Draft Final 

Occupational and Consumer Exposure and 

Environmental Release Assessment of 

Formaldehyde in Urea-Formaldehyde Resin 

Manufacture and of Certain Chemicals for 

Substitute Technologies to Reduce 

Emissions from Composite Wood Products 

U.S. Environmental Protection Agency

Office of Pollution Prevention and Toxics

Chemical Engineering Branch and Exposure Assessment Branch 

 1200 Pennsylvania Avenue NW 

 Washington, DC 20460 

Draft Deliberative – Do not cite or quote - October 2011 
i

Executive Summary 

This assessment was conducted to support a rulemaking under the Toxic Substances 

Control Act (TSCA) Title VI, which includes examining substitute technologies to reduce 

formaldehyde emissions from composite wood products (CWPs). The scope of the assessment 

includes occupational exposures to and environmental releases of formaldehyde in ureaformaldehyde (UF) resin manufacture and of some chemicals in substitute technologies intended 

to reduce formaldehyde emissions from CWPs throughout their life cycle. Inclusion in this life 

cycle is the end product usage by commercial workers and consumers, such as home hobbyists 

and building/home occupants who may be exposed during and after product installation. . This 

report will refer to these chemicals as “substitute chemicals” or “substitutes”. For the purpose of 

this assessment, CWPs include hardwood plywood (HWPW), medium-density fiberboard 

(MDF), and particleboard (PB). The life cycle stages analyzed in this report include resin 

manufacturing, CWP manufacturing, downstream product manufacturing, and commercial/ 

consumer use. 

The scope of this assessment, presented in Section 2.0, includes substitute chemicals with 

toxic effects ranging from medium to high depending on the endpoint. Substitutes include 

monomers of resins that are alternatives to urea-formaldehyde (UF) resins, additives to UF and 

alternate resins, and treatment chemicals. 

Inhalation exposure monitoring data for the substitute chemicals and exposure scenarios 

in the scope of work were obtained from OSHA’s Integrated Management Information System 

(IMIS), European Union (EU) Risk Assessments, and other chemical-specific monitoring 

studies. These monitoring data were used to assess exposures to formaldehyde and the substitute 

chemicals during relevant stages in the CWP life cycle. Where data were not available, OSHA 

Permissible Exposure Limits (PELs) were used to estimate “what-if” type inhalation exposures. 

Dermal exposures were primarily determined using standard EPA models. The exposure 

assessment results are summarized in Table ES-1, while discussions for each industrial and 

commercial/ consumer sector are provided in the report. A discussion of the occupational 

assessment methods is presented in Section 3.0. This report was developed in advance of a 

hazard report for the substitutes, so inhalation and dermal exposures were assessed regardless of 

potential toxic effects (e.g., cancer or non-cancer). 

Daily inhalation exposure concentrations and dermal exposures, expressed as potential 

doses, are generally highest in the preliminary life cycle stages in which the substitute chemicals 

are introduced (primarily resin manufacture) and generally are expected to decrease throughout 

subsequent life cycle stages as the substitutes are reacted, immobilized in resin matrices, 

volatilized, or reduced to very low concentrations. An exception to this general expectation is 

where inhalation concentrations of several of the volatile chemicals increase in the CWP 

manufacturing stage as compared to the resin manufacturing stage. 

The daily worker exposure inhalation concentrations generated in this report are highly 

uncertain and present significant limitations for their use. The air concentration parameters used 

to estimate the associated daily exposure concentrations come from a variety of sources, and 

their representativeness of actual air concentrations in workplaces in the CWP life cycle chain is 

not known. The daily exposure concentrations are most suitable for a qualitative overview of 

worker exposure issues and identification of data gaps. 
ii

Inhalation monitoring data were generally sparse, and it is uncertain whether these data 

sets may represent exposures to substitute chemicals in the various CWP life cycle stages in the 

U.S. The characterizations of inhalation concentrations (e.g., average, 95th percentile, single 

point value, assumed high-end) were not consistent among the substitute chemicals. 

These uncertainties and limitations, as related to worker inhalation exposures in this 

report, indicate that direct quantitative comparison between various chemicals and life cycle 

stages is likely to be imprecise and is not recommended. 

 A preliminary data search for releases of substitute chemicals was commenced for this 

report using one primary source. EPA then determined that releases would not be used for other 

EPA analyses, so no further data searches or analyses were conducted. This report presents the 

preliminary data search approach and data found for informational purposes only. 

Table ES-2 presents a summary of release data found for each chemical and life cycle 

stage. Release data were obtained from the Toxic Release Inventory (TRI), which is the main 

literature source for release data and is described in Section 4.0. These data only include 

quantities that are released or transferred off site for treatment in wastewater or incineration 

units, in quantities greater than 25,000 pounds in specific regulated sectors. These data do not 

include facilities generating less than 25,000 pounds of each chemical or employing less than 10 

full-time employees, chemicals not subject to the TRI (of the substitute chemicals, only 

melamine is not subject to TRI reporting), chemicals manufactured in a sector not regulated by 

TRI, or quantities sent to on- and off-site waste management such as recycling and reuse. These 

release data are not analyzed and are presented for informational purposes only. 

