 
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Referral

Unprogrammed

OSHA inspections resulting from referrals. Referrals may

come from any source including but not limited to: state 

EPA, health department, fire department, building code 

inspectors, newspaper, and related OSHA inspections. 

The facility was not inspected based on any planned or 

programmed list of industries or facilities. These are the 

most random of OSHA inspections. 

Particleboard (PB) According to FSCWPA, a panel composed of cellulosic 

material in the form of discrete particles (as distinguished 

from fibers, flakes, or strands) that are pressed together with 

resin (as determined under the standard numbered ANSI

A208.1–2009)

This does not include any product specified in the standard 

entitled ‘Voluntary Product Standard—Performance

Standard for Wood-Based Structural-Use Panels’ and

numbered PS 2–04.

Peak Concentration The maximum air concentration of a chemical that is 

observed for a given sampling event. 

Permissible Exposure Limit 

(PEL)

PELs are regulatory limits issued by OSHA for the amount 

or concentration of a substance in the air. They may also 

contain a skin designation. OSHA PELs are based on an 8-

hour time weighted average (TWA) exposure.

Potential Dose The amount of a substance that is taken in by the body 

through ingestion, inhalation or dermal contact. In this 

report, the potential dose, also referred to as “dose” applies 

to the amount of the substance that is inhaled.

Recommended Exposure Limit 

(REL)

Unless noted otherwise, RELs are time-weighted average 

(TWA) concentrations for up to a 10-hour workday during a 

40-hour workweek. Unlike PELs, which are regulatory

limits, RELs are recommended limits issued by NIOSH.
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Short-Term Exposure Limit 

(STEL)

A STEL is defined as a 15-minute TWA exposure that 

should not be exceeded at any time during the work day

even if the 8-hr TWA is within established limits. An 

averaging period other than 15 minutes may be used when 

this is warranted by observed biological effects.

The American Conference of Governmental Industrial 

Hygienists (ACGIH) recommends that exposures beyond 

the time-weighted average limit (whether regulatory or 

otherwise) up to the STEL should not occur more than 4 

times per day with at least 60 minutes between successive 

exposures in this range.

Threshold Limit Value (TLV) TLVs are recommended exposure limits that are issued by

the ACGIH. TLVs are airborne concentrations of substances 

to which it is believed that nearly all workers may be 

repeatedly exposed day after day without adverse effect. 

There are three categories of TLVs: TLV-TWA; TLVSTEL; and TLV-C.

Time-Weighted Average (TWA) 

Concentration

Average air concentration of a substance based on a normal 

8-hour work day and a 40-hour work week. OSHA PELs are 

based on an 8-hour time-weighted average (TWA) 

exposure.
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Ultra Low-Emitting 

Formaldehyde (ULEF) Resin

According to FSCWPA:

(A) IN GENERAL:

(i) The term ‘ultra low-emitting formaldehyde resin’ 

means a resin in a composite wood product that meets the 

emission standards in subparagraph (C) as measured by:

(I) 2 quarterly tests conducted pursuant to test method 

ASTM E–1333–96 (2002) or, subject to clause (ii), 

ASTM D–6007–02; and

(II) 6 months of routine quality control tests pursuant to 

ASTM D–6007–02 or ASTM D–5582 or such other 

routine quality control test methods as may be

established by the Administrator through rulemaking.

(ii) Test results obtained under clause (i)(I) or (II) by any 

test method other than ASTM E–1333–96 (2002) must 

include a showing of equivalence by means established by

the Administrator through rulemaking.

(B) INCLUSIONS: The term ‘ultra low-emitting

formaldehyde resin’ may include:

(i) melamine-urea-formaldehyde resin;

(ii) phenol formaldehyde resin; and

(iii) resorcinol formaldehyde resin.

(C) EMISSION STANDARDS:

(i) The Administrator may, pursuant to regulations

issued under subsection (d), reduce the testing requirements 

for a manufacturer only if its product made with ultra lowemitting formaldehyde resin meets the following emission 

standards:

(I) For hardwood plywood, no higher than 0.05 parts per 

million of formaldehyde.

(II) For medium-density fiberboard:

(aa) no higher than 0.06 parts per million of 

formaldehyde for 90 percent of 6 months of routine 

quality control testing data required under 

subparagraph (A)(ii); and

(bb) no test result higher than 0.09 parts per million of 

formaldehyde.
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(III) For particleboard:

(aa) no higher than 0.05 parts per million of 

formaldehyde for 90 percent of 6 months of routine 

quality control testing data required under 

subparagraph (A)(ii); and

(bb) no test result higher than 0.08 parts per million of 

formaldehyde.

(IV) For thin medium-density fiberboard:

(aa) no higher than 0.08 parts per million of 

formaldehyde for 90 percent of 6 months of routine 

quality control testing data required under 

subparagraph (A)(ii); and

(bb) no test result higher than 0.11 parts per million of 

formaldehyde.

(ii) The Administrator may not, pursuant to regulations

issued under subsection (d), exempt a manufacturer from 

third party certification requirements unless its product 

made with ultra low-emitting formaldehyde resin meets 

the following emission standards:

(I) No higher than 0.04 parts per million of

formaldehyde for 90 percent of 6 months of routine

quality control testing data required under subparagraph 

(A)(ii).

(II) No test result higher than 0.05 parts per million of 

formaldehyde for hardwood plywood and 0.06 parts per 

million for particleboard, medium-density fiberboard, 

and thin medium-density fiberboard.
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Appendix B

DATA QUALITY ACCEPTANCE CRITERIA SPECIFICATIONS
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Data Quality Acceptance Criteria Specifications

Specifications for Data Elements

Acceptance 

Criterion: 

Description/Definition Specification

Currency Is the information up to date? Does 

it reflect current conditions?

Process Description: Year of source is 1990 or 

after

Number of Sites and Production Data: Year of 

source is 2000 or after and correlates with 

number of sites

Exposure Data: 

Priority - Year of source is 2004 or after1

Consider - Year of source is 1999 or after

Geographic Scope Does the information reported reflect 

an area relevant to the assessment?

All Data: 

Priority – sources describing U.S. sites

When U.S. data are not available, consider 

sources from countries with geographic 

proximity that may adopt similar processes or 

from other developed countries that may have 

similar regulations and standards. 

Process Description:

Consider – sources describing Canadian, 

Mexican, or European processes. 

Number of Sites and Production Data: 

Consider – North American sites (and 

interpolate to estimate U.S. sites and production)

Exposure Data: 

Consider – Canadian or European data. 

Accuracy/Reliability Is the information or data from a 

peer-reviewed, government, or 

industry-specific source? Is the 

source published? Is the author 

engaged in a relevant field such that 

competent knowledge is expected 

(i.e., the author writes for an industry 

trade association publication versus a 

general newspaper)? 

All Data: 

U.S. or other government publication

For an academic researcher:

 Publication in peer-reviewed journal 

 Presentation at a technical conference

 Source has documented qualifications/ 

credentials to discuss particular topic 

For an industry expert or trade group: 

 Presentation at a technical conference 

where the information is subject to 

review by other industry experts

 Source has documented qualifications/ 

credentials to discuss particular topic 

 Source represents a large portion of the 

industry of interest
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Acceptance 

Criterion: 

Description/Definition Specification

Unbiased2Is the information objective towards 

a particular product or outcome?

All Data:

 Objective of the information is clear.

 Methodology is designed to answer a 

specific question.

Comparability Are the data comparable to other 

sources that have been identified or 

are they significantly different than 

other sources?

Production Data, Exposure Data, and Number of 

Sites: Values are within the same order of 

magnitude of each other. 

Process Description: Matches or is similar to 

other information for the same industry and will 

be evaluated on a case-by-case basis.

Representativeness Do the data reflect typical industry 

practices? 

All Data: 

Information is relevant to the industry and from 

a reputable source with qualifications in the 

industry of interest.

Data are based on a large industry survey or 

study, as opposed to a case study or sample from 

a limited number of sites. 

Applicability For surrogate data, are the data 

expected to be similar for the 

industry of interest? 

Surrogate data used to fill data gaps must be 

judged to be similar to the data of interest: 

 Industry is similar in size 

 Same types of chemicals are used

 Similar processes and activities are 

performed

 Similar levels of engineering controls 

and personal protective equipment are 

used

1 EPA promulgated in 2004 the Plywood and Composite Wood Products MACT Rule for hazardous air pollutants 

(HAPs), including formaldehyde, for regulated units. 

2

Information from advocacy groups should be collected and judged for acceptability. While such information may 

be biased, it may provide references to other useful sources.
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Appendix C

EXISTING FORMALDEHYDE OCCUPATIONAL EXPOSURE LIMITS AND 

FORMALDEHYDE OFF-GASSING EMISSION STANDARDS FOR COMPOSITE 

WOOD PRODUCTS
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Formaldehyde Occupational Exposure Limits

The Occupational Safety and Health Administration (OSHA) sets permissible exposure limits 

(PELs) to regulate worker exposure to formaldehyde in occupational settings. OSHA has 

established two types of exposure limits for airborne exposures to formaldehyde: a 0.75 parts per 

million (ppm) time-weighted average (TWA) PEL over an 8-hour period and a 2 ppm short-term 

exposure limit (STEL) over a 15-minute period.

Table C-1 summarizes these OSHA exposure limits as well as other formaldehyde exposure 

limits for the U.S. and for other countries.

Table C-1. Existing Occupational Exposure Limits for Formaldehyde

Country Concentration (ppm) Type

USA-ACGIH 0.3 Ceiling

USA-NIOSH 0.016 TWA

USA-OSHAb0.75 TWA

USA-OSHA 2.0 STEL

Canada-Alberta 2.0 Ceiling

Canada-Ontario 0.3 Ceiling

Canada-Quebec 2.0 Ceiling

Sweden 0.5 TWA

New Zealand 1.0 Ceiling

Australia a1.0 TWA

Japan 0.5 TWA

United Kingdom 2.0 TWA

a – Australia proposed a lower occupational exposure limit of 0.3 ppm in 2008 (Chimar Hellas undated).

b – The OSHA action level for formaldehyde is 0.5 ppm TWA (29 CFR § 1910.1048).

Sources: IARC 2006a, Chimar Hellas undated, and OSHA 2010b

Formaldehyde Emission Standards for Composite Wood Products

Emission standards have been established in the U.S. for HWPW, MDF, and PB. The American 

National Standards Institute (ANSI) established a voluntary standard for MDF and PB, while the 

Department of Housing and Urban Development (HUD) established national standards for 

plywood and particleboard (CARB 2007a). In 2008, CARB issued an air toxics control measure 

(ATCM) for the state of California, which provided stricter formaldehyde emission standards 

than the existing national standards (see Table C-2). The ANSI standards have been revised to 

reflect the CARB ATCM emission standards.

The CARB regulation focuses only on three types of composite wood products: HWPW, PB, and 

MDF. CARB set emission standards for each of these products based on best achievable control 

technologies (BACTs). The BACTs were selected based on CARB survey results, information 

in the open literature, and expert judgment on low- and no-added formaldehyde resin 
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technologies. The selected BACTs are such that the three regulated products have different 

emission standards (CARB 2007a).

CARB reported the resin types used by the manufacturers who responded to the CARB 2003 

survey (CARB 2007a).

 Of the HWPW manufacturer responses, which accounted for 73% of domestic 

HWPW production:

o All companies reported using ammonia-UF resin. The lowest emission 

rates were achieved with the use of catalysts, such as ammonium chloride 

or hexamethylenetetramine.

 Of the PB manufacturer responses, which accounted for 53% of domestic PB 

production:

o 51% of the reported production volume used a straight polymer UF resin;

o 48% of the reported production volume used a methanol-UF resin; and

o 1% of the reported production volume used a blended PF-UF resin.

 Of the MDF manufacturer responses, which represented 83% of domestic MDF 

production:

o 40% of the reported production volume used a straight polymer UF resin;

o 20% of the reported production volume used a methanol-UF resin;

o 39% of the reported production volume used a melamine-UF resin with 

sodium chloride catalyst; and

o 1% of the reported production volume used MDI resin.

The majority of the reported resins used were UF resins with many using additives, such as 

ammonia or methanol, and catalysts.
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Table C-2. California Phase 1 and Phase 2 Formaldehyde Emission Standards

ASTM E1333 Standard Concentrations (ppm) a

Phase 1 Formaldehyde Emission Standards

Effective 

Date

HWPW-VC b HWPW-CC c PB MDF tMDF d

Jan 2009 0.08 — 0.18 0.21 0.21

July 2009 — 0.08 — — —

Phase 2 Formaldehyde Emission Standards

Effective 

Date

HWPW-VC b HWPW-CC c PB MDF tMDF d

Jan 2011 0.05 — 0.09 0.11 —

Jan 2012 — — — — 0.13

July 2012 — 0.05 — — —

a – ppm = parts per million. In this case, parts of formaldehyde per million parts of air.

b – HWPW-VC = hardwood plywood – veneer core.

c – HWPW-CC = hardwood plywood – composite core. 

d – tMDF = thin medium-density fiberboard (8-mm or thinner).

Source: CARB 2007a
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Table C-3. Formaldehyde Emission Limits and Corresponding Emission Rates as Measured using ASTM E1333 under HUD, CARB, 

and FSCWPA

HUD, CARB, and FSCWPA Limits as 

Measured from ASTM E1333

ASTM E1333 Test 

Parameters Calculated Values (see Appendix E)

Concentration 

(ppm)

Concentration 

(mg/m3)

Loading 

Ratio 

(m2/m3)

Air 

Change 

Rate (hr-1)

Formaldehyde 

Emission Rate

(mg/m2-hr)

Area-Specific 

Airflow Rate 

(m3/m2-hr)

HWPW

HUD 0.2 0.246 0.43 0.5 0.2858 1.16

CARB Phase 1 0.08 0.098 0.43 0.5 0.1143 1.16

FSCWPA / CARB Phase 2 0.05 0.061 0.43 0.5 0.0715 1.16

ULEF 0.045 0.0553 0.43 0.5 0.0643 1.16

NAF 0.04 0.0492 0.43 0.5 0.0572 1.16

PB

HUD 0.3 0.369 0.43 0.5 0.4287 1.16

CARB Phase 1 0.18 0.221 0.43 0.5 0.2572 1.16

FSCWPA / CARB Phase 2 0.09 0.111 0.43 0.5 0.1286 1.16

ULEF 0.045 0.055 0.43 0.5 0.0643 1.16

NAF 0.04 0.049 0.43 0.5 0.0572 1.16

MDF

HUD None -- -- -- -- --

CARB Phase 1 0.21 0.258 0.26 0.5 0.4963 1.92

FSCWPA / CARB Phase 2 0.11 0.135 0.26 0.5 0.2600 1.92

ULEF 0.05 0.061 0.26 0.5 0.1182 1.92

NAF 0.04 0.049 0.26 0.5 0.0945 1.92
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Appendix D

FORMALDEHYDE CWP OFF-GASSING EMISSION LEVEL DATA FOR THE PREBASELINE PERIOD, BASELINE, AND THE ANALYTICAL OPTIONS
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Use of Emission Levels in the Assessment of Formaldehyde Occupational Exposure

Emission levels for formaldehyde off-gassing from CWP, which have units of concentration, are 

converted to emission rates, which have units of flux, and are used in the mass balance equations 

used to calculate indoor air concentrations due to off-gassing of CWPs in fabrication sites and in 

office buildings for the baseline and the three analytical options. Pre-baseline emission levels 

are used to calculate pre-baseline indoor air concentrations in CWP fabrication sites for the 

purpose of comparing model results to pre-baseline OSHA IMIS data as described in Section 

4.2.5.3. Pre-baseline emission levels are also used to estimate the barrier effectiveness of the 

finishing (coating, overlays, etc) of the CWP from which office building workstation 

components are fabricated. This barrier effectiveness is used in the calculation of formaldehyde 

indoor air concentration in office buildings for the baseline and the three analytical options (see 

Section 3.3.1.2 and Appendix E).

Emission Levels of Pre-Baseline CWPs

This section discusses the available pre-baseline emission level data and the estimation of prebaseline emission levels. The pre-baseline emission levels used in this assessment are 

summarized in Table D-1 below. The data used to estimate these emission levels are presented 

in Table D-2.

Considerable information is available on the emission levels of domestically-produced prebaseline products as shown in Table D-2. As seen in this table, at the beginning of the prebaseline period of 2002 to 2009, the production-weighted average emission levels of 

domestically-produced CWP were close to the CARB ATCM Phase 1 limits while the range of 

emission levels for these products had a lower bound that was less than the CARB ATCM Phase 

1 standard emission level, and an upper bound that was considerably greater. In ANPR 

submissions, it is noted that 75% of HWPW and 96% of PB and MDF met the CARB ATCM 

Phase 1 limit by 2009. Therefore, the CARB ATCM Phase 1 limits were assumed to be 

representative of average pre-baseline emission levels for CWP produced domestically during 

the pre-baseline period of 2002 to 2009, and the average emission levels for domesticallyproduced HWPW, PB, and MDF were equated to the CARB ATCM Phase 1 limits (0.08 ppm, 

0.18 ppm, and 0.21 ppm, respectively).

Emission levels of imported pre-baseline CWPs are not available and were estimated taking into 

account temporal trends in the emission levels of domestically-produced CWP and the reported 

emission levels of imported CWP. The emission levels of baseline products (domestically

produced and imported) and their share of U.S. consumption is provided in the market profile

(USEPA 2010a) in Table 12-5. A comparison of Table D-2 and Table 12-5 in the market profile 

(reproduced as Table D-3 in this appendix) shows that a considerable decrease in the emission 

levels of domestically-produced CWP will occur in going from the pre-baseline period to the 

baseline. This temporal trend was assumed to apply to imported CWP such that there would be a 

decline in the emission levels of imported CWP from the pre-baseline period to the baseline. 

The pre-baseline emission levels for Canadian imported CWP and non-Canadian imported CWP 

were estimated differently as discussed below.
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According to Table 12-5 in the market profile (USEPA 2010a), baseline CWP imported from 

Canada have emission levels that are identical to the emission levels of domestically-produced 

baseline CWP. This similarity was assumed to extend to the pre-baseline period, and therefore 

CWP imported from Canada during the pre-baseline period were assumed to have emission 

levels that are identical to the values assumed for domestically produced pre-baseline CWP.

Most of the non-Canadian imported CWP will adhere to the CARB Phase 2, ULEF, or NAF 

standards at baseline, but will have emission level values that are different from those of U.S. 

and Canadian CWP. The baseline emission levels of non-Canadian imports are likely not 

representative of pre-baseline emission levels of these imports assuming that there will be a 

decline in emission levels of imported CWP from the pre-baseline to baseline as discussed 

above. The fraction of imported baseline CWP that will not adhere to any of the CARB emission 

standards will be approximately 26%, 37%, and 10% for HWPW, PB, and MDF, respectively. 

The average values of the emission levels for these volumes will be 0.163 ppm, 0.384 ppm, and 

0.502 ppm for HWPW, PB, and MDF, respectively, as shown in Table D-2. It is assumed that 

these emission levels are representative of the average pre-baseline emission levels for each 

CWP type for imported CWP.

In conclusion, the average emission levels for domestic and Canadian pre-baseline HWPW, PB, 

and MDF are assumed to be equal to the CARB ATCM Phase 1 limits (0.08 ppm, 0.18 ppm, and 

0.21 ppm, respectively). The average emission levels for imported pre-baseline HWPW, PB, and 

MDF are assumed to be equal to 0.163 ppm, 0.384 ppm, and 0.502 ppm, respectively.

An average emission level for all three CWP was used in the estimation of barrier effectiveness

for use in the calculation of office building indoor air concentration. Therefore, these emission 

levels are averaged together. First, a volume-weighted average of the emission levels of 

domestically-produced and imported CWP is calculated for each individual CWP type. The EPA 

market profile provides the 2005 volume-based shares of domestic consumption of 

domestic/Canadian and imported CWP (Table 12-4 in USEPA 2010a). The volume-based shares 

of domestic consumption of non-Canadian imported CWPs are 64%, 3.5%, and 7.6% for 

HWPW, PB, and MDF, respectively. The shares of domestic/Canadian CWPs are the difference 

between 100% and the import shares. A volume-weighted average emission level is calculated 

for each CWP type as follows. The emission rates (in units of flux) are similarly calculated.

For HWPW:

(0.64) × (0.163 ) + (0.36) × (0.08 ) = 0.13 

For PB:

(0.035) × (0.384 ) + (0.965) × (0.18 ) = 0.19 

For MDF:

(0.076) × (0.502 ) + (0.924) × (0.21 ) = 0.23 

Next, a single volume-weighted average emission level for all three CWP types is calculated 

from the three CWP weighted averages calculated above. Table 12-4 in the EPA market profile

(USEPA 2010a) also provides annual consumption volumes of the three CWP for the year 2005. 

Based on these data, the consumption volumes of HWPW, PB, and MDF as a fraction of total the 
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page D-3

total consumption volume for these three CWP was 31.1%, 46.4%, and 22.5%, respectively. The 

single volume-weighted average emission level for all three CWPs is calculated as follows. The 

emission rates (in units of flux) are similarly calculated.

(0.311) × (0.13 ) + (0.464) × (0.19 ) + (0.225) × (0.23 ) = 0.18 

Table D-1. Pre-Baseline Formaldehyde Emission Levels for CWPs used in this Assessment

CWP Type

Domestic or 

Import Units

Average 

Value

VolumeWeighted 

Average Basis

HWPW

Domestics ppm 0.08

0.13

CARB ATCM Phase 1 Limit

Imports ppm 0.163 Baseline imports that do not 

meet any emission standard

PB

Domestics ppm 0.18

0.19

CARB ATCM Phase 1 Limit

Imports ppm 0.384 Baseline imports that do not 

meet any emission standard

MDF

Domestics ppm 0.21

0.23

CARB ATCM Phase 1 Limit

Imports ppm 0.502 Baseline imports that do not 

meet any emission standard

Volume-Weighted Average of the Volume-Weighted 

Averages for the Three CWPs (ppm) 0.18

HWPW Domestics μg/m2

-h 114.3 190.3

Calculated from emission 

level based on ASTM E1333

(see Appendix E)

Imports μg/m2-h 232.9

PB Domestics μg/m2

-h 257.2 267.3 Imports μg/m2

-h 548.8

MDF Domestics μg/m2

-h 496.3 548.9 Imports μg/m2

-h 1,186.5

Volume-Weighted Average of the Volume-Weighted 

Averages for the Three CWPs (μg/m2-h) 306.7
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Page D-4

Table D-2. Data Used to Determine Pre-Baseline Emission Levels for Composite Wood 

Products

Timeline

Information 

Source HWPW a PB b MDF b

Domestic CWPs

2002 CARB survey

Production-Weighted Average

0.09 ppm 0.18 ppm 0.25 ppm

% of U.S. Production Represented in Survey

73% 53% 83%

Range in Survey Responses

0.07 to 0.75 ppm 0.13 to 0.24 ppm 0.03 to 0.31 ppm

End of 2008 / 

Beginning of 

2009

ANPR 

Submissions

75% of domestically-produced 

CWP were CARB Phase 1 

compliant

96% of 

domesticallyproduced CWP 

were CARB P1 

compliant

96% of 

domesticallyproduced CWP

were CARB P1 

compliant

Later in 2009 ANPR 

Submissions

90% of domestics expected to 

be CARB P1 compliant -- --

Average Emission Levels for Imported Baseline CWPs That Do Not Meet Any of the CARB Emission

Standards (USEPA 2010a)

c

Baseline EPA market 

profile 0.163 ppm 0.384 ppm 0.502 ppm

a – A submission from HPVA in May 2008 estimated that domestically-produced HWPW will be in compliance 

with CARB Phase 1. Phase 2 limits require new technologies, which have not been in commercial use and some 

only recently invented and patented. Additionally, a submission from HPVA in February 2009 estimated that 

75% of North American HWPW was CARB certified and soon 90% or more will be CARB certified. “CARB 

certified” is assumed to mean CARB Phase 1 per the statements made in the May 2008 submission. The term 

“soon” is uncertain; therefore, the point in time in which 90% of domestics were expected to meet CARB Phase 

1 is uncertain.

b – A submission from CPA in May 2008 stated that “almost all” domestic production is expected to be 

compliant with CARB Phase 1 and 2. The volume related to “almost all” is uncertain. This submission also states 

that “eventually” this rate of compliance would be reached; the time frame associated with “eventually” is 

uncertain. CPA did estimate that 96% of domestics were Phase 1 compliant by the end of 2008.

c – Average emission levels of imported CWPs at baseline that do not meet any of the CARB emission standards 

are used as estimates of the average emission levels of all imported CWPs during pre-baseline.

Emission Levels of Baseline CWP and CWP that Would be Produced Under the Analytical

Options

The EPA market profile provides emission levels for CWPs at baseline. These emission levels 

and their corresponding volume-based shares of U.S. consumption are summarized in Table D-3

below. Emission levels and their corresponding volume-based shares of U.S. consumption for 

the analytical options were determined based on the baseline values and are given in Table D-4

through Table D-6 (USEPA 2009b).
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Page D-5

Table D-3. Baseline Emission Levels and Corresponding U.S. Consumption (Copy of Table 

12-5 in Market Profile)

Emission 

Standard

Hardwood Plywood MDF Particleboard

U.S./Can.

NonU.S./Can. U.S./Can.NonU.S./Can. U.S./Can.NonU.S./Can.

Average Emissions (ppm)

None 0.058 0.163 - 0.502 0.058 0.384

CARB P1 - - - - 0.090 -

CARB P2 0.032 0.015 0.082 0.047 0.057 0.036

ULEF - - 0.024 - 0.042 -

NAF 0.013 - 0.035 - 0.013 -

Share of U.S. Consumption

None 0.1% 16.6% - 0.8% 0.2% 1.1%

CARB P1 - - - - 1.7% -

CARB P2 19.7% 47.4% 79.2% 7.2% 85.0% 1.9%

ULEF - - 4.2% - 3.0% -

NAF 16.2% - 8.6% - 7.1% -

Weighted Average Emission Levels (ppm)

National 

Average 0.043 0.076 0.057
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Table D-4. Emission Levels and Corresponding U.S. Share of Consumption for Analytical

Option 1 (CARB Phase 1)

Emission 

Standard

Hardwood Plywood MDF Particleboard

U.S./Can.

NonU.S./Can. U.S./Can.NonU.S./Can. U.S./Can.NonU.S./Can.

Average Emissions (ppm)

None - - - - - -

CARB P1 

(previously 

NOT CARB 

P1)

0.058 a0.058 - 0.14 b0.058 a0.090

Already at

CARB P1 - - - - 0.090 -

CARB P2 0.032 0.015 0.082 0.047 0.057 0.036

ULEF - - 0.024 - 0.042 -

NAF 0.013 - 0.035 - 0.013 -

Share of U.S. Consumption

None - - - - - -

CARB P1 

(previously

NOT CARB 

P1)

0.1% 16.6% - 0.8% 0.2% 1.1%

Already at

CARB P1 - - - - 1.7% -

CARB P2 19.7% 47.4% 79.2% 7.2% 85.0% 1.9%

ULEF - - 4.2% - 3.0% -

NAF 16.2% - 8.6% - 7.1% -

Weighted Average Emission Levels (ppm)

National 

Average 0.025 0.073 0.054

Source: USEPA 2009b

a – This share of consumption was previously given for products not meeting any standard at baseline, but the 

baseline emission level complies with CARB Phase 1 and thus does not change.

b – This emission level is 67% of the CARB Phase 1 limit.
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Table D-5. Emission Levels and Corresponding U.S. Share of Consumption for Analytical

Option 2 (FSCWPA/CARB Phase 2)

Emission 

Standard

Hardwood Plywood MDF Particleboard

U.S./Can.

NonU.S./Can. U.S./Can.NonU.S./Can. U.S./Can.NonU.S./Can.

Average Emissions (ppm)

None - - - - - -

CARB P1 - - - - - -

CARB P2 

(previously not 

CARB P2)

0.032 0.032 - 0.082 0.057 0.057

Already at

CARB P2 0.032 0.015 0.082 0.047 0.057 0.036

ULEF - - 0.024 - 0.042 -

NAF 0.013 - 0.035 - 0.013 -

Share of U.S. Consumption

None - - - - - -

CARB P1 - - - - - -

CARB P2 

(previously not

CARB P2)

0.1% 16.6% - 0.8% 1.9% 1.1%

Already at

CARB P2 19.7% 47.4% 79.2% 7.2% 85.0% 1.9%

ULEF - - 4.2% - 3.0% -

NAF 16.2% - 8.6% - 7.1% -

Weighted Average Emission Levels (ppm)

National 

Average 0.021 0.073 0.053

Source: USEPA 2009b
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Table D-6. Emission Levels and Corresponding U.S. Share of Consumption for Analytical

Option 3 (NAF)

Emission 

Standard

Hardwood Plywood MDF Particleboard

U.S./Can.

NonU.S./Can. U.S./Can.NonU.S./Can. U.S./Can.NonU.S./Can.

Average Emissions (ppm)

None - - - - - -

CARB P1 - - - - - -

CARB P2 - - - - - -

NAF 

(previously not

NAF with nonNAF 

emissions)

a

0.013 0.013 0.035 0.035 0.013 0.013

NAF 

(previously not

NAF with NAF 

emissions)

b

0.024 - -

Already at

NAF 0.013 - 0.035 - 0.013 -

Share of U.S. Consumption

None - - - - - -

CARB P1 - - - - - -

CARB P2 - - - - - -

NAF 

(previously not

NAF with nonNAF 

emissions)

a

19.8% 64.0% 79.2% 8.0% 89.9% 3%

NAF 

(previously not

NAF with NAF 

emissions)

b

4.2% - -

Already at

NAF 16.2% - 8.6% - 7.1% -

Weighted Average Emission Levels (ppm)

National 

Average 0.013 0.035 0.013

Source: USEPA 2009b

a – These shares of consumption were previously given for products not meeting the NAF standard at baseline, and 

the emission levels were changed to match the domestic baseline NAF emission levels.

b - These shares of consumption were previously given for products not meeting the NAF standard at baseline, but 

the baseline emission level complies with NAF and thus does not change.
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Appendix E

MODELING METHODOLOGY FOR ESTIMATING INDOOR AIR

CONCENTRATIONS RELATED TO BASELINE AND ANALYTICAL OPTIONS
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Page E-1

1.0 Indoor Air Concentration Assessment Methods

This section of this appendix describes the modeling methodology for estimating indoor air

concentrations related to baseline and analytical option periods for the three composite wood 

products of interest: HWPW, PB, and MDF. Both inhalation and dermal exposures are assessed.

1.1 CWP Fabrication Indoor Air Concentration Assessment Method

An airborne concentration of a chemical contaminant in a control volume may be determined 

from a mass balance on the chemical as presented in Equation 1 (USEPA 1991a).

 =





Eqn (1)

where:

C = Airborne concentration of the chemical in the work space (μg/m3);

S = Generation rate of the chemical as a vapor or gas from the source of 

interest in the work space (μg/h); and

Q = Volumetric ventilation rate of the work space (m3/h).

The following assumptions apply to this model:

 Extinction of the chemical (adsorption, absorption, or chemical transformation) 

resulting from deposition on walls and equipment, condensation of hot vapors, 

and photodegradation of chemicals is negligible;

 The incoming air is contaminant-free;

 The concentration of contaminant at initial time is negligible (there is no 

background concentration or other generation sources of the contaminant);

 The generation and ventilation rates are constant over time (steady-state 

assumption); and

 Room air and ventilation air mix ideally.

Equation 1 is modified to account for the presence of contaminant in the incoming (outdoor) air. 

A new mass balance is derived to arrive at Equation 2.

 =





+ 

 Eqn (2)

where:

Co

ind

= Concentration of contaminant in the outdoor air (μg/m3).

To account for non-ideal mixing of the ventilation air and the contaminated room air, a 

dimensionless mixing factor, k, is used. One interpretation of the mixing factor is a 

representation of the fraction, k, of the ventilation air that completely mixes with an unknown

fraction of the room volume and the contaminant emitted from the source at the generation rate, 

S. The remaining fraction, 1-k, of the ventilation air only mixes with the remaining (and 
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Page E-2

unknown) fraction of the room volume, which does not mix with the emitted contaminant at 

generation rate, S (Reinke 2009a).

The mixing factor is multiplied by the ventilation rate to approximate an effective ventilation 

rate, which accounts for non-ideal mixing. The effective ventilation rate,  × , is then 

substituted into Equation 2.