Section 5.0 of this assessment presents an uncertainty analysis. Section 6.0 presents 

information and data related to facilities and workers in the CWP lifecycle. Section 7.0 presents 

exposure and release data and estimates for the substitutes during the lifecycle steps. Section 8.0 

summarizes the data gaps, uncertainties, and limitations of this work. 
iii

Table ES-1. Summary of Estimated Average Inhalation Concentrations and Dermal 

Potential Doses for Assessed Chemicals by Life Cycle Stage 

Formaldehyde 

and Substitute 

Chemicals Life Cycle Stage 

Average Daily 

Concentration 

(μg/m3) 

Lifetime 

Average Daily 

Concentration 

(μg/m3) 

Dermal Potential 

Dose 

(mg/kg/day)a

Formaldehyde UF Resin Manufacturing 18 10 <0.15 

Methanol UF Resin Manufacturing 7,300c 4,200c Not estimatedg

CWP Manufacturing 59,000b 34,000b Not estimatedg 

Downstream Product Manufacturing Negligiblef Negligiblef Not quantifiableh

Commercial/ Consumer Use Negligiblef Negligiblef Not quantifiableh

Melamine MUF and Other Melamine-Based 

Resin Manufacturing 

23-260 13-150 <44 

CWP Manufacturing Negligiblef Negligiblef <7.6 

Downstream Product Manufacture Negligiblef Negligiblef Not quantifiableh

Commercial/ Consumer Use Negligiblef Negligiblef Not quantifiableh

Epichlorohydrin Polyamine Epichlorohydrin 

Manufacturing 

170 99 Not estimatedg 

PureBond Manufacturing Negligiblef Negligiblef Not quantifiableh

CWP Manufacturing (HWPW) Negligiblef Negligiblef Not quantifiableh

Downstream Product Manufacturing Negligiblef Negligiblef Not quantifiableh

Commercial/ Consumer Use Negligiblef Negligiblef Not quantifiableh

Polymethylene 

Diphenyl 

Diisocyanate 

pMDI Resin Manufacturing 2.3-46 1.3-26 <25 

CWP Manufacturing (PB and MDF) 3.4 2.0 <25 

Downstream Product Manufacturing Negligiblef Negligiblef Not quantifiableh

Commercial/ Consumer Use Negligiblef Negligiblef Not quantifiableh

Vinyl Acetate 

Monomer 

PVA Resin Manufacturing 16-11,000 9.1-6,000 Not estimatedg 

CWP Manufacturing (HWPW) Negligiblef Negligiblef Not estimatedg 

Downstream Product Manufacturing Negligiblef Negligiblef Not quantifiableh

Commercial/ Consumer Use Negligiblef Negligiblef Not quantifiableh

Chromium (III) Addition of Chromium(III) Salts to 

PVA Resin Negligiblef

 Negligiblef <25 

CWP Manufacturing Negligiblef Negligiblef <2.5 

Downstream Product Manufacturing Negligiblef Negligiblef Not quantifiableh

Commercial/ Consumer Use Negligiblef

 Negligiblef Not quantifiableh

Ammonia CWP Manufacturing 8,000b 4,600b Not quantifiablei

Downstream Product Manufacturing Negligiblef Negligiblef Negligiblej

Commercial/ Consumer Use Negligible Negligiblef Negligiblej

Phenol PF Resin Manufacturing <9.4-270d <5.3-160d <3.8 

CWP Manufacturing <230-460d <130-260 e <<<3.8 

Downstream Product Manufacturing Negligiblef Negligiblef Not quantifiableh

Commercial/ Consumer Use Negligiblef Negligiblef Not quantifiableh

μg/m3 – micrograms per cubic meter 

mg/kg/day – milligrams per kilogram (body weight) per day 

UF – Urea-formaldehyde 

PF – Phenol-formaldehyde 

MUF – Melamine-urea-formaldehyde 

CWP – Composite wood product 
iv

PB – Particleboard 

MDF – Medium density fiberboard 

HWPW – Hardwood plywood 

pMDI - polymethylene diphenyl diisocyanate 

PVA – Polyvinyl acetate 

a – Based on EPA/OPPT dermal models (see Section 3.2.2) 

b – No data available – results based on “what-if” concentrations at the OSHA Permissible Exposure Limit (PEL) 

level. 

c – 95th percentile value. 

d – Monitoring data reported minimum concentrations as zero. For this assessment, minimum concentrations were 

assumed to be equal to the limit of detection for phenol, as specified in OSHA Analytical Method No. 32. 

e – 50th to 90th percentile range.

f – Negligible inhalation exposures are defined as < 0.01 mg/m3 TWA. g – The dermal model used for estimates in this report could not be adjusted to account for the higher volatility of 

formaldehyde, methanol, epichlorohydrin, and vinyl acetate when the chemical is expected to be handled in nearly 

pure forms or in highly concentrated and volatile mixtures. See Section 3.2.2 for an explanation. 

h – Some surface contact with solids containing the chemical may occur (similar to cast solids as indicated in 

Section 3.2.2, Table 3-2). 

i – Dermal exposures to gases are not quantifiable. See Section 3.2.2 for an explanation. 

j – Ammonia is expected to be volatilized during CWP curing and not present during downstream product 

manufacturing and commercial/ consumer (e.g., home hobbyists, home occupants, etc.) use. 
v

Table ES-2. Summary of Releases of Formaldehyde and Substitute Chemicals by Life Cycle Stage as Reported in T

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) Off-Site Transfers for Release (lb) 

Stack 

Air 

Fugitive 

Air Total Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

FORMALDEHYDE 

UF Resin Manufacturing 

325211 

(64 sites) 

Plastics Material and Resin Mfg 205,136 44,885 250,021 7,687 289,757 547,465 117,780 13,984 131,764 

METHANOL 

UF Resin Manufacturing 

325211 

(111 sites) 

Plastics Material and Resin Mfg 1,824,256 1,622,898 3,447,155 54,452 1,748,854 5,250,461 2,835,660 46,413 2,882,073 

CWP Manufacturing 

321211 

(2 sites) 

Hardwood Veneer and Plywood Mfg 43,449 6,332 49,781 0 0 49,781 0 0 0 

321219 

(73 sites) 

Reconstituted Wood Product Mfg 4,542,783 103,440 4,646,223 390 18 4,646,631 565 0 565 

EPICHLOROHYDRIN 

Polyamine Epichlorohydrin / PureBond Manufacturing 

325211 

(13 sites) 

Plastics Material and Resin Mfg 9,086 58,957 68,043 1,413 199 69,655 1 0 1 

325998 

 (13 sites) 

All Other Misc. Chem. Product and Preparation Mfg 2,000 7,419 9,419 0 429,734 439,153 66 69 135 

DIISOCYANATE CATEGORY (includes MDI)

pMDI Resin Manufacturing

325211 

(68 sites) 

Plastics Material and Resin Mfg 858 2,936 3,793 0 25 3,818 44,551 58,338 102,889 

CWP Manufacturing 

321219 

(30 sites) 

Reconstituted Wood Product Mfg 7,789 1,236 9,025 0 0 9,025 0 0 0 
vi

Table ES-2. Summary of Releases of Formaldehyde and Substitute Chemicals by Life Cycle Stage as Reported in T

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) Off-Site Transfers for Release (lb) 

Stack 

Air 

Fugitive 

Air Total Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

Downstream Product Manufacturing 

321911 

(8 sites) 

Wood Window and Door Mfg 0 5 5 0 0 5 0 0 0 

321918 

(1 site) 

Other Millwork (including Flooring) 0 0 0 0 0 0 0 0 

321991 

(63 sites) 

Manufactured Home (Mobile Home) Mfg 0 0 0 0 0 0 0 57 57 

321992 

(2 sites) 

Prefabricated Wood Building Mfg 0 0 0 0 0 0 0 0 

337211 

(4 sites) 

Wood Office Furniture Mfg 0 0 0 0 0 0 0 0 

337212 

(1 site) 

Custom Architectural Woodwork and Millwork Mfg 0 23 23 0 0 23 0 0 0 

337122 

(1 site) 

Nonupholstered Wood Household Furniture Mfg 0 0 0 0 0 0 0 0 0 

337127 

(2 sites) 

Institutional Furniture Mfg 0 13 13 0 0 13 0 0 0 

VINYL ACETATE MONOMER 

PVA Resin Manufacturing 

325211 

(43 sites) 

Plastics Material and Resin Mfg 297,366 355,341 652,707 18 54 652,779 2,655 0 2,655 

CHROMIUM 

Addition of Cr (III) salts to PVA resin 

325211 

(3 sites) 

Plastics Material and Resin Mfg 9 250 259 0 70 329 14 186 200 
vii

Table ES-2. Summary of Releases of Formaldehyde and Substitute Chemicals by Life Cycle Stage as Reported in T

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) Off-Site Transfers for Release (lb) 

Stack 

Air 

Fugitive 

Air Total Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

Downstream Product Manufacturing 

337127 

(4 sites) 

Institutional Furniture Mfg 5 255 260 0 0 260 501 0 501 

337212 

(3 sites) 

Custom Architectural Woodwork and Millwork Mfg 0 2 2 0 0 2 182 72 254 

337215 

(4 sites) 

Showcase, Partition, Shelving, and Locker Mfg 0 250 250 1 0 251 0 0 0 

CHROMIUM COMPOUNDS 

Addition of Cr (III) salts to PVA resin 

325211 

(10 sites) 

Plastics Material and Resin Mfg 605 392 997 13,000 407,379 421,376 77,901 322 78,223 

Downstream Product Manufacturing 

321911 

(2 sites) 

Wood Window and Door Mfg 22 0 22 0 0 22 826 7,191 8,017 

337127 

(1 site) 