 =  ×  Eqn (3)

 =





+ 

 Eqn (4)

Equation 4 is applied to the calculation of the formaldehyde indoor air concentration at a CWP 

fabrication site as follows:

 The entire site constitutes the work space.

 The ideal ventilation rate, Q, is equal to the total ventilation rate of the entire site.

 The mixing factor, k, represents a fraction of the work space volume that 

effectively mixes with a fraction of the ventilation air and the formaldehyde 

emitted at generation rate, S, to result in the average indoor air concentration, C.

 The contaminant concentration in outdoor air is equal to the mean formaldehyde 

concentration in ambient air for industrial land use areas according to the EPA 

exposure assessment (USEPA 2009b), which is equal to 6.28 μg/m3.

 The source generation rate, S, is the rate of formaldehyde off-gassing from the 

three CWP that are present at a CWP fabrication site (which is the only source 

considered in this assessment). This input parameter is expressed as the product 

of the off-gassing emissive flux of formaldehyde (in terms of mass per time per 

composite wood product emitting surface area) and the emitting surface area.

 =

×



+ 

 Eqn (5)

where:

F = Emission rate (off-gassing emissive flux) of formaldehyde from the 

composite wood product (μg/m2-h); and

A = Emitting surface area of the composite wood product (m2).

Formaldehyde off-gassing emissions from CWP decline with time, but this phenomenon is not 

relevant to the estimation of indoor air concentration in a CWP fabrication site because the 

residence time of the CWP at the site is expected to be small (days to weeks) as compared to the 

time required for the emission rate, F, to decline to an extent that would significantly affect the 

resulting indoor air concentration (weeks to months). The concentration, C, becomes the average 

steady-state concentration of airborne formaldehyde due to formaldehyde off-gassing from CWP 

in the entire CWP fabrication site. Section 3.3.1.1 discusses the input parameters in Equation 5 

and their use in the mass balance equation, and the values of these parameters used are shown in 

Table 3-4 of that section. The emissive flux values in Table 3-4 are derived from data in 

Appendix D.
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Page E-3

1.2 Office Buildings Indoor Air Concentration Assessment Method

A mass balance approach similar to the one used for estimating formaldehyde indoor air 

concentration in CWP fabrication sites is used for the estimation of indoor air concentration in 

office buildings. The rate of formaldehyde off-gassing from CWP components of office 

furniture that is expected to be present in a typical office work space is equated to the rate of 

exhaustion of airborne formaldehyde from this typical office work space through ventilation. 

The rate of formaldehyde off-gassing from CWPs is estimated using a formaldehyde source 

model in which the generation rate of formaldehyde is equal to an emission rate multiplied by an 

emitting surface area of the office furniture expected to be present in a typical office work space. 

The rate of exhaustion of indoor air formaldehyde is based on an ASHRAE outdoor air 

ventilation standard for this typical office work space. Several parameters for the model, 

specifically emitting surface area and ventilation rate, are based on the modeling work presented 

in Carter and Zhang, 2007 and the BIFMA M7.1-2005 standard test method. The remaining 

parameter, the emission rate, is determined using data from the EPA market profile (USEPA 

2010a), similarly as was done for the CWP fabrication method, and using other assumptions and 

calculations described in subsection 1.2.3 and 1.2.4 below.

Carter and Zhang attempted to define a standard, representative “worst-case” office environment, 

in support of the BIFMA M7.1-2005 standard test method. Carter and Zhang discussed using the 

BIFMA office environment model to calculate the impact of office furniture on indoor volatile 

organic compound (VOC) concentrations, such as formaldehyde. Steady-state indoor airborne 

formaldehyde concentrations from office furniture in open work space areas and private offices 

are calculated from the office environment model with the following basic components:

 Inputs:

— Outdoor, clean air ventilation flow rate,

— Surface area of composite wood products, and

— Formaldehyde emission rates of composite wood products as a constant 

value;

 Output:

— Steady-state concentration at a specific time (C(t)).

The work by Carter and Zhang assumes the outdoor, clean air does not contain the VOC of 

interest (in this case, formaldehyde). This exposure assessment accounts for observed 

concentrations of formaldehyde in ambient air. This exposure assessment assumes the outdoor 

air used for office building ventilation contains formaldehyde at a concentration equal to the 

mean formaldehyde concentration in ambient air in commercial areas according to the EPA 

exposure assessment (USEPA 2009b).

1.2.1 Calculation Method

The steady-state concentration in a typical office environment due to emissions from an office

workstation system or individual components may be calculated using Equation 6 (Carter and 

Zhang, 2007), which is based on the same mass balance principles as the mass balance model 

used for the CWP fabrication method:
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Page E-4

 =  ×  + 

 Eqn (6)

 =

×



+ 

 Eqn (7)

where:

C = concentration in the defined office environment at the particular time 

(μg/m

3

) due to a specific component;

A = source amount in the office environment (m

2

);

E = estimated emissive flux at a particular time (μg/m

2

-h);

Q = outdoor air ventilation rate in the office environment (m3/h); and

Co

com

= concentration of formaldehyde in the outdoor air for commercial land use 

areas (μg/m3).

The total overall concentration is calculated by summing the contribution from each component. 

This summation results in the following:

 =

∑ ×



+ 

 Eqn (8)

Here, the summation is performed over all workstation components i, where i represents each 

component type of the office workstation.

This model is applied to two office workstation types: open plan workstations and private office 

workstations. The following subsections present the values used for the model parameters for 

both office workstation types. The model parameters are:

 The source amount of each workstation component, Ai, where the components 

are:

— Panels,

— Work surfaces,

— Storage external surfaces;

 The emissive flux of each workstation component, Ei; and

 The outdoor air ventilation rate in the office workstation environment, Q.

1.2.2 BIFMA 2005 Workstation Model Parameters Ai and Q

As used in Carter and Zhang 2007, the BIFMA standard test method M7.1-200513 specifies two 

sets of workstation parameters based on typical open plan and private office environments.14 

These typical workstation parameters are for the purpose of estimating the impact of office 

furniture on the VOC concentrations in office spaces. For a “typical open plan office 

environment of a single workstation system,” BIFMA specifies:

 

13 Updated test method M7.1-2007 has since been published with identical workstation parameters. BIFMA M7.1-

2007 has also been adopted by ANSI as an ANSI standard.

14 The state of CA has also adopted the BIFMA standards for open plan workstations: CA, 2007. California 

Department of Public Health. Open Office Panel Systems Indoor Air Quality Specification.
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Page E-5

 Total workstation area dimensions: floor area of 5.94 m2(64 ft2) by 2.74 m high

(9 ft high) (576 ft3or 16.3 m3);

 Accounts for standard 1.83 m x 1.83 m (6 ft x 6 ft) open plan workstation system, 

traffic area and support space (copiers, files, storage, etc.); and

 Outdoor air ventilation rate (Q) of 4.17 L/s (8.84 cfm) (minimum required 

ventilation rate per ASHRAE Standard 62.1-2004).

For a “typical private office environment of a single workstation system,” BIFMA specifies:

 Total office dimensions: floor area of 23.78 m2(256 ft2) by 2.74 m high (9 ft high) 

(2,304 ft3or 65.2 m3);

 Accounts for standard 13.38 m2(144 ft2) private office workstation system, traffic 

area and support space (copiers, files, storage, etc.); and

 Outdoor air ventilation rate (Q) of 9.63 L/s (20.4 cfm) (minimum required 

ventilation rate per ASHRAE Standard 62.1-2004).

Individual open plan and private office workstation component surface areas and outdoor air 

ventilation rates are tabulated in Table E-1.

Table E-1. BIFMA M7.1-2007 Standard Workstation Model Parameters

Workstation 

System Type

Workstation Component Type Surface Area (Ai) Outdoor Air 

Ventilation 

Panel Area Rate (Q)

Work Surface 

Area

Storage Total 

External Area

Open Plan 11.08 m2

(119.3 ft2)

6.103 m2

(65.69 ft2)

4.569 m2

(49.18 ft2)

15.0 m3/h

(8.84 cfm)

Private Office 7.633 m2

(82.16 ft2)

6.734 m2

(72.48 ft2)

10.55 m2

(113.6 ft2)

34.7 m3/h

(20.4 cfm)

To determine the workstation surface areas listed above in Table E-1, Carter and Zhang first 

determined the footprint size for all workstations present on the office building floor plans (4,594 

open plan workstations and 430 private office workstations). The 50th percentile workstation 

footprint size was taken as representative of the standard workstation size, resulting in areas of 

3.34 m2(36 ft2) for an open plan workstation and 13.47 m2(145 ft2) for a private office.

Because total workstation surface areas vary within workstations of identical floor area, the 90th

percentile conditions for total furniture surface area within the 50th percentile workstation 

footprint size were chosen to provide a representative office environment. This resulted in 1,982 

open plan workstations and 142 private offices. Within this data set, the panel, work surface and 

storage surface areas were determined as a percentage of total workstation surface area and 

averaged, resulting in the values presented in Table E-1.

The parameter values in Table E-1 are also presented in Table 3-8 in the main body of the report. 

The ventilation rate values originally presented in Carter and Zhang, 2007 were in units of L/s 

and cfm. The ventilation rate values were converted to units of m3/h for use in the assessment 

method equation.
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Page E-6

1.2.3 Formaldehyde Emissive Flux for Workstation Component Types (Ei)

The BIFMA standard and the work by Carter and Zhang do not contain any information on 

observed formaldehyde emission rates of actual office workstations. Carter and Zhang provide 

example workstation emission rates of formaldehyde but do not discuss the statistical 

significance of these values such as being representative, worst case, etc.

The formaldehyde emission rate of a workstation component is a function of the type of CWP 

that the component is constructed of and the type of finishing, if any, for the CWP. The 

finishing of CWP is the overlay of the CWP with other material that retard emissions from the 

surface on to which they are applied. This effect is described as barrier effectiveness, or a percent 

reduction of the emission rate of the CWP substrate (CPA 2003a). The literature search did not 

yield any information on how the three CWPs are finished and the extent to which they are used 

together and in combination with other material to fabricate the various components of the 

workstations. This information is needed for the estimation of representative values of the 

emissions rates. Due to these data gaps, indoor air formaldehyde concentration was estimated 

for a range of emission rates that is derived from a what-if analysis. For the what-if analysis, the 

panel and work surface components were assumed to be made entirely of a single CWP type, 

with the CWP type changing for each iteration of the what-if analysis. Storage external surfaces 

were assumed to be constructed of materials other than CWPs with no emission of 

formaldehyde. The what-if analysis follows the algorithm described in Section 3.3.1.2 and in

Table 3-6 of the main body of the report.

For each iteration of the what-if analysis, the emissive flux of the workstation component type is 

calculated from the emissive flux (emission rate in units of flux) of the CWP type, extent of 

finishing of the component type, and barrier effectiveness chosen for the given iteration as 

follows:

 =  × (1 − ) ×  +  × (1 − 

) Eqn (9)

where:

Ei = emissive flux of the workstation component type (μg/m2-h) (i = panels, 

work surfaces, or storage external surfaces);

ECWP = emissive flux of the composite wood product used to construct the 

workstation component type (μg/m2-h) (CWP = HWPW, PB, or MDF);

BE = barrier effectiveness of the finishing, or overlay, of the workstation 

component type, expressed as a unitless fraction; and

Fini = fraction of the workstation component surface area that is finished or 

overlayed with a barrier effectiveness of BE, expressed as a unitless 

fraction (i = panels, work surfaces, or storage external surfaces).

The values of ECWP used in Equation 9 are provided in Table 3-8 in the main body of the report, 

which are derived from the tables in Appendix D. The values of BE are also provided in Table 

3-8 in the main body of the report. The barrier effectiveness values used to estimate the low-end 

and high-end concentrations were obtained from CPA (CPA 2007a). The derivation of the 

intermediate value of barrier effectiveness is described in the following subsection (subsection 

1.2.5) of this appendix.
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1.2.4 Ambient Air Formaldehyde Concentration in Commercial Land Use Areas (Co

com)

This exposure assessment assumes the outdoor air used for office building ventilation contains 

formaldehyde at a concentration equal to the mean formaldehyde concentration in ambient air in 

commercial land use areas according to the EPA exposure assessment (USEPA 2009b). Table 

3-8 in Section 3.3.1.2 of the main body of the report provides the value for the concentration of 

formaldehyde in the outdoor air for commercial land use areas, which is 3.26 μg/m3.

The overall equation used to calculate the formaldehyde concentration is presented in Equation 

10. Equation 10 is calculated for each iteration of the algorithm described in Section 3.3.1.2 of 

the main body of the report using the parameter values given in Table 3-8. Recall that it is 

assumed storage external surfaces are not constructed of CWPs and do not emit formaldehyde. 

Therefore, storage external surfaces are not included in Equation 10.

 =

×()×××

×()× × × 



+ 

 Eqn (10)

Note that the emission rates used in this analysis are for new composite wood products and do 

not account for the decay of emissions with time. Therefore, this method to estimate 

formaldehyde exposures in office buildings only accounts for new office furniture and does not 

account for the decay of emission rates with time. Data to describe the decay of emission rates 

with time were not identified.

1.2.5 Determination of Intermediate Value for Barrier Effectiveness

The ANSI / BIFMA M7.1-2007 standard test method specifies a full-scale chamber test method 

for determining VOC emissions of complete workstation systems, workstation components, and 

seating. The determined emissions can then be used to estimate the impact of the workstation on 

the VOC concentration in a typical office environment. The standard test method specifies a 

chamber ventilation rate of 12 to 20 cfm (22 to 36 m3/h) per workstation system during 

emissions testing. BIFMA standard X7.1-2007 is a voluntary standard for meeting VOC 

emission limits from office furniture. This standard specifies a formaldehyde limit of 50 ppb as 

measured using BIFMA M7.1-2007 for all workstation systems types. BIFMA test method 

M7.1-2007 states that the background concentration of the compound of interest (such as 

formaldehyde) in the chamber should be measured prior to conducting the chamber test. This 

background concentration is then subtracted from the measured concentration in the test chamber 

exhaust or return air. Therefore, the resulting concentration, which is equated to the emission 

rate from the workstation divided by the chamber ventilation rate, is a net concentration due only 

to the workstation. The 50 ppb formaldehyde limit is therefore the net concentration determined 

from the chamber test.

To define an intermediate case, EPA assumed a typical office workstation (both open plan and 

private office) meeting the BIFMA X7.1-2007 standard for formaldehyde. EPA estimated that 

100 percent of the workstation panel and 50 percent of the work surface area were coated with a 

barrier of unknown effectiveness. These assumed values are logical bounding values. Work 
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Page E-8

surfaces are expected to be finished on their upper surface, and panels may be finished on both 

surfaces for aesthetic purposes. EPA averaged the pre-baseline emission rates to estimate an 

average CWP emission rate for the workstation panel and work surface areas (see Appendix D

for derivation of the average pre-baseline emission rate). The parameters used are shown in 

Table E-2.

Since chamber testing requires that the net formaldehyde concentration be used to determine the 

emissions from the workstation, the ambient air concentration is subtracted from Equation 10

presented in the previous subsection 1.2.4. The net formaldehyde concentration, Cnet, is then 

used instead in the left-hand side of Equation 10. This new equation is presented below and is 

solved for the intermediate barrier effectiveness using the values for concentration and each 

parameter given in Table E-2.



 =

×()×××

×()× × × 



Eqn (11)

Table E-2. Parameters Used to Determine Intermediate Barrier Effectiveness

Parameter Value Source

Net Formaldehyde Concentration in 

Chamber 61.5 μg/m3

BIFMA X7.1-2007 standard for 

formaldehyde (unit converted from 50 

ppb)

Panel Emission Rate 306.7 μg/m2-h Weighted average of domestic and import

pre-baseline emission rates, averaged over 

all three CWP types (see Section 3 and 

Appendix D)

Work Surface Emission Rate 306.7 μg/m2-h

Storage Panel Emission Rate 0 μg/m2-h Carter 2007a

Panel Area 11.08 m

2

(open plan)

7.633 m

2

(private office) Carter 2007a

Percent Panel Area with Barrier 100% EPA Assumption

Work Surface Area 6.1 m

2

(open plan)

6.734 m

2

(private office) Carter 2007a

Percent Work Surface Area with 

Barrier 50% EPA Assumption

Storage Panel Surface Area 4.57 m

2

(open plan)

10.55 m

2

(private office) Carter 2007a

Storage Panel Surface Area with 

Barrier N/A EPA Assumption

Ventilation Rate 36 m3/h The high-end ventilation rate for chamber 

testing specified in BIFMA M7.1-2007

N/A – Not applicable

The intermediate barrier effectiveness calculated from the parameters for the open plan and 

private office workstations were 71 percent and 65 percent, respectively. These intermediate 

barrier effectiveness values were used for all intermediate indoor air concentration calculations 

for open plan and private office workstations following the algorithm outlined in Section 3.3.1.2

and Table 3-6 in the main body of the report.
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1.3 Calculation of ADC and LADC from Model Results for CWP Fabrication and 

Office Buildings

Model results from Equation 5 and Equation 10 above are inputs to estimate ADC and LADC. 