Institutional Furniture Mfg 6 4 10 0 0 10 0 0 0 

AMMONIA 

CWP Manufacturing 

321211 

(1 site) 

Hardwood Veneer and Plywood Mfg 0 5 5 0 0 5 0 0 0 

321219 

(7 sites) 

Reconstituted Wood Product Mfg 272,885 1,285 274,170 1,295 751 276,216 314 0 314 

PHENOL 

Resin Manufacturing

325211 

(52 sites) 

Plastics Material and Resin Mfg 139,001 137,432 276,433 2,149 286 278,868 826,294 167,525 993,819 

CWP Manufacturing 

321219 

(10 sites)

Reconstituted Wood Product Mfg 305,814 2,472 308,286 21 155 308,462 57 0 57 
viii

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 an

December 2009. These data only include quantities that are released or transferred off site for treatment in wastewater and incineration quantities sent to on- and off-site waste management such as recycling and reuse. a - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). 
TABLE OF CONTENTS

Page 

EXECUTIVE SUMMARY .................................................................................................................... I

LIST OF FIGURES .......................................................................................................................... XII

LIST OF TABLES .......................................................................................................................... XIII

1.0 INTRODUCTION AND PURPOSE ........................................................................................... 1

2.0 SCOPE OF THE ASSESSMENT .............................................................................................. 1

2.1 Life Cycle Stages .................................................................................................... 2

2.1.1 Resin Manufacturing ................................................................................... 3

2.1.2 Composite Wood Product (CWP) Manufacturing (Primary Manufacturing)

 3

2.1.3 Downstream Product Manufacturing .......................................................... 3

2.1.4 Commercial/ Consumer Use ....................................................................... 3

2.2 NAICS Codes Associated with Life Cycle Stages ................................................. 4

3.0 OCCUPATIONAL EXPOSURE ASSESSMENT METHOD ......................................................... 6

3.1 Data Collection ....................................................................................................... 6

3.1.1 OSHA IMIS Data ........................................................................................ 6

3.1.2 International Reports and Assessments ...................................................... 7

3.2 Approach for Assessing Occupational Exposures .................................................. 7

3.2.1 Inhalation Exposures ................................................................................... 7

3.2.2 Dermal Exposures ....................................................................................... 8

3.3         Approach for Assessing Consumer Exposures..................................................... 12

4.0 RELEASE DATA COLLECTION AND PRESENTATION ........................................................ 12

5.0 LIMITATIONS OF ASSESSMENT METHOD AND UNCERTAINTY ASSOCIATED WITH 

RESULTS ....................................................................................................................................... 13

5.1.1 Amount of Exposure Data Available ........................................................ 13

5.1.2 Applicability of Exposure or Release Data ............................................... 14

5.1.3 Representativeness of Monitoring Data and Models ................................ 14

5.1.4 Sources of Exposure ................................................................................. 14

5.1.5 Frequency and Duration of Exposure ....................................................... 15

5.1.6 Number of Sites and Workers ................................................................... 15

5.1.7 Post-CARB Rule Exposures ..................................................................... 15

6.0 GENERAL PROCESS DESCRIPTIONS AND FACILITY ESTIMATES ..................................... 16

6.1 Resin Manufacturing ............................................................................................. 16

6.1.1 General Resin Manufacturing Process ...................................................... 17

6.1.2 Number of Establishments, Workers, Production Hours, and Work Day 

Estimates ............................................................................................................... 17

6.2 Composite Wood Product Manufacturing ............................................................ 19

6.2.1 Potential Exposure Activities .................................................................... 19
Page x 

TABLE OF CONTENTS (Continued) 

Page 

x

6.2.2 Number of Establishments, Workers, Production Hours, and Work Day 

Estimates ............................................................................................................... 19

6.3 Downstream Product Manufacturing .................................................................... 22

6.3.1 Potential Exposure Activities .................................................................... 22

6.3.2 Number of Establishments, Workers, Production Hours, and Work Day 

Estimates ............................................................................................................... 23

6.4 Commercial Use.................................................................................................... 25

6.5 Consumer Use.....................................................................................25 

7.0 EXPOSURE ASSESSMENT BY CHEMICAL .......................................................................... 26

7.1 Formaldehyde Exposure during UF Resin Manufacturing ................................... 26

7.1.1 Process Description ................................................................................... 26

7.1.2 Exposure Assessment for Formaldehyde in UF Resin Manufacturing ..... 28

7.1.3 Uncertainty in Exposure Assessment ........................................................ 29

7.1.4 Environmental Releases of Formaldehyde during UF Resin Manufacturing

 .......................................................................................29

7.2 Methanol ............................................................................................................... 31

7.2.1 Manufacture of UF Resin.......................................................................... 31

7.2.2 Methanol in CWP Manufacture ................................................................ 35

7.2.3 Downstream Product Manufacture and Commercial/ Consumer Use ...... 38

7.3 Melamine .............................................................................................................. 39

7.3.1 Manufacture of MUF and Other Melamine-Based Resins ....................... 39

7.3.2 Melamine in CWP Manufacturing ............................................................ 40

7.3.3 Melamine Resins in Downstream Product Manufacturing and 

Commercial/ Consumer Use ................................................................................. 41

7.4 Epichlorohydrin .................................................................................................... 42

7.4.1 Manufacture of Polyamine Epichlorohydrin Resin .................................. 42

7.4.2 Manufacture of PureBond, HWPW, Downstream Product Manufacture, 

and Commercial/ Consumer Use .......................................................................... 47

7.5 Polymethylene Diphenyl Diisocyanate (pMDI) ................................................... 48

7.5.1 pMDI Resin Manufacture ......................................................................... 49

7.5.2 PB and MDF Manufacture ........................................................................ 52

7.5.3 Downstream Product Manufacture and Commercial/ Consumer Use. ..... 55

7.6 Vinyl Acetate Monomer (VAM) and Polyvinyl Acetate (PVA) .......................... 57

7.6.1 Manufacture of PVA resin ........................................................................ 57

7.6.2 HWPW Manufacturing ............................................................................. 63

7.6.3 Downstream Product Manufacture and Commercial/ Consumer Use ...... 63

7.7 Chromium (III) ...................................................................................................... 65

7.8 Ammonia............................................................................................................... 69

7.8.1 Ammonia in CWP Manufacture ............................................................... 69

7.8.2 Downstream Product Manufacture and Commercial/ Consumer Use ...... 71

7.9 Phenol ................................................................................................................... 73

7.9.1 Manufacture of Phenol-Formaldehyde Resin ........................................... 73

7.9.2 Phenolic Resins in CWP Manufacturing .................................................. 78

7.9.3 Downstream Product Manufacturing and Commercial/ Consumer Use ... 82
Page xi 

TABLE OF CONTENTS (Continued) 

Page 

xi

8.0 KEY UNCERTAINTIES AND LIMITATIONS OF WORKER EXPOSURE ESTIMATES ............ 83

9.0 REFERENCES ..................................................................................................................... 85
xii

LIST OF FIGURES

Page 

Figure 7-1. Process flow diagram for UF resin manufacturing (Kirk-Othmer, 2002a) ................ 27

Figure 7-2. Typical Phenolic Resin Production Unit (Kirk-Othmer, 2003a) ............................... 74
LIST OF TABLES

Page 

Table 2-1. Assessed Chemicals, Functions, and Applicable Life Cycle Stages ............................. 2

Table 2-2. NAICS Industry Sectors for Each Life Cycle Stage in the Exposure Assessment ....... 5

Table 3-1. Standard EPA Default Values for Use in the Worker Dermal Exposure Models ....... 11

Table 3-2. EPA Default Qualitative Assessments for Screening-Level Estimates of Dermal 

Exposure ............................................................................................................... 12

Table 6-1. Index Entries within NAICS Code 325211 (Plastics Material and Resin 

Manufacturing) Matched with Corresponding Resin Manufacturing Life Cycle 

Stages .................................................................................................................... 17

Table 6-2. Summary of 2002 Economic Census Data and Parameters Calculated from these Data 

for Resin Manufacturing Sites .............................................................................. 18

Table 6-3. Number of U.S. Hardwood Plywood Mills ................................................................. 21

Table 6-4. Number of U.S. Reconstituted Wood Product Mills ................................................... 21

Table 6-5. Summary of 2002 Economic Census Data and Parameters Calculated from these Data 

for CWP Manufacturing Sites ............................................................................... 21

Table 6-6. Summary of 2002 Economic Census Data and Parameters Calculated from this Data 

for Potential Downstream Product Manufacturing Sites ...................................... 24

Table 7-1. Occupational Exposure Limits for Formaldehyde ...................................................... 26

Table 7-2. Surrogate Inhalation Monitoring Data from OSHA IMIS Database used to represent 

Formaldehyde Concentrations during UF Resin Manufacturing .......................... 28

Table 7-3. Estimated Average Daily Concentrations for Data Representing Formaldehyde during 

UF Resin Manufacturing....................................................................................... 28

Table 7-4. Environmental Releases of Formaldehyde during Plastics Material and Resin 

Manufacturing as Reported in TRI for Reporting Year 2008 ............................... 30

Table 7-5. Occupational Exposure Limits for Methanol (CASRN 67-56-1) ................................ 31

Table 7-6. Surrogate Inhalation Monitoring Data from OECD used to represent Methanol 

Concentrations during UF Resin Manufacturing .................................................. 32

Table 7-7. Estimated Average Daily Concentrations for Data Representing Methanol during UF 

Resin Manufacturing ............................................................................................. 32

Table 7-8. Environmental Releases of Methanol during Plastics Material and Resin 

Manufacturing Reported in TRI for Reporting Year 2008 ................................... 34
LIST OF TABLES (Continued) 

Page 

xiv

Table 7-9. Estimated “What-If” Average Daily Concentrations of Methanol During CWP 