The average daily concentration (ADC) and lifetime-average daily concentration (LADC) are 

calculated from the concentration for each modeled scenario outlined in Section 3 of the main 

body of the report for each baseline and analytical-option scenario. ADC and LADC are 

calculated from Equation 12 (EPA 2009a).

 =

×××



Eqn (12)

where:

EC = Exposure concentration (μg/m

3

);

C = Contaminant concentration in air (μg/m

3

);

ED = Exposure duration (hr/day; default: 8);

EF = Exposure frequency (days/yr; default: 250);

WY = Working years per lifetime (years; ADC and LADC: 40 years); and

AT = Averaging time (lifetime in years x 365 days/yr x 24 hours/day; ADC: 40 

years, LADC: 70 years).

1.4 Dermal Exposure Assessment Method for All Life Cycle Stages

EPA has two general categories of assessing dermal exposure when measurements are not 

available: (1) quantitative dermal exposure models and (2) qualitative dermal exposure 

assessments. Both categories of dermal exposure assessments are discussed below. EPA has 

developed a series of standard models for quantitatively estimating worker dermal exposures to 

liquid and solid chemicals during various types of activities. To estimate dermal exposure, all of 

these dermal exposure models assume a specific surface area of the skin that is contacted by a 

material containing the chemical of interest, as well as a specific surface density of the material 

on the skin.

EPA has developed a series of standard models for quantitatively estimating worker dermal 

exposures to liquid and solid chemicals during various types of activities. To estimate dermal 

exposure, all of these dermal exposure models assume a specific surface area of the skin that is 

contacted by a material containing the chemical of interest, as well as a specific surface density

of the material on the skin. The models also assume no use of controls or gloves to reduce the 

exposure. These assumptions and default parameters are defined based on the nature of the 

exposure (e.g., one hand or two hand, immersion in material, contact with surfaces). The 

standard EPA dermal model equation is shown in Equation 13 (USEPA 1991a; USEPA 2000b).

 =  × _ ×  ×  Eqn (13)

where:

EXPdermal = Dermal exposure to the liquid or solid chemical per day (mg 

chemical/worker-day);
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AREAsurface = Surface area of the skin that is in contact with liquid or solid 

material containing the chemical (840 cm2; EPA/OPPT 2-Hand 

Dermal Contact with Liquid Model);

Qremain_skin = Quantity of the liquid or solid material containing the chemical that 

remains on the skin after contact (0.7-2.1 mg/cm2-event; 

EPA/OPPT 2-Hand Dermal Contact with Liquid Model);

Fchem = Weight fraction of the chemical of interest in the material being

handled in the activity; and

Nevent = Frequency of events for the activity (EPA default = 1 

event/worker-day).

Dermal doses in this report are estimated in units further normalized by worker body weight, as 

indicated in Equation 14:

_ = ⁄ Eqn (14)

where:

EXPdermal_bw = Dermal exposure to the liquid or solid chemical per day

normalized by worker body weight (mg chemical/kg-day);

EXPdermal = Dermal exposure to the liquid or solid chemical per day (mg 

chemical/worker-day); and

BWworker = Body weight of an average worker (kg; EPA default value = 70 kg 

(USEPA 1997a).

For several categories of exposure, EPA uses qualitative assessments to estimate dermal 

exposure. Table E-4 summarizes these categories and the resulting qualitative dermal exposure 

assessments. Where chemicals were monomers that had been reacted or additives that would not 

likely to be released from a resin matrix, dermal exposures are characterized as not quantifiable.
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Page E-11

Table E-3. Standard EPA Default Values for Use in the Worker Dermal Exposure Models

Default Model Example Activities

AREAsurface

a

(cm2)

Qremain_skin

b

(mg/cm2-

event)

Resulting Contact

AREAsurface × Qremain_skin

(mg/event)

Physical Form: Liquids

EPA/OPPT 1-Hand Dermal Contact 

with Liquid Model

 Liquid sampling activities

 Ladling liquid/bench-scale liquid transfer

420

(1 hand mean)

Low: 0.7

High: 2.1

Low: 290

High: 880

EPA/OPPT 2-Hand Dermal Contact 

with Liquid Model

 Maintenance

 Manual cleaning of equipment and containers

 Filling drum with liquid

 Connecting transfer line

840

(2 hand mean)

Low: 0.7

High: 2.1

Low: 590

High: 1,800

EPA/OPPT 2-Hand Dermal 

Immersion in Liquid Model

 Handling wet surfaces

 Spray painting

840

(2 hand mean)

Low: 1.3

High: 10.3

Low: 1,100

High: 8,650

Physical Form: Solids

EPA/OPPT 2-Hand Dermal Contact 

with Container Surfaces Model

 Handling bags of solid materials (closed or 

empty)

No defaults No defaults < 1,100c

EPA/OPPT 2-Hand Dermal Contact 

with Solids Model

 Solid sampling activities

 Filling/dumping containers of powders, flakes, 

granules

 Weighing powder/scooping/mixing (i.e., dye 

weighing)

 Cleaning solid residues from process equipment

 Handling wet or dried material in a filtration 

and drying process

No defaults No defaults < 3,100c

a - These default values were adopted in the 2000 EPA report on screening-level dermal exposure estimates (USEPA 2000b) and are the mean values for men 

taken from the EPA Exposure Factors Handbook, 1997 (USEPA 1997a).

b - These default values were adopted in the 2000 EPA report on screening-level dermal exposure estimates (USEPA 2000b). The report derived the selected 

ranges of values for liquid handling activities from: U.S. EPA. A Laboratory Method to Determine the Retention of Liquids on the Surface of Hands. U.S. 

Environmental Protection Agency, Office of Pollution Prevention and Toxics, Exposure Evaluation Division. EPA 747-R-92-003. September 1992.

c - These default values were adopted in the 2000 EPA report on screening-level dermal exposure estimates (USEPA 2000b). The report derived values for 

dermal contact for solids handling activities from: Lansink, C.J.M., M.S.C. Breelen, J. Marquart, and J.J. van Hemmen: Skin Exposure to Calcium Carbonate in 

the Paint Industry. Preliminary Modeling of Skin Exposure Levels to Powders Based on Field Data (TNO Report V 96.064). Rijswijk, The Netherlands: TNO 

Nutrition and Food Research Institute, 1996.
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Table E-4. EPA Default Qualitative Assessments for Screening-Level Estimates of Dermal 

Exposure

Category Dermal Assessment

Corrosive substances (pH>12, pH<2) Negligible

Materials at temperatures >140F (60C) Negligible

Cast Solids (e.g., molded plastic parts, extruded 

pellets)

Non-Quantifiable (Some surface contact may occur if 

manually transferred)

“Dry” surface coatings (e.g., fiber spin finishes, 

dried paint)

Non-Quantifiable (If manual handling is necessary and 

there is an indication that the material may abrade from 

the surface, quantify contact with fingers/palms as 

appropriate)

Gases/Vapors Non-Quantifiable (Some contact may occur in the absence 

of protective clothing)

Source: USEPA 1991a

3.0 Converting Units of Concentration

This section presents the methodology for converting between airborne concentrations measured 

in volume- or mole-based parts-per million (ppm) and airborne concentrations measured in 

micrograms per cubic meter (μg/m3). This assessment conducts exposure and dose calculations 

using concentrations in mg/m3or μg/m3depending on the magnitude of the values. This section 

presents concentration units in μg/m3.

To convert the units of concentration between a volume- or mole-based ppm to ug/m3at ambient 

room conditions, it is assumed that the ideal gas law applies to a mixture of formaldehyde and air 

at ambient conditions. The mass-based concentration of formaldehyde in air from the ideal gas 

law is solved for as follows:

 =





=





× 1,000,000  × 1,000 

   Eqn (15)

where:

C = formaldehyde concentration (μg/m3);

m = total mass of formaldehyde (μg);

V = total volume of gas (m3);

y = mole fraction of formaldehyde (mol/mol);

P = total pressure (atm);

M = molecular weight of formaldehyde (g/mol);

R = universal gas constant (m3-atm/kmol-K); and

T = temperature (K).

Here, the mole fraction of formaldehyde, y, is equal to the formaldehyde concentration in partsper million (ppm) divided by one million. At ambient conditions (1 atm and 298 K), with a 
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formaldehyde molecular weight of 30.03 g/mol and a gas constant of 0.082 m3-atm/kmol-K, the 

unit conversion is 1,229 μg/m3per ppm of formaldehyde.

4.0 ASTM E1333 Large Chamber Test Method

In this assessment, an equation is needed to calculate emission rates from the methods used to 

measure them. In this assessment, the ASTM E1333 large chamber test method is used to 

convert between chamber-test measured formaldehyde concentrations (emission levels) and 

emission rates. The equation used is Equation 15 below. This subsection presents some general 

background information on chamber test methods and then describes the ASTM E1333 large 

chamber test method.

The standard method for measuring emissions from composite wood products is to use a test 

chamber (Kim 2007a). The chamber method is based on a mass balance approach that measures 

the mass flow rates of formaldehyde entering and leaving the chamber system at steady-state 

(Hodgson 2007a). Standard chamber methods are either referred to as the large or small 

chamber method based on the specified chamber size. In general, common large chamber 

methods for estimating formaldehyde emissions require minimum chamber sizes between 10 to 

22 cubic meters. In addition to chamber size, large chamber methods specify several test 

parameters, including the loading ratio, air exchange rate, chamber temperature and humidity. 

This section discusses the ASTM E1333 large chamber test method.

The ASTM E1333 has been used by the composite wood product industry for establishing 

compliance of their products with the U.S. Department of Housing and Urban Development 

(HUD) and ANSI standards for formaldehyde emissions (Hodgson 2007a). It is also the 

reference test method specified in CARB’s regulation. The purpose of ASTM E1333 is to 

measure the formaldehyde concentration in air and the emission rate from a number of large test 

samples (composite wood products) containing formaldehyde under conditions designed to 

simulate product use. ASTM E1333 is primarily used for testing newly manufactured panel 

products (ASTM 2002a). Prior to testing, this method requires test samples to be conditioned for 

seven days. During conditioning, the samples must be placed in a manner such that there is a 

minimum of six-inch spacing in-between the panels. The conditioning is followed by a 16- to 

20- hour exposure period in a large-scale chamber. The chamber is operated at specific product 

loading ratios and an air exchange rate that are typical of the indoor environment. Air samples 

are taken from the chamber at steady-state conditions and the formaldehyde concentration is 

analyzed. Table E-5 lists the product-specific loading ratios for the composite wood products of 

interest. Table E-6 lists the test parameters for ASTM E1333.

Table E-5. ASTM E1333 Loading Ratios for Hardwood Plywood, Medium-Density 

Fiberboard, and Particleboard

Composite Wood Product

Loading Ratio (L)

ft2/ft3 m

2

/m3

Hardwood plywood 0.13 0.43

Medium-density fiberboard 0.08 0.26

Particleboard 0.13 0.43
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Table E-6. Specified Parameters for ASTM E1333

Test Parameter ASTM E1333 Value

Loading Ratio (m2/m3) (L) See Table E-5

Minimum Chamber Size (m3) 22.7

Temperature (°C) 25 ±1

Relative Humidity (%) 50 ±4

Air Exchange Rate (h-1) (n) 0.5 ±0.05

Edge Sealing None

Conditioning 7 days ±3 hrs

Test Duration 16 to 20 hrs

The emission rate of formaldehyde is dependent on several parameters. At steady-state 

conditions, the emission rate (ER) or area-specific emission rate of formaldehyde in μg/m2-h is 

calculated as:

 =





×  × 

 Eqn (16)

where:

V = chamber volume (m3);

n = chamber air exchange rate (h

-1

);

C

net

= net formaldehyde chamber concentration (μg/m3); and

A = total surface area of sample (m2).

The emission rate represents the flux of formaldehyde or the mass of formaldehyde emitted per 

unit area of wood material per time (μg/m2-h). As seen in Equation 16, the emission rate is a 

function of the chamber volume, V, and test sample surface area, A. The ratio of these 

parameters is often specified in a large chamber method in terms of a “loading ratio.” Loading 

ratios (L) are calculated as the emitting surface area of the wood sample divided by the chamber 

volume (m2/m3):

 =





, or  =  ×  Eqn (17)

Substituting Equation 17 into Equation 16 yields Equation 18, which is used to calculate 

emission rates from the measured net formaldehyde chamber concentration (emission level) 

using the parameters given in Table E-5 and Table E-6.

 =

×





Eqn (18)

In chamber methods, air is continuously circulated inside the test environment. The area-specific 

air flow rate (m3/m2-h or m/h) is the ratio between the air flow rate Q (m3/h) entering the 

chamber and the total surface area, A, of the test sample. The area-specific air flow rate is also 

calculated as the product of the chamber volume, V, and the air exchange rate, n, divided by the 

test sample surface area as follows.
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=  ×





Eqn (19)

Substituting Equation 17 into 19, the area-specific air flow rate may be expressed as a quotient of 

n/L.





=  ×



×

=





Eqn (20)

After steady-state conditions are achieved, a minimum of two air samples are taken from the 

chamber at a rate of 1±0.05 L/min for 60 minutes ±5 seconds. The quantity of formaldehyde in 

the sample is determined by an adaptation of the National Institute for Occupational Safety and 

Health (NIOSH) 3500 chromotropic acid test procedure (ASTM 2002a), where air is bubbled 

through a 1-percent sodium bisulfite solution and analyzed using a UV-Vis spectrophotometer.
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Appendix F

PRE-BASELINE FORMALDEHYDE EXPOSURES FROM OSHA IMIS BY WORKER 

ACTIVITY AND INDUSTRY SECTOR FOR COMPOSITE WOOD PRODUCT 

FABRICATORS
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Background on IMIS Data

IMIS is designed to collect, process, retrieve, and communicate penalty assessment, arbitration, 

and collection information regarding OSHA inspections. For each data point, the database 

contained information on the following data elements:

 Inspection date;

 Identity of inspected facility;

 Inspection type (e.g., inspection in response to a complaint, referral, or as part of a 

program);

 Worker job description;

 Exposure concentration;

 Exposure concentration measurement type (personal or area monitoring);

 Exposure type (i.e., time weighted average (TWA) or peak exposure);

 Frequency or duration of exposure;

 Number of employees at the inspected facility;

 Number of employees exposed; and

 Applicable OSHA PEL.

OSHA IMIS data for most of the NAICS codes given in Table 2-1 were obtained from OSHA in 

June 2010. The OSHA occupational exposure limits for formaldehyde are given in Appendix C.

The “exposure types” for the obtained data include TWA, STEL, ceiling, peak exposures or not 

detected or not found. Only TWA data were used to develop exposure estimates (in terms of 

average daily concentrations (ADCs) and lifetime-average daily concentrations (LADCs)). 

STEL, ceiling, and peak measurements are not representative of daily average concentration 

levels and were therefore excluded (refer to Appendix A for a definition of these terms). Also, 

measurements that resulted in a non-detected formaldehyde concentration do not include their 

measurement type in the OSHA IMIS database (i.e., TWA or STEL measurement type). 

Therefore, it is unknown whether a non-detected value was the result of a measurement over an 

extended duration of time for the purpose of determining TWA exposure or measurement over a 

fifteen-minute duration. For this reason, non-detected and not-found results were excluded 

except as discussed below.

Additionally, only personal monitoring data were included in the assessment except in the case 

of the retail life cycle stage. IMIS contains few personal monitoring data from 2002 and onward 

for this life cycle stage, and the inclusion of area monitoring data approximately doubled the 

number of included data points. Most of these area monitoring data have non-detect values. 