Manufacturing, based on the OSHA PEL ............................................................. 35

Table 7-10. Environmental Releases of Methanol during CWP Manufacturing Reported in TRI 

for Reporting Year 2008 ....................................................................................... 37

Table 7-11. Estimated Average Daily Concentrations of Surrogate Inhalation Monitoring Data 

from OECD used to represent Melamine Concentrations during Melamine-Based 

Resin Manufacturing ............................................................................................. 40

Table 7-12. Occupational Exposure Limits for Epichlorohydrin ................................................. 42

Table 7-13. PPE Considerations during Use of Epichlorohydrin ................................................. 43

Table 7-14. Inhalation Monitoring Data from OSHA IMIS Database for Epichlorohydrin during 

PAE Production .................................................................................................... 44

Table 7-15. Estimated Average Daily Concentrations of Epichlorohydrin during Manufacture of 

PAE Resin ............................................................................................................. 44

Table 7-16. Environmental Releases of Epichlorohydrin during Plastics Material and Resin 

Manufacturing (NAICS Code 325211) and All Other Miscellaneous Chemical 

Product and Preparation Manufacturing (NAICS Code 325998) Reported in TRI 

for Reporting Year 2008 ....................................................................................... 46

Table 7-17. Occupational Exposure Limits for MDI and pMDI .................................................. 48

Table 7-18. Inhalation Monitoring Data from EU Risk Assessment for MDI/ pMDI 

Concentrations during pMDI Resin Manufacturing ............................................. 49

Table 7-19. Estimated Average Daily Concentrations for Data Representing MDI/ pMDI during 

pMDI Manufacturing ............................................................................................ 50

Table 7-20. Releases of MDI During Plastics Material and Resin Manufacturing Reported in TRI 

for Reporting Year 2008a

 ...................................................................................... 51

Table 7-21. Inhalation Monitoring Data from EU Risk Assessment for MDI/ pMDI 

Concentrations during PB Manufacturing ............................................................ 52

Table 7-22. Estimated Average Daily Concentrations for Data Representing MDI/ pMDI during 

PB and MDF Manufacturing ................................................................................ 52

Table 7-23. Releases of MDI during Reconstituted Wood Product Manufacturing Reported in 

TRI for Reporting Year 2008a

 .............................................................................. 54

Table 7-24. Releases of MDI in Various Downstream Product Manufacturing Industries 

Reported in TRI for Reporting Year 2008a

 ........................................................... 56

Table 7-25. Occupational Exposure Limits for Vinyl Acetate Monomer (CASRN 108-05-4) .... 57
LIST OF TABLES (Continued) 

Page 

xv

Table 7-26. VAM Permeation Times for Various PPE Materialsa

 ............................................... 59

Table 7-27. Surrogate Inhalation Monitoring Data from Data Representing VAM Concentrations 

during PVA Resin Manufacturing a ...................................................................... 60

Table 7-28. Estimated Average Daily Concentrations for Data Representing VAM during PVA 

Production using Surrogate Data from the EU Risk Assessment ......................... 61

Table 7-29. Releases of VAM during Plastics Material and Resin Manufacturing Reported in 

TRI for Reporting Year 2008 ................................................................................ 62

Table 7-30. Occupational Exposure Limits for Chromium (III) (CASRN 16065-83-1) .............. 65

Table 7-31. Release of Chromium and Chromium Compounds during Plastics Material and 

Resin Manufacturing Reported in TRI for Reporting Year 2008 ......................... 67

Table 7-32. Releases of Chromium and Chromium Compounds during Downstream Product 

Manufacturing Reported in TRI for Reporting Year 2008 ................................... 68

Table 7-33. Exposure Limits for Ammonia (CASRN 7664-41-7) .............................................. 69

Table 7-34. Estimated “What-If” Average Daily Concentrations of Ammonia Based on the 

OSHA PEL............................................................................................................ 70

Table 7-35. Environmental Releases of Ammonia during Hardwood Veneer and Plywood 

Manufacturing (NAICS Code 321211) and Reconstituted Wood Product 

Manufacturing (NAICS Code 321219) Reported in TRI for Reporting Year 2008a

............................................................................................................................... 72

Table 7-36. Occupational Exposure Limits for Phenol (CASRN 108-95-2) ................................ 73

Table 7-37. Inhalation Monitoring Data from 2006 EU Risk Assessment for Phenol during 

Phenolic Resin Manufacturing .............................................................................. 75

Table 7-38. Estimated Average Daily Concentrations for Data Representing Phenol during 

Phenolic Resin Manufacturing .............................................................................. 75

Table 7-39. Environmental Releases of Phenol during Plastics Material and Resin 

Manufacturing Reported in TRI for Reporting Year 2008 ................................... 77

Table 7-40. Inhalation Monitoring Data from 2006 EU Risk Assessment for Phenol during 

Phenolic Resin Processing .................................................................................... 78

Table 7-41. Estimated Average Daily Concentrations for Data Representing Phenol during CWP 

Manufacturing ....................................................................................................... 79

Table 7-42. Environmental Releases of Phenol during Reconstituted Wood Product 

Manufacturing Reported in TRI for Reporting Year 2008 ................................... 81
Formaldehyde Substitutes Exposure and Release Assessment – Draft Final 

October, 2011 – draft deliberative – do not cite or quote 

Page 1 

1.0 INTRODUCTION AND PURPOSE

In a rulemaking under the Toxic Substances Control Act (TSCA) Title VI, the 

Environmental Protection Agency (EPA) is regulating formaldehyde emissions from composite 

wood products (CWPs), which include hardwood plywood (HWPW), medium-density 

fiberboard (MDF), and particleboard (PB). As part of this rulemaking, EPA is reviewing 

substitute technologies to reduce formaldehyde emissions from CWPs. This report presents 

information about the potential for occupational exposures to and environmental releases of 

formaldehyde in urea-formaldehyde (UF) resins and some chemicals involved in the substitute 

technologies. This report will refer to these chemicals as “substitute chemicals” or “substitutes”. 

The report presents worker exposure estimates for the set of chemicals and workplaces discussed 

in the Scope section below. Available release data related to the scope are presented for 

informational purposes only. Appendix A includes definitions of key technical terms used in this 

section and throughout the remainder of this report. 

2.0 SCOPE OF THE ASSESSMENT

The scope of this assessment includes substitute chemicals with toxic effects ranging 

from medium to high depending on the endpoint (USEPA, 2011a). Substitutes include monomers 

of resins that are alternatives to urea-formaldehyde (UF) resins, additives to UF and alternate 

resins, and treatment chemicals. The life cycle stages included within the scope of this report 

vary for each substitute chemical and depend on the function of the substitute chemical in the 

specific type of composite wood product for which it is used. The life cycle stage for a specific 

substitute chemical begins at resin manufacture or at the next earliest stage in the CWP life cycle 

into which the substitute chemical is introduced. The possible life cycle stages are resin 

manufacturing, CWP manufacturing, downstream product manufacturing and commercial/ 

consumer use. In this case, exposures during consumer use include not only exposures that 

would occur to home hobbyists, but secondary exposure to the consumers who purchase and use 

articles, such as book shelves, entertainment centers, etc. composed of CWPs made with 

substitute chemicals. All of these steps except resin manufacturing are described in detail in 

“Assessment of Occupational Exposure to Formaldehyde from Composite Wood Products” 

(USEPA, 2011b), and their processes will only be summarized in this report. Table 2-1 lists the 

substitute chemicals, their functions, and the applicable life cycle stages for each included in this 

report. 

Additionally, occupational exposures to and environmental releases of formaldehyde 

from UF resin manufacture were not included in the scope of “Assessment of Occupational 

Exposure to Formaldehyde from Composite Wood Products” (USEPA, 2011b). However, 

because resin manufacture was included in the scope of substitutes’ analyses, occupational 

exposures to and environmental releases of formaldehyde in UF resin manufacture are included 

in this report to provide balance of coverage between formaldehyde and the substitutes. 
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Table 2-1. Assessed Chemicals, Functions, and Applicable Life Cycle Stages 

Assessed Chemicals Function of Chemical Applicable Life Cycle Stages 

Formaldehyde 

CASRN: 50-00-0 

- Monomer for urea-formaldehyde 

(UF) resin - UF resin manufacturing 

Methanol 

CASRN: 67-56-1 

- Additive to urea-formaldehyde (UF) 

resin 

- UF resin manufacturing CWP 

manufacturing 

- Downstream product manufacturing 

- Commercial/ Consumer use 

Melamine 

CASRN: 108-78-1 

- Monomer for melamine-ureaformaldehyde (MUF) resin 

- Additive to other resins used in CWP 

manufacturing 

- MUF and other resin manufacturing 

- CWP manufacturing 

- Downstream product manufacturing 

- Commercial/ Consumer use 

Epichlorohydrin 

CASRN: 106-89-8 - Component in PureBond resin 

- Polyamine epichlorohydrin resin 

manufacturing 

- PureBond manufacturing 

- CWP manufacturing 

- Downstream product manufacturing 

- Commercial/ Consumer use 

Polymethylene Diphenyl 

Diisocyanate (pMDI) 

CASRN: 9016-87-9 

- Resin (polymethylene diisocyanate 

(pMDI) resin) 

- pMDI resin manufacturing 

- CWP manufacturing 

- Downstream product manufacturing 

- Commercial/ Consumer use 

Vinyl Acetate Monomer 

(VAM) 

CASRN: 108-05-4 

- Monomer in polyvinyl acetate (PVA) 

resin 

- PVA resin manufacturing 

- CWP manufacturing 

- Downstream product manufacturing 

- Commercial/ Consumer use 

Chromium (III) 

CASRN: 16065-83-1 

- Additive in polyvinyl acetate (PVA) 

resin 

- Addition of Cr(III) salts to PVA resin 

- CWP manufacturing 

- Downstream product manufacturing 

- Commercial/ Consumer use 

Ammonia 

CASRN: 7664-41-7 

- Additive (reacted into resin molecule) 

- Additive (added in CWP process); 

- Post-pressing treatment agent. 