Area monitoring data in a strictly retail setting are considered representative of potential worker 

exposure and are expected to be TWA data. The non-detected value was set equal to the lowest 

reliable quantitation limit (RQL) identified among OSHA’s sampling and analysis methods for 

formaldehyde. The RQL was identified as 0.00058 ppm (OSHA 2010b). Also, any detected 

values for all life cycle stages less than this RQL were set equal to the RQL.
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Grouping Data by Worker Activity

This appendix presents a summary of OSHA IMIS data for CWP fabrication industry sectors 

grouped by their worker activity. This grouping was performed as part of this exposure 

assessment to provide perspective as to the different worker activities monitored by OSHA and 

to present statistics of the monitoring data according to worker activity. There is some 

uncertainty about the worker activities recorded in IMIS. The worker activities were not 

recorded or identified in a consistent manner in IMIS. For example, for CWP fabrication, gluing 

activities are identified as “apply wood glue” and “glue machine operator”. Therefore, this 

appendix presents OSHA IMIS data grouped such that similar worker activities are grouped into 

a single worker activity category. Additionally, some worker activities are similar or can be 

expected to result in similar exposures, such as “sawing”, “routing”, and “cutting”, and are 

compiled into a single category. Other worker activities are compiled into a single category due 

to uncertainty in the exact job description, such as “wood worker”, “laborer”, or “operator”. 

Table F-1 presents a summary of the TWA, personal monitoring data from OSHA IMIS for 

CWP fabrication organized by worker activity description categories.
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Table F-1. Pre-Baseline Formaldehyde Exposures by Organized by Worker Activity Category for Composite Wood Product 

Fabricators from OSHA IMIS

Industry

Worker 

Activity 

Description

Number of 

Sites 

Monitored

Number of 

Data Points

Monitored 

Formaldehyde 

Concentration 

(ppm)

Monitored 

Formaldehyde 

Concentration 

(mg/m3) Year

Description of 

Concentration 

Level

Wood Kitchen 

Cabinets and 

Countertop 

Manufacturing

Painting / 

Laminating / 

Finishing / 

Spraying

14 22

0.69 0.85 2003 Maximum

0.15 0.18 2004, 

2007 Median

0.0006 0.001 2004 Minimum

Fabricating / 

Assembling / 

Building

1 1 0.2 0.25 2004 1 Data Point

Other Operations 

/ Maintenance 1 2

0.52 0.639 2004 Maximum

0.28 0.343 2004, 

2004 Median

0.038 0.047 2004 Minimum

Sawing / Cutting 

/ Routing 1 2

0.070 0.086 2005 Maximum

0.054 0.066 2005, 

2005 Median

0.037 0.046 2005 Minimum

Sanding 1 1 0.035 0.043 2003 1 Data Point

Compliance, 

Safety, and 

Health Officer

1 1 0.025 0.031 2006 1 Data Point

Upholstered 

Household 

Furniture 

Manufacturing

Painting / 

Laminating / 

Finishing / 

Spraying

1 2

0.092 0.11 2004 Maximum

0.06 0.074 2004, 

2004 Median
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Table F-1. Continued

Industry

Worker 

Activity 

Description

Number of 

Sites 

Monitored

Number of 

Data Points

Monitored 

Formaldehyde 

Concentration 

(ppm)

Monitored 

Formaldehyde 

Concentration 

(mg/m3) Year

Description of 

Concentration 

Level

0.028 0.034 2004 Minimum

Other Operations 

/ Maintenance 2 3

0.11 0.137 2003 Maximum

0.04 0.049 2004 Median

0.04 0.049 2004 Minimum

Gluing 1 1 0.009 0.011 2003 1 Data Point

Nonupholstered 

Household 

Furniture 

Manufacturing

Painting / 

Laminating / 

Finishing / 

Spraying

8 10

0.59 0.73 2004 Maximum

0.330 0.405 2008, 

2007 Median

0.031 0.038 2008 Minimum

Fabricating / 

Assembling / 

Building

1 1 0.22 0.27 2007 1 Data Point

Other Operations 

/ Maintenance 1 5

0.1129 0.139 2009 Maximum

0.0625 0.077 2009 Median

0.0278 0.034 2009 Minimum

Compliance, 

Safety, and 

Health Officer

3 3

0.14 0.172 2008 Maximum

0.089 0.109 2009 Median

0.0712 0.088 2008 Minimum
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Table F-1. Continued

Industry

Worker 

Activity 

Description

Number of 

Sites 

Monitored

Number of 

Data Points

Monitored 

Formaldehyde 

Concentration 

(ppm)

Monitored 

Formaldehyde 

Concentration 

(mg/m3) Year

Description of 

Concentration 

Level

Wood Office 

Furniture 

Manufacturing

Painting / 

Laminating / 

Finishing / 

Spraying

4 8

0.58 0.713 2004 Maximum

0.055 0.068 2004, 

2005 Median

0.009 0.011 2004 Minimum

Fabricating / 

Assembling / 

Building / 

Laboring

1 1 0.02 0.025 2004 1 Data Point

Other Operations 

/ Maintenance 1 2

0.04 0.049 2005 Maximum

0.03135 0.039 2005, 

2005 Median

0.0227 0.028 2005 Minimum

Sawing / Cutting 

/ Routing 2 4

0.067 0.082 2004 Maximum

0.049 0.060 2004, 

2004 Median

0.0048 0.006 2004 Minimum

Sanding 1 3

0.028 0.034 2005 Maximum

0.027 0.033 2005 Median

0.0219 0.027 2005 Minimum

Institutional 

Furniture 

Manufacturing

Painting / 

Laminating / 

Finishing / 

Spraying

3 3

0.21 0.258 2005 Maximum

0.06 0.074 2007 Median

0.0189 0.023 2002 Minimum
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Table F-1. Continued

Industry

Worker 

Activity 

Description

Number of 

Sites 

Monitored

Number of 

Data Points

Monitored 

Formaldehyde 

Concentration 

(ppm)

Monitored 

Formaldehyde 

Concentration 

(mg/m3) Year

Description of 

Concentration 

Level

Other Operations 

/ Maintenance 2 3

0.10 0.123 2007 Maximum

0.06 0.074 2007 Median

0.01 0.012 2002 Minimum

Showcase, 

Partition, Shelving, 

and Locker 

Manufacturing

Painting / 

Laminating / 

Finishing / 

Spraying

2 3

0.228 0.280 2004 Maximum

0.216 0.265 2004 Median

0.13 0.160 2005 Minimum

Press Operating 1 2

0.187 0.230 2004 Maximum

0.138 0.169 2004, 

2004 Median

0.088 0.108 2004 Minimum

Compliance, 

Safety, and 

Health Officer

1 1 0.184 0.226 2004 1 Data Point

Custom 

Architectural 

Woodwork and 

Millwork 

Manufacturing

Other Operations 

/ Maintenance 1 3

1 1.229 2008 Maximum

0.44 0.541 2008 Median

0.04 0.049 2008 Minimum

Sawing / Cutting 

/ Routing 1 1 0.068 0.084 2004 1 Data Point

Other Millwork 

(including flooring) 

Manufacturing

Painting / 

Laminating / 

Finishing / 

Spraying

1 1 0.13 0.160 2003 1 Data Point

Fabricating / 1 2 0.075 0.092 2002 Maximum
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Table F-1. Continued

Industry

Worker 

Activity 

Description

Number of 

Sites 

Monitored

Number of 

Data Points

Monitored 

Formaldehyde 

Concentration 

(ppm)

Monitored 

Formaldehyde 

Concentration 

(mg/m3) Year

Description of 

Concentration 

Level

Assembling / 

Building / 

Laboring

0.03805 0.047 2002, 

2002 Median

0.0011 0.001 2002 Minimum

Other Operations 

/ Maintenance 2 3

0.243 0.299 2006 Maximum

0.184 0.226 2006 Median

0.0992 0.122 2002 Minimum

Sawing / Cutting 

/ Routing 1 1 0.05 0.061 2004 1 Data Point

Press Operating 2 3

0.55 0.676 2008 Maximum

0.317 0.390 2008 Median

0.06 0.074 2004 Minimum

Wood Window and 

Door 

Manufacturing

Painting / 

Laminating / 

Finishing / 

Spraying

1 1 0.00438 0.005 2007 1 Data Point

Fabricating / 

Assembling / 

Building / 

Laboring

2 2

0.24 0.295 2006 Maximum

0.1465 0.180 2006, 

2009 Median

0.053 0.065 2009 Minimum

Motor Home 

Manufacturing Trailer Cleaning 1 1 0.0023 0.003 2002 1 Data Point

All Other All Activities 8 18 1.00 1.229 2005 Maximum
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page F-8

Table F-1. Continued

Industry

Worker 

Activity 

Description

Number of 

Sites 

Monitored

Number of 

Data Points

Monitored 

Formaldehyde 

Concentration 

(ppm)

Monitored 

Formaldehyde 

Concentration 

(mg/m3) Year

Description of 

Concentration 

Level

Miscellaneous 

Wood Product 

Manufacturing

0.144 0.177 2005, 

2006 Median

0.003 0.003 2003 Minimum

Table F-2 through Table F-12 present summary statistics of the TWA, personal monitoring data from OSHA IMIS by NAICS code for the 

CWP fabrication life cycle stage. Not all NAICS codes within CWP fabrication are included in this summary; only NAICS codes for which 

data were obtained from OSHA IMIS.

Table F-2. Summary Statistics for Pre-Baseline Monitoring Data for NAICS Code 321911

Monitored Formaldehyde Concentration Number of 

Monitored Sites

Number of Data 

(ppm) (μg/m Points Year 3)

Maximum 0.24 295.0

3 3

2006

Median 0.053 65.1 2009

Minimum 0.0044 5.4 2007

Mean 0.099 121.8 N/A

Standard 

deviation 0.124 152.9 N/A
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October 6, 2011

Page F-9

Table F-3. Summary Statistics for Pre-Baseline Monitoring Data for NAICS Code 321918

Monitored Formaldehyde Concentration Number of 

Monitored Sites

Number of Data 

(ppm) (μg/m Points Year 3)

Maximum 0.55 676.0

6 10

2008

Median 0.1146 140.8 N/A

Minimum 0.0011 1.4 2002

Mean 0.17093 210.1 N/A

Standard 

deviation 0.164 201.6 N/A

Table F-4. Summary Statistics for Pre-Baseline Monitoring Data for NAICS Code 337110

Monitored Formaldehyde Concentration Number of 

Monitored Sites

Number of Data 

(ppm) (μg/m Points Year 3)

Maximum 0.69 848.0

16 29

2003

Median 0.137 168.4 2004

Minimum 0.0006 0.7 2004

Mean 0.197 242.6 N/A

Standard 

deviation 0.204 250.9 N/A
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Page F-10

Table F-5. Summary Statistics for Pre-Baseline Monitoring Data for NAICS Code 337121

Monitored Formaldehyde Concentration Number of 

Monitored Sites

Number of Data 

(ppm) (μg/m Points Year 3)

Maximum 0.111 136.6

3 6

2003

Median 0.040 49.2 N/A

Minimum 0.009 11.1 2003

Mean 0.053 65.6 N/A

Standard 

deviation 0.039 48.5 N/A

Table F-6. Summary Statistics for Pre-Baseline Monitoring Data for NAICS Code 337122

Monitored Formaldehyde Concentration Number of 

Monitored Sites

Number of Data 

(ppm) (μg/m Points Year 3)

Maximum 0.590 725.1

11 19

2004

Median 0.170 208.9 2008

Minimum 0.028 34.2 2009

Mean 0.222 273.4 N/A

Standard 

deviation 0.182 223.7 N/A
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Page F-11

Table F-7. Summary Statistics for Pre-Baseline Monitoring Data for NAICS Code 337127

Monitored Formaldehyde Concentration Number of 

(ppm) (μg/m Monitored Sites Number of Data Points Year 3)

Maximum 0.210 258.1

3 6

2005

Median 0.060 73.7 N/A

Minimum 0.010 12.1 2002

Mean 0.076 94.0 N/A

Standard 

deviation 0.073 89.8 N/A

Table F-8. Summary Statistics for Pre-Baseline Monitoring Data for NAICS Code 337211

Monitored Formaldehyde Concentration Number of 

Monitored Sites

Number of Data 

(ppm) (μg/m Points Year 3)

Maximum 0.580 712.8

6 18

2004

Median 0.029 35.6 N/A

Minimum 0.005 5.9 2004

Mean 0.082 100.9 N/A

Standard 

deviation 0.140 171.5 N/A
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October 6, 2011

Page F-12

Table F-9. Summary Statistics for Pre-Baseline Monitoring Data for NAICS Code 337212

Monitored Formaldehyde Concentration Number of 

Monitored 

(ppm) (μg/m Sites Number of Data Points Year 3)

Maximum 1.00 1229

2 4

2008

Median 0.25 312.2 N/A

Minimum 0.04 49.2 2008

Mean 0.39 475.6 N/A

Standard 

deviation 0.45 550.0 N/A

Table F-10. Summary Statistics for Pre-Baseline Monitoring Data for NAICS Code 337215

Monitored Formaldehyde Concentration Number of 

Monitored Sites

Number of Data 

(ppm) (μg/m Points Year 3)

Maximum 0.23 280

3 6

2004

Median 0.19 228.0 N/A

Minimum 0.09 108.2 2004

Mean 0.17 211.6 N/A

Standard 

deviation 0.05 65.6 N/A
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Page F-13

Table F-11. Summary Statistics for Pre-Baseline Monitoring Data for NAICS Code 336213

Monitored Formaldehyde 

Concentration

Number 

of 

Monitored 

Sites

Number 

of Data 

(ppm) (μg/m Points Year 3)

Single 

Data 

Point

0.0023 2.8 1 1 2002

Table F-12. Summary Statistics for Pre-Baseline Monitoring Data for NAICS Code 321999

Monitored Formaldehyde Concentration Number of 

Monitored Sites

Number of Data 

(ppm) (μg/m Points Year 3)

Maximum 1.00 1229

8 18

2005

Median 0.14 177.0 N/A

Minimum 0.003 3.4 2003

Mean 0.20 249.6 N/A

Standard 

deviation 0.26 313.6 N/A
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Appendix G

SUMMARY OF OSHA INSPECTION REPORTS
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October 6, 2011

Page G-1

One data gap of the exposure assessment is the use of personal protective equipment (PPE) in 

manufacturing facilities. To help resolve this data gap, OSHA inspection reports associated with 

the obtained OSHA IMIS data were obtained from OSHA. This appendix summarizes the PPE 

information found in the reports received as of January 2011.

Table G-1 and the following sections present the findings of the review of the inspection reports 

received.

Table G-1. Summary of OSHA Inspection Reports and Findings on PPE Use

Name of Inspected Facility

Personal Protective Equipment 

(PPE) Worn by Workers 

During Inspection

Respirator Use During 

Inspection

Manufacturing

Carolina Curves

Inspection No. 303713325

Ear plugs, safety glasses/goggles, 

aprons

No

McKnight Plywood

Inspection No. 123445595

Safety glasses, rubber gloves, 

back braces

No

Marshfield Door Systems

Inspection No. 303864029

Safety glasses, gloves No

Fiberesin Industries

Inspection No. 307061689

Safety glasses, gloves, eye 

protection

No

Unilin Flooring NC, LLC

Inspection No. 312479835

3M 6300 half mask with 

formaldehyde cartridges

Yes

Composite Wood Product Fabrication

Plymart Inc.

Inspection No. 308245372

Unknown No

Bushline Inc.

Inspection No. 306132275

Half face air purifying respirator Yes

England Inc.

Inspection No. 307674051

Safety glasses, smock, hearing 

protection

No

Commercial Furniture Group

Inspection No. 311144059

Safety glasses and hearing 

protection

No

Harris Tarkett

Inspection No. 307206987

Safety glasses, gloves, and 

hearing protection

No

Gunlocke Company

Inspection No. 307690578

Unknown No

Armstrong Cabinets

Inspection No. 306021239

Gloves, apron No

Wood Goods Industries, Inc.

Inspection No. 307041707

Respirator with organic vapor 

cartridge, nitrile gloves, safety 

glasses, hard hat, ear plugs, and 

steel toe shoes

Yes (not required)

Parenti & Rafaelli, Ltd

Inspection No. 305228652

Safety glasses, steel toe shoes, 

gloves, and half-face respirators. 

Dust masks are also available for 

use. 

Yes

Benvenuti and Stein

Inspection No. 312188972

Half-face cartridge respirator, 

safety glasses, safety shoes

Yes

Ameriwood Industries Inc.

Inspection No. 311606883

Safety glasses, ear plugs No
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Page G-2

Table G-1. Summary of OSHA Inspection Reports and Findings on PPE Use

Name of Inspected Facility

Personal Protective Equipment 

(PPE) Worn by Workers 

During Inspection

Respirator Use During 

Inspection

Tru-Wood Cabinets, Inc.

Inspection No. 307013250

Safety glasses, earplugs No

Jimson Manufacturing Co.

Inspection No. 303424014

Safety glasses No

Newood Display Fixtures 

Manufacturing Company

Inspection No. 304064835

Respirator Yes

Simple Designs Manufacturing

Inspection No. 306629171

Safety glasses, gloves, ear 

protection; dust masks are 

“available for use”

No

1.0 MANUFACTURING

Carolina Curves Inc., Inspection 303713325

The inspection occurred as a result of referral. Carolina is primarily engaged in the manufacture 

of curved plywood products for the furniture industry (e.g., chairs, bed posts, and other furniture 

items). These operations include receiving plywood, laminated veneer using an amino resin 

containing formaldehyde (0.1 – 0.5%), mold pressing of veneer (using pressure/Rf to curve 

plywood), wood cutting, sanding, shaping operations. Inspection of the curved wood products is 

the final phase of the curved plywood operation prior to shipping. According to the air sampling

reports, workers may wear ear plugs, safety glasses/goggles and aprons as PPE. These reports 

did not indicate the use of a respirator during any of the inspected activity.

McKnight Plywood, Inspection 123445595

This inspection was a planned health inspection. McKnight Plywood makes laminated hardwood 

plywood products such as hardwood flooring using purchased veneers and formaldehyde-based 

glues (0.21% formaldehyde in the glue used in the old building and 0.32% in the glue used in the 

flooring plant). Some of the operations at McKnight Plywood include plywood sorting, glue 

application, pressing, cooling, cutting and sanding the finished products.

OSHA cited the facility for formaldehyde overexposure. However, based on the inspection 

summary and the air sampling reports, the only PPE worn at the facility are safety glasses, rubber 

gloves, and back braces. These PPE are only worn in some areas of the facility.

Marshfield Door Systems, Inc. Inspection 303864029

The inspection occurred as a result of a complaint. Workers at the inspected facility are 

potentially exposed to formaldehyde in the smoke emitted from the electronic press. Air 

sampling reports from the inspection indicated the use of PPE such as safety glasses and gloves 

by some workers. Respirators were not worn.
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Page G-3

Fiberesin Industries, Inc., Inspection 307061689

The inspection occurred as a result of a complaint. Fibersin Industries manufactures 

particleboard. Air monitoring during the inspection indicated no overexposure to formaldehyde 

at the inspected facility. Because no overexposures were found, it is not mandatory for the 

employer to provide workers with respiratory protection. Eye protection is provided to workers, 

but the wearing of eye protection is not enforced. PPE for the press operator include the 

occasional use of gloves and the use of safety glasses and hearing protection.

Unilin Flooring NC, LLC., Inspection No. 312479835

OSHA conducted a partial inspection of the facility as a result of a non-formal complaint. The 

inspection did not cover all operations at the facility and OSHA did not identify any violation of 

OSHA standards or regulations. The inspected facility manufactures high density MDF used 

primarily in flooring material. The company provides respiratory protection training and fit 

testing for workers in the production area. Workers were wearing 3M 6300 half masks with 

formaldehyde cartridges; they also had the option of using full face cartridge respirators and had 

been fit tested of both types of respirators. The company also conducts periodic formaldehyde 

sampling and has performed a ventilation study on-site.

2.0 COMPOSITE WOOD PRODUCT FABRICATION

Plymart Inc. Inspection No. 308245372

Plymart is a high production cabinet shop with a series of large warehouse size buildings. The 

cabinets are mainly constructed of particleboard frames with hardwood doors. OSHA conducted 

a combined safety and health programmed inspection at the facility and cited Plymart for poor 

ventilation and housekeeping in the spray finish booth. However, air sampling throughout the 

facility indicated that concentrations of formaldehyde, as well as dust and solvent were all below 

the PEL and that there was no overexposure. Hence, the company had “decided not to require 

tight fitting respirators.”

Bushline Inc. Inspection No. 306132275

This inspection was a general schedule comprehensive occupational health inspection. Bushline 

manufactures upholstered furniture. During the OSHA inspection, the facility was cited for poor 

ventilation in the spray booth, the lack of PPE hazard assessment or employee training 

certification, lack of impervious gloves and clothing for workers handling corrosive liquids, as 

well as eye and face protection for employees potentially exposed to hazards from acids or 

caustic chemicals.

Formaldehyde glue is mixed and applied by hand to glue wood sections together in the rough 

mill area. The report stated that “proper PPE and an eyewash and shower were not provided in 

this area” and that formaldehyde sampling results were below the action level.

An employee wore the Cabot Safety half face air purifying respirator while mixing the adhesive 

in the chair line area, where wooden frame chairs are assembled using pneumatic guns and a 

formaldehyde glue. Past air sampling indicated that the formaldehyde concentration was below 

the PEL in this area.
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Page G-4

England Inc. Inspection No. 307674051

This inspection was a general schedule comprehensive occupational health inspection. England 

Inc. manufactures furniture cushions and mattresses. During the inspection, the facility was cited 

for not providing the proper PPE where there is potential for exposure. The only worker PPE 

(worn in select areas of the facility) are safety glasses, smock, and hearing protection. It appears 

that no respirators were worn. The facility uses a water-based non-toxic glue in its processes, and 

sampling results show formaldehyde exposure below the OSHA PEL.

Harris-Tarkett Inc. Inspection No. 307206987

This inspection was a general schedule comprehensive occupational health inspection. During 

the inspection, workers were observed to wear a combination of safety glasses, gloves, and 

hearing protection in the wood processing area, and in the long strip area, where wood products 

are being sorted, cut, glued, pressed and finished. It appears that no respirator was worn in the 

areas with potential formaldehyde exposure. Respirators were also not worn by workers in the 

chemical room of the finishing department where they were exposed to methyl isobutyl ketone 

above the PEL and STEL levels.

The Commercial Furniture Group. Inspection No. 311144059

This inspection was a general schedule comprehensive occupational health inspection. The 

Commercial Furniture Group manufactures wooden chairs at the inspected facility. The 

operation here consists of a rough mill, a frame assembly area, a spray finishing area, a fabric 

cutting and storage area, and an upholstery area. The inspection report did not indicate the use of 

formaldehyde-based adhesives although formaldehyde could be emitted from the wood boards 

used to manufacture chairs. According to the report, workers wear safety glasses and hearing 

protection in certain areas of the facility. There was no indication for respiratory use. Air 

sampling results also indicate the formaldehyde concentration was below the OSHA PEL, 

therefore, the facility would not be required to provide respirators for formaldehyde exposures.

Gunlocke Company, LLC. Inspection No. 307690578

The inspection at Gunlocke Company was conducted as a result of a compliant. During the 

inspection, the observed workers were not wearing respirators.

Armstrong Cabinets Products. Inspection No. 306021239

This inspection was a planned health inspection. Armstrong Cabinets manufactures bath and 

kitchen wood cabinets. OSHA cited the company for not providing protective eye and face 

equipment to prevent chemical splashes. The facility has a written respiratory protection program 

but the use of a respirator is not mandatory. During the inspection, workers were not wearing 

respirators or dust masks even though the facility has seven spray booths. Occasional PPE worn 

include apron and gloves.

Wood Goods Industry Inc. Inspection No. 307041707

The inspection was conducted as a result of a complaint. The inspection summary suggests that 

this facility produced various wood products, such as tables, from rough lumber. Lumber was 

rip-sawed, chopped, and glued with non-hazardous wood glue (does not contain formaldehyde). 

The facility also had a spray operation where three chemical sprays, a water based stain, a vinyl

sealer, and a clear top coat were sprayed onto the wood products. Employees rotated between 
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page G-5

spraying operations and hand sanding, wiping stains, and setting tables on the conveyor tracks. 

Air sampling for formaldehyde was conducted on an employee spraying the top coat. The other 

two coatings do not appear to contain formaldehyde.

The facility had an operational spray booth in place but did not require respirator use. During air 

sampling of spraying activities, only some workers were observed to wear a respirator with 

organic vapor cartridges. Other PPE worn by workers during air sampling include nitrile gloves, 

safety glasses, hard hat, ear plugs, and steel toe shoes.

Parenti & Rafaelli, Ltd. Inspection No. 305228652

The inspection was conducted under the Site Specific Targeting program. A safety inspection 

had been initiated previously and the health inspection was initiated to address health issues such 

as spray booths, exposure to wood dust and formaldehyde. The company had no previous history

of OSHA inspections.

The company required the use of half face respirators in the spray booth and dust masks are 

available to the rest of the employees. The company also required employees to wear safety 

glasses, steel toe shoes, gloves, and respirators in the spray booths.

The company made custom millwork and woodwork for commercial and residential sites. The 

types of wood used vary depending on customer specification but includes fir, pine, oak, maple, 

mahogany, cherry and particleboard. Air sampling for formaldehyde was below the PEL.

Benvenuti and Stein, Inc. Inspection No. 312188972

The health inspection was initiated due to a non-formal complaint regarding a chemical spill. 

The company made custom design wooden cabinets and the facility was divided into cabinet 

making, cabinet finishing, and the dock. The finish coating used during the spray operation 

contained formaldehyde.

The company provided a half-face cartridge respirator to reduce employee exposure to 

formaldehyde but did not implement a written respirator program. Other PPE worn by workers 

include safety glasses and safety shoes.

Ameriwood Industries Inc. Inspection No. 311606883

OSHA conducted this partial health inspection as follow-up to a previous inspection that was 

conducted in response to a complaint. OSHA determined that the formaldehyde exposure for 

workers operating the autodrill was well under the PEL based on personal monitoring. Workers 

only wore safety glasses and ear plugs during air sampling.

Tru-Wood Cabinets, Inc. Inspection No. 307013250

OSHA conducted this partial health inspection in response to a complaint. Tru-Wood Cabinets, 

Inc. manufactures wood cabinets (kitchen and bathroom) to be installed on new homes. At the 

time of inspection, the company employed 279 employees in two working shifts. The company 

had two buildings: frame door production and spray painting operations were conducted in 

building #1, while panel cutting and finishing occurred in building #2.
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October 6, 2011

Page G-6

Monitoring data show exposure for formaldehyde was below the OSHA PEL. The only PPE 

listed in OSHA’s air sampling worksheets were safety glasses and ear plugs. The inspection 

report indicates voluntary use of particulate masks by workers in building #2; however, it was 

uncertain how frequent these respirators were being worn.

Jimson Manufacturing Co. Inspection No. 303424014

OSHA conducted this partial health inspection in response to a complaint. This company

manufactures furniture for retail stores. Sheets of MDF are received at the company (facility) and 

the wood is cut to size using panel saws. Foil is applied to edges and flat pieces of wood via heat 

and pressure; and furniture is assembled with staple guns.

OSHA monitoring indicates that the formaldehyde exposure level was well below the OSHA 

PEL. The PPE listed in OSHA’s air sampling worksheets included prescription glasses and 

safety glasses (with or without side shields). Dust masks and respirators were not worn.

Newood Display Fixtures Manufacturing Company. Inspection No. 304064835

Newood Display Fixtures Manufacturing is a large store fixture manufacturer with a staff of 60 

employees. The health inspection was initiated based on an anonymous complaint alleging 

exposure to lacquer, paints, and formaldehyde in the west end of the mill. Some of the operations 

that occur at this facility include spray painting operation, glue-up, and packing. The spray area 

consists of three spray rooms and a spray painting prep area. The lacquer pump is electrically 

interconnected to the ventilation system, so that the spray guns will not operate if the ventilation 

system is inoperable. Sampling results indicated that formaldehyde TWA reached 0.299 and 

0.276 ppm; however, the 8-hour TWA were quite low due to the shortness of the sampling 

period. The inspection did not result in a citation.

The only PPE listed in the air sampling report is 3M-N95-8210. This appears to refer to the N95 

disposable particulate respirator model 8210.

Simple Designs Manufacturing Inc. Inspection 306629171

This inspection was a partial health inspection conducted as a result of a complaint. The 

inspected facility makes furniture using plywood, hardboard, particleboard, and oriented strand 

board (OSB). The company safety process manual states that safety glasses and ear protection 

must be worn throughout the mill area. Gloves are also required in some areas of the plant. Dust 

masks are available for use. Air sampling reports also indicate the occasional use of an apron. 

However, none of the workers inspected wore a respirator.
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October 6, 2011

Appendix H

SUMMARY OF ADDITIONAL EXPOSURE MONITORING DATA FROM 

MANUFACTURING
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October 6, 2011

Page H-1

Table H-1. Formaldehyde Exposure Levels for Plywood, Particleboard, and Medium-Density Fiberboard Manufacture

Authors/Articles Publication

Air 

Concentrations of 

Formaldehyde 

Study Population

(Exposed 

Workers) Abstract and Salient Points

The Workers’ 

Compensation 

Board BC 

(WorkSafeBC)

Discussion Paper –

Occupational 

exposure limit for 

formaldehyde. 

March 20, 2007

Not Applicable Plywood 

manufacturing: 

predominantly 

below 0.3 ppm as 

8-hour TWA

Pressed/panel 

particle/fiberboard 

manufacturing: 0.3 

ppm as 8-hour 

TWA exceeded at 

times with an 

exposure range of 

0.07 to 5.00 ppm

Workers in a 

variety of industries 

in British Columbia 

including those in 

the pressed/panel 

particle/fiberboard 

manufacturing 

facilities.

Abstract: 

None Available

Salient Points:

 Sampling data collected by WorkSafeBC over a period of 15 years (1990 to 

2005) in British Columbia and other locations, including Ontario, Quebec, 

and the Netherlands indicate that worker exposure to formaldehyde is likely 

to occur primarily in the forest panel board manufacturing sector (plywood, 

particle/fiberboard, oriented strand board, laminated wood products 

manufacturing), resin manufacture, acute care hospitals, university and 

other laboratories, and funeral homes.

 The exposure data indicate that, overall, exposure levels have decreased 

over time as control and procedural measures have improved. This is 

particularly evident when one compares readings taken in the early 1980s 

with those in the late 1990s.

 The results indicate that industries in which exposure levels were 

predominantly below the current 0.3 ppm 8-hour TWA exposure limit 

include: 

- Foundries; 

- Resin manufacturing; and 

- Plywood manufacturing. 

 Industries in which the current 0.3 ppm 8-hour TWA exposure limit (for 

British Columbia) was exceeded include (range of exposure shown):

- Paperboard & cardboard manufacturing (0.04 to 0.38 ppm);

- Laminated wood products manufacturing (0.24 to 0.38 ppm); 

- Pressed/panel particle/fiberboard manufacturing (0.07 – 5.00 

ppm); 

- Oriented strand board manufacturing (0.03 to 0.32 ppm); 

- Funeral homes (none detected to 0.74 ppm); 
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Page H-2

Table H-1. Formaldehyde Exposure Levels for Plywood, Particleboard, and Medium-Density Fiberboard Manufacture

Authors/Articles Publication

Air 

Concentrations of 

Formaldehyde 

Study Population

(Exposed 

Workers) Abstract and Salient Points

- University laboratories (0.52 to 1.15 ppm); 

- Hospitals & medical clinics and laboratories (0.02 to 1.35 ppm); and 

- Poultry hatcheries (0.1 – 0.35 ppm). 

 Formaldehyde exposure levels in a plywood manufacturing plant in 2002, 

as reported by the Ontario Ministry of Labour, ranged from 0.16 to 0.17 

ppm as 8-hour TWA, with a 15-minute STEL range of 0.14 to 0.29 ppm and 

instantaneous ceiling limit values ranging from 0.33 to 0.44 ppm.

 Formaldehyde exposure levels in two particleboard manufacturing plants 

were also reported by the Ontario Ministry of Labour in 2002. The 8-hour 

TWA levels ranged from 0.07 to 0.20 ppm in one plant and from 0.08 to 

0.11 ppm in the other. The range of the 15-minute STELs was from 0.15 to 

0.54 ppm and 0.14 to 0.29 ppm, respectively, and for instantaneous ceiling 

limit values, from 0.18 to 7.47 ppm and 0.17 to 0.50 ppm, respectively.
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October 6, 2011

Page H-3

Table H-2. Formaldehyde Exposure Levels for Plywood Manufacture

Authors/Articles Publication

Air 

concentrations of 

Formaldehyde 

Study Population

(Exposed 

Workers) Abstract and Salient Points

Fransman W et al. 

Respiratory 

symptoms and 

occupational 

exposures in New 

Zealand plywood 

mill workers.

Ann Occup 

Hyg. 2003 

Jun;47(4):287-

95. 

0.08 ppm to 0.60 

ppm (0.01 to 0.74 

mg/m3) 

[Geometric mean 

of this range = 

0.06 ppm (0.08 

mg/m3 )]

112 plywood mill 

workers.

Abstract:

OBJECTIVES: To study work exposure and respiratory symptoms in New 

Zealand plywood mill workers. METHODS: Personal inhalable dust (n = 57), 

bacterial endotoxin (n = 20), abietic acid (n = 20), terpene (n = 20) and 

formaldehyde (n = 22) measurements were taken and a respiratory health 

questionnaire was administered to 112 plywood mill workers. RESULTS: 

Twenty-six percent of the dust exposures exceeded 1 mg/m(3); however, none 

of the samples exceeded the legal limit of 5 mg/m(3) [geometric mean (GM) = 

0.7 mg/m(3), geometric standard deviation (GSD) = 1.9]. Workers in the 

composer area (where broken sheets are joined together) were significantly (P 

< 0.01) more highly exposed. Endotoxin levels were low to moderate (GM = 

23.0 EU/m(3), GSD = 2.8). Abietic acid levels ranged from 0.3 to 2.4 micro 

g/m(3) (GM = 0.7 micro g/m(3), GSD = 1.8) and were significantly (P < 0.05) 

higher for workers in the composer area of the process. Geometric mean levels 

of alpha-pinene, beta-pinene and Delta(3)-carene were 1.0 (GSD = 2.7), 1.5 

(GSD = 2.8) and 0.1 (GSD = 1.4), respectively, and alpha-pinene and betapinene levels were significantly (P < 0.001) higher for workers in the 'green 

end' of the process, up to and including the veneer dryers. Formaldehyde levels 

ranged from 0.01 to 0.74 mg/m(3) [GM = 0.08 mg/m(3) (= 0.06 ppm.), GSD = 

3.0]. Asthma symptoms were more common in plywood mill workers (20.5%, 

n = 112) than in the general population [12.8%, n = 415, adjusted OR (95% CI) 

= 1.5 (0.9-2.8)]. Asthma symptoms were associated with duration of 

employment and were reported to lessen or disappear during holidays. No clear 

association with any of the measured exposures was found, with the exception 

of formaldehyde, where workers with high exposure reported more asthma 

symptoms (36.4%) than low exposed workers [7.9%, adjusted OR (95% CI) = 

4.3 (0.7-27.7)]. CONCLUSIONS: Plywood mill workers are exposed to 

inhalable dust, bacterial endotoxin, abietic acid, terpenes and formaldehyde, 

and they appear to have an increased risk of developing work-related 

respiratory symptoms. These symptoms may be due to formaldehyde exposure, 

although a potential causal role for other exposures cannot be excluded.
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October 6, 2011

Page H-4

Table H-2. Formaldehyde Exposure Levels for Plywood Manufacture

Authors/Articles Publication

Air 

concentrations of 

Formaldehyde 

Study Population

(Exposed 

Workers) Abstract and Salient Points

Salient Points:

 Personal measurements for inhalable dust (n = 57), bacterial endotoxin (n = 

20), abietic acid (n = 20), terpene (n = 20) and formaldehyde (n = 22) were 

taken and a respiratory health questionnaire was administered to 112 New

Zealand plywood mill workers.

 Formaldehyde levels ranged from 0.08 ppm to 0.60 ppm (0.01 to 0.74 

mg/m3), the geometric mean of this range was determined to be 0.06 ppm 

(0.08 mg/m3)

 Asthma symptoms were more common in plywood mill workers (20.5%, n = 

112) than in the general population (12.8%, n = 415). No clear association 

with any of the measured exposures was found, with the exception of 

formaldehyde, where workers with high exposure reported more asthma 

symptoms (36.4%) than low exposed workers.

 Plywood mill workers appear to have an increased risk of developing workrelated respiratory symptoms. These symptoms may be due to formaldehyde 

exposure, although a potential causal role for other exposures cannot be 

excluded.

Ballarin C et al. 

Micronucleated 

cells in nasal 

mucosa of 

formaldehydeexposed workers.

Mutat Res. 

1992 Jul; 

280(1):1-7.

0.07-0.08 ppm 

(0.1 mg/m3) in the 

sawmill and 

shearing-press 

departments 

0.32 ppm (0.39 

mg/m3) in the 

warehouse area.

15 nonsmoking 

workers in a 

plywood factory

Abstract:

The frequency of micronuclei (MN) and cytology of respiratory nasal mucosa 

cells were evaluated in 15 nonsmokers exposed to formaldehyde in a plywood 

factory. Each subject was paired with a control matched for age and sex. Mean 

levels of exposure to formaldehyde ranged from about 0.1 mg/m3 in the 

sawmill and shearing-press departments to 0.39 mg/m3in the warehouse area. 

There was a contemporary exposure to low levels of wood dust (inspirable 

mass ranged from 0.23 mg/m3in the warehouse to 0.73 mg/m3during sawing 

operations). Nasal respiratory cell samples were collected by an 

otorhinolaryngologist near the inner turbinate using a brush for endocervical 

cytology. After staining (Feulgen plus Fast Green and Papanicolaou's method 

for MN analysis and cytology, respectively), about 6000 cells were screened 
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page H-5

Table H-2. Formaldehyde Exposure Levels for Plywood Manufacture

Authors/Articles Publication

Air 

concentrations of 

Formaldehyde 

Study Population

(Exposed 

Workers) Abstract and Salient Points

for micronuclei and scored in parallel for cytology according to a 

histopathological scale. A higher frequency of micronucleated cells was 

observed in the exposed group than in the controls (0.90±0.47 vs. 0.25±0.22, 

Mann-Whitney U test: p less than 0.01). Cytological examination indicated 

chronic phlogosis in the nasal respiratory mucosa of plywood factory workers, 

with a high frequency of squamous metaplasia cells (mean score 2.3±0.5 vs. 

1.6±0.5 in the control group, Mann-Whitney U test: p less than 0.01).

Salient Points: 

 The authors examined smears of nasal respiratory mucosa cells sampled 

from the inner turbinate of 15 nonsmokers who were exposed to 

formaldehyde released from a urea-formaldehyde glue used in a plywood 

factory. 

 Estimates of formaldehyde air concentrations ranged from: 0.21 to 0.60 

mg/m3(mean 0.39±0.20 mg/m3) in the warehouse where seven subjects 

worked, 0.08 to 0.14 mg/m3(mean 0.1±0.02 mg/m3) in the shearing press

where six subjects worked, and 0.09 mg/m3(only one sample taken) in the 

sawmill area where two subjects worked. 

 Mean wood dust concentrations for the three areas were 0.23±0.1mg/m3, 

0.41±0.21 mg/m3, and 0.73 mg/m3, respectively. Exposed subjects worked

at the factory for 2 to 19 years (mean 6.8±5.0 years). 

 The authors found a statistically significantly higher percentage of 

micronucleated mucosal cells in the exposed group compared with the 

control group (0.91%±0.47 versus 0.25%±0.22).

Malaka T and 

Kodama AM. 

Respiratory health 

of plywood 

Arch Environ 

Health. 1990 

Sep-Oct; 

45(5):288-94

0.28 ppm to 3.48 

ppm

Average personal 

exposure was 1.13 

186 male plywood 

workers

Abstract:

This study was undertaken to enlarge our understanding of the adverse health 

effects of formaldehyde exposure in the workplace and community 

environment. The respiratory health status of 186 male plywood workers was 

evaluated by spirometric tests, respiratory questionnaires, and chest x-rays. 
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page H-6

Table H-2. Formaldehyde Exposure Levels for Plywood Manufacture

Authors/Articles Publication

Air 

concentrations of 

Formaldehyde 

Study Population

(Exposed 

Workers) Abstract and Salient Points

workers 

occupationally 

exposed to 

formaldehyde.

ppm Area concentrations of formaldehyde were measured in the work environment 

and found to range from 0.28 to 3.48 ppm. The average personal exposure was 

to 1.13 ppm of formaldehyde. Exposure to formaldehyde was associated with 

decrements in the baseline spirometric values (i.e., forced expiratory volume in 

1 sec (FEV1.0), forced expiratory volume/forced vital capacity (FEV/FVC), 

and FEF25%-75%) and with several respiratory symptoms and diseases, 

including cough, phlegm, asthma, chronic bronchitis, and chest colds. The 

results of the study support the hypothesis that chronic exposure to 

formaldehyde induces symptoms and signs of chronic obstructive lung disease.

Salient Points:

 In this cross-sectional study of 186 plywood workers, area concentrations of 

formaldehyde ranged from 0.28 to 3.48 ppm. The average personal exposure 

was 1.13 ppm. 

 Reported average respirable and total wood-dust concentrations in 

workplace air were 0.60 and 1.35 mg/m3, respectively. 

 Exposure was associated with increased complaints of cough, phlegm 

production, asthma, chronic bronchitis and colds. 

 Decrement in FEV1/FVC ratio in exposed subjects compared to controls was 

small but significant, although the authors noted that the clinical significance 

of the differences was unclear. 
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October 6, 2011

Page H-7

Table H-3. Formaldehyde Exposure Levels for Particleboard and Medium-Density Fiberboard Manufacture

(Includes Wood Workers and Oriented Strand Board Manufacture)

Authors/Article Publication

Air concentrations 

of Formaldehyde 

Study Population 

(Exposed Workers) Abstract and Salient Points

The Workers’ 

Compensation Board 

BC (WorkSafeBC)

Discussion Paper –

Occupational 

exposure limit for 

formaldehyde. March 

20, 2007

Not Applicable 0.03-0.032 ppm for 

oriented strand 

board

Workers in a variety 

of industries in 

British Columbia 

including those in 

the plywood, 

particle/fiberboard, 

and oriented strand 

board manufacturing 

facilities.

Abstract: 

None available

Salient Points:

 Sampling data collected by WorkSafeBC over a period of 15 years 

(1990 to 2005) in British Columbia and other locations, including 

Ontario, Quebec, and the Netherlands indicate that worker exposure 

to formaldehyde is likely to occur primarily in the forest panel board 

manufacturing sector (plywood, particle/ fiberboard, oriented 

strand board, laminated wood products manufacturing), resin 

manufacture, acute care hospitals, university and other laboratories, 

and funeral homes.

 Industries in which the current 0.3 ppm 8-hour TWA exposure limit 

(for British Columbia) was exceeded include (range of exposure 

shown):

- Paperboard & cardboard manufacturing (0.04 to 0.38 ppm);

- Laminated wood products manufacturing (0.24 to 0.38 ppm); 

- Pressed/panel particle/fiberboard manufacturing (0.07 to 5.00 

ppm); 

- Oriented strand board manufacturing (0.03 to 0.32 ppm); 

- Funeral homes (none detected to 0.74 ppm); 

- University laboratories (0.52 to 1.15 ppm); 

- Hospitals & medical clinics and laboratories (0.02 to 1.35 

ppm); and 

- Poultry hatcheries (0.1 to 0.35 ppm). 

For other details of this study, as they relate to exposure levels in 

plywood and particle/fiberboard manufacturing, see Table H-1.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page H-8

Table H-3. Formaldehyde Exposure Levels for Particleboard and Medium-Density Fiberboard Manufacture

(Includes Wood Workers and Oriented Strand Board Manufacture)

Authors/Article Publication

Air concentrations 

of Formaldehyde 

Study Population 

(Exposed Workers) Abstract and Salient Points

Lavoue J et al. 2005

Investigation of 

Determinants of Past

and Current 

Exposures to 

Formaldehyde in the 

Reconstituted

Wood Panel Industry 

in Quebec

Annals of 

Occupational 

Hygiene. 2005 

49(7):587-602

Geometric means 

(GMs) of personal 

and area levels 

between 0.1 and 0.4 

ppm for MDF and 

PB.

Highest estimated 

ambient GM 0.43 

ppm in the main 

production area of 

MDF 

manufacturing 

facilities. 

Highest personal 

estimated GM 0.22 

ppm for workers in 

close proximity to 

the press in the PB 

manufacture 

process.

Employees in the 12 

plants (number not 

specified)

Abstract:

OBJECTIVES: Past and present formaldehyde measurements made in 

facilities manufacturing reconstituted wood panels in Quebec have 

been collected to assess formaldehyde exposure and its determinants in 

this industry.

METHODS: All 12 plants manufacturing OSB, MDF, and PB in 

Quebec were visited by a research team which took area and personal 

measurements. Past measurements taken by governmental 

occupational health teams in these plants were also collected. Logtransformed formaldehyde concentrations were analyzed with extended 

linear mixed-effects models.

RESULTS: During 2001–2002, 275 measurements were taken by the 

research team, while 590 measurements dating back to 1984 were 

collected from governmental files. The area measurements had a global 

GM of 0.28 ppm [geometric standard deviation (GSD): 3.1]. The GM 

of the personal measurements was 0.17 ppm (GSD: 2.3). The fixedeffects of the models for personal and area measurements explained 61 

and 57% of the variance, respectively. Job (working area for area 

concentrations), process (PB, MDF, OSB), season of sampling, origin 

of the data (research, governmental) and year of sampling were 

significant determinants of exposure. Proximity to the press, winter 

conditions, PB and MDF processes and governmental data resulted in 

the highest exposures. Significant within-sampling campaign 

correlation was found for both personal and area models. The final 

models include different residual variances by process for personal 

measurements and by working area for area measurements.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page H-9

Table H-3. Formaldehyde Exposure Levels for Particleboard and Medium-Density Fiberboard Manufacture

(Includes Wood Workers and Oriented Strand Board Manufacture)

Authors/Article Publication

Air concentrations 

of Formaldehyde 

Study Population 

(Exposed Workers) Abstract and Salient Points

CONCLUSIONS: Several determinants of exposure to formaldehyde 

in the reconstituted wood panel industry were successfully identified. 

Higher levels found in governmental data as compared to research data 

may be explained by a ‘worst-case’ strategy bias. The observed intrasampling campaign correlation supports existing results suggesting that 

measurements taken in a small time frame tend to be correlated. 

Exposures in this sector are low compared to the 8-hour TWA OELs of 

most Canadian jurisdictions (e.g., 0.75 ppm) but close to the most 

demanding ones (e.g., 0.3 ppm, as for British Columbia).

Salient Points:

 Twelve plants manufacturing OSB, MDF, and PB in Quebec were 

visited from June 2001 to March 2002. The visits were conducted 

by a team of 2–4 industrial hygienists and technicians and lasted 1 

to 2 days.

 The research team took area and personal measurements. Past 

measurements taken by governmental occupational health teams in 

these plants were also collected. The visits performed by the 

research team yielded 275 measurements while 590 measurements 

were available from governmental files.

 Exposures to formaldehyde in the OSB manufacturing industry were 

mostly below 0.1 ppm with some work zones/jobs associated with 

somewhat higher levels according to the governmental data. 

 Formaldehyde exposure levels in the MDF and PB manufacturing 

industries were similar, with observed and estimated GMs of 

personal and area levels between 0.1 and 0.4 ppm depending on the 

source of data. The highest estimated ambient GM was 0.43 ppm in 

the main production area of MDF manufacturing facilities (this 

estimate is increased to 1.28 ppm when governmental data are 

used). The highest personal estimated GM is 0.22 ppm for workers 

in close proximity to the press in the PB manufacture process (this 

estimate is increased to 0.62 ppm if the governmental data are 

considered).
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October 6, 2011

Page H-10

Table H-3. Formaldehyde Exposure Levels for Particleboard and Medium-Density Fiberboard Manufacture

(Includes Wood Workers and Oriented Strand Board Manufacture)

Authors/Article Publication

Air concentrations 

of Formaldehyde 

Study Population 

(Exposed Workers) Abstract and Salient Points

 Governmental measurements were consistently found higher than 

those measured by the research team, pointing to the probable 

existence of a ‘worst-case’ bias in governmental data.

 Area measurements were consistently higher than personal 

measurements. This is consistent with the fact that the most exposed 

workers are those who spend the most time in the production area 

unprotected by ventilated booths. While none of the personal 

measurements in this study was greater than 2 ppm, 4% and 6% of 

the research and governmental ambient concentrations, respectively, 

were greater than this value.

 Although the results of this study point to generally low personal 

full-shift exposure to formaldehyde in the industrial sector studied, 

the potential for short-term high exposures associated with specific 

and occasional tasks cannot be ruled out on the basis of our study.

 Levels reported prior to 1985 are consistently higher than those in 

this study database. According to the authors, this maybe explained 

by the generalized use, around 1985, of low formaldehyde emission 

resins.

 The measured and estimated TWA levels of exposure to 

formaldehyde in this sector can be considered low compared to the 8 

hour TWA OELs of most Canadian jurisdictions (e.g. 0.75 ppm) but 

close to the most demanding ones (e.g., 0.3 ppm, as for British 

Columbia).
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page H-11

Table H-3. Formaldehyde Exposure Levels for Particleboard and Medium-Density Fiberboard Manufacture

(Includes Wood Workers and Oriented Strand Board Manufacture)

Authors/Article Publication

Air concentrations 

of Formaldehyde 

Study Population 

(Exposed Workers) Abstract and Salient Points

Chung KY et al.

A study on dust 

emission, particle 

size distribution and 

formaldehyde 

concentration during 

machining of MDF.

Ann Occup Hyg. 

2000 Sep; 44(6): 

455-66. 

Less than 0.14 ppm 

(0.17mg/m3)

N/A Abstract:

A study to characterize the quantity, particle size distribution, and 

morphology of dust created during the machining of MDF was carried 

out. Four different types of MDF boards were included in this study, 

including a 'zero-formaldehyde' board that contains isocyanate-based 

resin, rather than urea-formaldehyde resin. In addition, natural 

softwood (pine) and natural hardwood (oak) were included in the 

study, for comparison with MDF. The results show that in general, the 

dust generated by machining MDF is comparable in terms of particle 

size distribution and morphology with the dust generated by similarly 

machining hardwood or softwood. The quantity of dust generated 

during sanding is higher for sanding MDF compared with sanding 

either hardwood or softwood. However, for sawing, there is no 

significant difference between MDF and natural woods, in terms of the 

quantity of dust generated. Free formaldehyde in the air was less than 

0.17mg/m3during machining of the Class B (higher formaldehyde 

potential) MDF board. There was no measurable isocyanate in the dust 

generated from the boards.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page H-12

Table H-3. Formaldehyde Exposure Levels for Particleboard and Medium-Density Fiberboard Manufacture

(Includes Wood Workers and Oriented Strand Board Manufacture)

Authors/Article Publication

Air concentrations 

of Formaldehyde 

Study Population 

(Exposed Workers) Abstract and Salient Points

Herbert FA et al.

Respiratory 

consequences of 

exposure to wood 

dust and 

formaldehyde of 

workers 

manufacturing 

oriented strand 

board.

Arch Environ 

Health. 1994 

Nov-Dec; 

49(6):465-70.

Up to 0.27 ppm 99 workers 

employed in the 

manufacture of 

oriented strand 

board.

Abstract:

A cross-sectional study was performed at a plant in which 99 workers 

were employed in the manufacture of oriented strand board. This group 

was compared with 165 unexposed workers from the petroleum 

industry. Both groups were assessed, using a questionnaire, spirometry, 

and skin prick tests to common environmental antigens. Environmental 

studies showed a low dust level of 0.27 mg/m3, consisting of particles 

of a mass median aerodynamic equivalent diameter of 2.5 microns. 

There were parameter concentrations of formaldehyde, up to 0.27 ppm. 

A significant difference between the oriented strand board workers and 

oil field workers was noted for the forced expiratory volume in 

1s/forced vital capacity ratio, without significant differences in either 

the forced expiratory volume in 1 s or the forced vital capacity. 

Oriented strand board workers who were current smokers were three 

times as likely to have a forced expiratory volume in 1s/forced vital 

capacity ratio of less than 75% of that found in the currently smoking 

oil field workers. Significant reductions in forced expiratory volume in 

1s (p = .044) and forced vital capacity (p = .022) in oriented strand 

board workers were noted across the work shift. The oriented strand 

board workers complained of self-reported asthma and of lower 

respiratory tract symptoms significantly more frequently than did oil 

workers for all of the symptoms examined. The prevalence of atopy 

was not different in the two groups. Lung function was significantly 

better in oriented strand board workers who had no symptoms, 

compared with oriented strand board workers who were symptomatic. 

(ABSTRACT TRUNCATED AT 250 WORDS)

Salient Points: 

 In this cross-sectional study, 99 workers employed in the 

manufacture of oriented strand board were compared with 165 

unexposed workers from the petroleum industry.
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October 6, 2011

Page H-13

Table H-3. Formaldehyde Exposure Levels for Particleboard and Medium-Density Fiberboard Manufacture

(Includes Wood Workers and Oriented Strand Board Manufacture)

Authors/Article Publication

Air concentrations 

of Formaldehyde 

Study Population 

(Exposed Workers) Abstract and Salient Points

 Parameter concentrations of formaldehyde, up to 0.27 ppm, were 

noted.

 Environmental studies showed a low dust level of 0.27mg/m3, 

consisting of particles of a mass median aerodynamic equivalent 

diameter of 2.5 microns.

 Significant reductions in forced expiratory volume and forced vital 

capacity were noted across the work shift in oriented strand board 

workers. 

 Oriented strand board workers complained of self-reported asthma 

and of lower respiratory tract symptoms significantly more 

frequently than did oil workers for all of the symptoms examined.

Edling C et al.

Occupational 

exposure to 

formaldehyde and 

histopathological 

changes in the nasal 

mucosa.

Br J Ind Med. 

1988 Nov; 

45(11):761-5.

0.08 to 0.9 ppm. 

(midpoint of this 

range is 0.49 ppm). 

Peaks of up to 4.1 

ppm were measured 

during the 8-year 

period

75 workers from two 

particle board 

processing plants 

and a laminate plant

Abstract:

To study the cytotoxic effect of formaldehyde on the human nasal 

mucosa, 75 men with occupational exposure to formaldehyde or to 

formaldehyde and wood dust were examined, looking particularly at 

early signs of irritative effects and histopathological changes in the 

nasal mucosa. All men underwent a medical examination, and a nasal 

biopsy specimen was examined by a pathologist and graded from 0-8 

according to the morphological changes. A high frequency of nasal 

symptoms, mostly a running nose and crusting, was related to exposure 

to formaldehyde. Only three men had a normal mucosa; the remainder 

had loss of cilia and goblet cell hyperplasia (11%) and squamous 

metaplasia (78%); in six cases (8%) there was a mild dysplasia. The 

histological grading showed a significantly higher score when 

compared with unexposed contents (2.9 v 1.8). There was no dose 

response relation, no malignancies, and no difference in the 

histological score between those exposed to formaldehyde or to 

formaldehyde and wood dust.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page H-14

Table H-3. Formaldehyde Exposure Levels for Particleboard and Medium-Density Fiberboard Manufacture

(Includes Wood Workers and Oriented Strand Board Manufacture)

Authors/Article Publication

Air concentrations 

of Formaldehyde 

Study Population 

(Exposed Workers) Abstract and Salient Points

Salient Points:

 Measurements taken by in-house hygienists during an 8-year period 

before the study (between 1975 and 1983) were in the range 0.08 to 

0.9 ppm with peaks reaching 4.07 ppm. A mean TWA concentration 

was not reported, but the midpoint of this range is 0.49 ppm. Air 

concentrations were qualitatively assessed as being “somewhat 

higher” during earlier periods. 

 Wood dust air concentrations in the particle board plants ranged 

from 0.6 to 1.1 mg/m3; air in the laminate plant was reported to be 

without wood dust. 

 Employment durations ranged from 1 to 39 years with a mean of 

10.5 years. 

 Runny nose, nasal crusting, and runny eyes when at work were 

reported by 60 and 75% of the exposed subjects, respectively. Gross 

clinical examination showed that 25% of exposed workers had 

either swollen nasal mucosa or dry nasal mucosa. 

 The authors reported that the average histological score for the 

exposed group (2.8) was statistically significantly greater than the 

control score (1.8) and that there was no difference in average 

histological scores between the exposed workers from the particle 

board plants, where confounding exposure to wood dust occurred, 

and those from the laminate plant (without wood dust exposure). 

This observation supports the hypothesis that the observed nasal

epithelial lesions were caused by formaldehyde and not by an 

interaction between formaldehyde and wood dust.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page H-15

Table H-3. Formaldehyde Exposure Levels for Particleboard and Medium-Density Fiberboard Manufacture

(Includes Wood Workers and Oriented Strand Board Manufacture)

Authors/Article Publication

Air concentrations 

of Formaldehyde 

Study Population 

(Exposed Workers) Abstract and Salient Points

Horvath EP et al. 

1988. 

Effects of 

formaldehyde on the 

mucous membranes 

and lungs: A study of 

an industrial 

population.

JAMA. 1988 Feb 

5; 259(5):701-7.

0.17 to 2.93 ppm 

(mean of 0.69 ppm)

109 workers in a 

particle board and 

molded plastics 

plant

Abstract:

One hundred nine workers and 254 control subjects were studied to 

evaluate the effects of formaldehyde on the mucous membranes and 

lungs. A modified, respiratory symptom questionnaire and spirometry 

were administered to all study participants before and after their work 

shift, and formaldehyde levels were determined for each test subject. 

Over the course of the monitored work shift, test subjects demonstrated 

a dose-dependent excess of irritant symptoms and a statistically 

significant decline in certain lung function parameters. Analysis of test 

and control subject data combined revealed a correlation between 

formaldehyde exposure and these pulmonary changes. Baseline 

spirometry values were not significantly different between test and 

control groups, and formaldehyde-exposed workers did not report an 

excess of respiratory symptoms. Formaldehyde is a dose-dependent 

irritant of the eyes and mucous membranes at low-level exposures. It 

can exert a small, across-shift effect on airways but after a mean 

exposure of 10 years does not appear to cause permanent respiratory 

impairment.

Salient Points:

 The duration of exposure among exposed workers ranged from <1 

year to 20 years, with a mean and median of 10.3 and 10 years, 

respectively.

 Estimates of formaldehyde air concentrations ranged from 0.17 to 

2.93 ppm with a mean of 0.69 ppm. Nuisance particles 

(predominantly softwood dust) were also detected in the particle 

board area. 
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October 6, 2011

Page H-16

Table H-3. Formaldehyde Exposure Levels for Particleboard and Medium-Density Fiberboard Manufacture

(Includes Wood Workers and Oriented Strand Board Manufacture)

Authors/Article Publication

Air concentrations 

of Formaldehyde 

Study Population 

(Exposed Workers) Abstract and Salient Points

 The percentages of particle board workers reporting a number of 

symptoms of respiratory irritation over a work shift were 

statistically significantly greater than work shift reporting 

percentages for a nonexposed group of 264 food-processing 

workers: cough (34.9 versus 18.9%), chest pains (9.2 versus 2%), 

phlegm production (26.6 versus 9.8%),burning nose (28.4 versus 

2%), stuffy nose (33.9 versus 14.2%), burning or watering eyes 

(39.5 versus 9.1%), itchy nose (21.1 versus 7.9%), and sore/burning 

throat (22 versus 3.9%).

 The authors concluded that the effects noted were possibly not only 

due to formaldehyde alone but could also be attributed to the 

presence of respirable particles of wood dust.

Kauppinen TP and 

Niemelä RI

Occupational 

exposure to chemical 

agents in the 

particleboard 

industry.

Scand J Work 

Environ Health. 

1985 Oct; 

11(5):357-63.

Before 1975, 

greater than 2 ppm 

during many work 

phases.

Means below 2 

ppm during most 

work phases during 

1975 and 1984.

For area 

measurements, 

means between 0.4 

ppm and 2.3 ppm 

(depending on 

individual locations 

in the plant).

Not available Abstract:

Most of the measurements concerned formaldehyde and wood dust. 

The other substances measured included terpenes, solvents, and 

heptachlor. Before 1975, the formaldehyde concentration regularly 

exceeded 2 ppm during many work phases. Considerable 

improvements in ventilation and the composition of glues have 

occurred since then, and today the exposure level is below 2 ppm 

during most work phases. High peak concentrations, 20 to 30 ppm at 

the highest, were characteristic of exposure in earlier years. The 

concentrations of wood dust have also decreased (e.g., from over 5 

mg/m3to 1 mg/m3or below during forming). These data have been 

used to evaluate past exposures in an epidemiologic study on cancer 

risks in the particleboard, plywood, and sawmill industries.
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October 6, 2011

Page H-17

Table H-3. Formaldehyde Exposure Levels for Particleboard and Medium-Density Fiberboard Manufacture

(Includes Wood Workers and Oriented Strand Board Manufacture)

Authors/Article Publication

Air concentrations 

of Formaldehyde 

Study Population 

(Exposed Workers) Abstract and Salient Points

Alexandersson R et 

al.

Exposure to 

formaldehyde: 

Effects on pulmonary 

function.

Arch Environ 

Health. 1982 

Sep-Oct; 

37(5):279-84.

0.37 ppm (0.45 

mg/m3)

47 woodworkers Abstract:

Forty-seven subjects exposed to formaldehyde (mean air concentration 

0.45 mg/m3) and 20 unexposed subjects, all of whom were employed 

at a carpentry shop, were studied with regard to symptoms and 

pulmonary function. Symptoms involving eyes and throat irritation as 

well as chest oppression were significantly more common in the 

exposed subjects than in the unexposed controls. Spirometry and single 

breath nitrogen washout were normal Monday morning before 

exposure to formaldehyde. A reduction in forced expiratory volume in 

1 sec by an average of 0.2 L (P = 0.002), percent forced expiratory 

volume by 2% (P = 0.04), maximum midexpiratory flow by 0.3 L/sec 

(P = 0.04), and an increase in closing volume in percentage of vital 

capacity by 3.4% (P - 0.002) were seen after a day of work and 

exposure to formaldehyde, suggesting bronchoconstriction. Smokers 

and nonsmokers displayed similar changes in spirometry and nitrogen 

washout.
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Appendix I

MODEL RESULTS FOR INDOOR AIR CONCENTRATIONS AT CWP FABRICATION 

SITES USING PRE-BASELINE EMISSION RATES
Formaldehyde Occupational Exposure Assessment Report - Draft Final Report

October 6, 2011

Page I-1

Table I-1. Results for the Calculation Trials for the What-If Low- and High-End Pre-Baseline Indoor Air Concentrations

Varied Parameter

Calculated Concentration for Pre-Baseline, ppm

Intermediate 4 Low End 5 High End 6

HWPW PB MDF HWPW PB MDF HWPW PB MDF

Vary Emitting Surface Area 1

0.019 0.024 0.044

0.006 0.007 0.009 0.142 0.197 0.399

Vary Effective Ventilation 

Rate 2 0.007 0.008 0.011 0.414 0.580 1.186

Vary Emission Rate 30.012 0.018 0.018 0.022 0.044 0.090

1

For area, the intermediate value is based on the aggregate average per-site throughput calculated using domestic composite wood product consumption data from the 

EPA market profile. The high-end and low-end values are calculated assuming 1,000% and 10% of the aggregate average throughput, respectively.

2 Effective ventilation is varied based on values shown in Table 3-3. The low-end, typical, and high-end values are 50, 1,500 and 10,000 cfm, respectively.

3 Emission rate is varied based on values shown in Table 3-4.

4

Intermediate concentration is calculated using intermediate value for surface area, typical value for effective ventilation rate, and weighted-average pre-baseline 

emission rate for each CWP type.

5 Low-end values calculated according to Table 3-2.

6 High-end values calculated according to Table 3-2.

Table I-2. Combined (for All CWP) Results: Estimated Range of Values for the What-If Low- and High-End Indoor Air 

Concentrations for Pre-Baseline

Case Intermediate (ppm) Low End (ppm) High End (ppm)

Pre-Baseline 0.019 – 0.044 0.006 – 0.018 0.022 – 1.186