- CWP manufacturing 

- Downstream product manufacturing 

- Commercial/ Consumer use 

Phenol 

CASRN: 108-95-2 

- Monomer for phenol-formaldehyde 

(PF) resin 

- PF resin manufacturing 

- CWP manufacturing 

- Downstream product manufacturing 

- Commercial/ Consumer use 

2.1 Life Cycle Stages

Subsections 2.1.1 through 2.1.4 briefly describe the life cycle stages within the scope of 

this report. 
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2.1.1 Resin Manufacturing 

Resin manufacturing refers to the use of the substitute to produce resins that may be used 

in the manufacture of HWPW, MDF, and PB. The life cycles for chemicals that are resin 

monomers begin during their use in the appropriate resin manufacturing step. 

2.1.2 Composite Wood Product (CWP) Manufacturing (Primary Manufacturing) 

The terms “composite wood product manufacturing” and “primary manufacturing” in this 

report refer specifically to the manufacture of HWPW, MDF, and PB. 

NAICS code 321219 - Reconstituted Wood Product Manufacturing includes both the 

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

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

waferboard (U.S Census Bureau, 2002a). 

NAICS code 321211 - Hardwood Veneer and Plywood Manufacturing includes the 

manufacture of hardwood plywood. It also includes the manufacture of hardwood veneers, which 

are not included in the scope of this assessment (U.S Census Bureau, 2002a).

2.1.3 Downstream Product Manufacturing 

After CWP manufacturing, HWPW, MDF, and PB may be converted into articles or 

other downstream 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, 2000a). 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. PB is used as floor decking in manufactured homes, underlayment in 

conventional homes, shelving, door cores, stair stepping, door frames, and a host of other uses 

that require small flat parts as a starting point. On the other hand, MDF is not used as floor 

underlayment or decking except on special request. A small portion of PB is also extruded or 

molded into furniture parts, brush bases and toilet seats (Kirk-Othmer, 2000a).

2.1.4 Commercial/ Consumer Use 

The commercial/ consumer use of CWPs includes (1) the use of CWPs in on-site 

construction and (2) the utilization by office workers of work-place buildings (commercial 

buildings) containing CWPs and downstream products constructed of CWPs (such as furniture 

and cabinets). Home hobbyists who construct their own furniture may be exposed to the same 

type of CWP boards as commercial furniture builders. Also, new furniture is generally 

purchased by consumers in boxes and assembled in homes. Such boxed furniture may be 

constructed of CWP boards made using the same substitute chemicals that are the subject of this 

report. Furniture that contains CWPs include: entertainment centers, book shelves, baby cribs, 

baby changing tables, etc. Secondary exposure to home occupants may occur (as in the case 
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with formaldehyde), if the chemicals are volatile. In the chemistry evaluation of substitute 

chemicals conducted by EPA for this effort, all volatile chemicals are expected to be released 

earlier during the manufacturing/processing stage of the life cycle, therefore, exposures are 

generally expected to be negligible. (USEPA. 2011c) 

2.2 NAICS Codes Associated with Life Cycle Stages

For formaldehyde and each of the substitutes, each of the life cycle stages discussed 

above was matched with appropriate North American Industry Classification System (NAICS) 

codes. NAICS codes are used to identify particular industries and are essential in retrieving data 

from the OSHA Integrated Management Information System (IMIS), Toxic Release Inventory 

(TRI), and the U.S. Economic Census which are discussed in Sections 3.0, 4.0, and 6.0 below. 

Table 2-2 lists the NAICS codes used for each life cycle stage, which are discussed further in 

Section 6.0. 
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Table 2-2. NAICS Industry Sectors for Each Life Cycle Stage in the Exposure Assessment 

NAICS 

Corresponding 

1987 SICa Description 

Resin Manufacturing 

325199 2869, 2899 All Other Basic Organic Chemical Manufacturing 

325211 2821 Plastics Material and Resin Manufacturing 

325998 

2819, 2899, 

3952, 3999, 

7389 

All Other Miscellaneous Chemical Product and Preparation Manufacturing 

Primary Manufacturing (Composite Wood Products) 

321219 2493 Reconstituted wood product manufacturing 

321211 2435 Hardwood veneer and plywood manufacturing 

Downstream Product Manufacturing 

321911 2431 Wood window and door manufacturing 

321918 2431 Other millwork (including flooring) 

321991 2451 Manufactured home (mobile home) manufacturing 

321992 2452 Prefabricated wood building manufacturing 

337110 2434 Wood kitchen cabinet and counter top manufacturing 

337121 2512 Upholstered household furniture manufacturing 

337122 2511 Nonupholstered wood household furniture manufacturing 

337127 2541 Institutional furniture manufacturing 

337129 2517 Wood television, radio, and sewing machine cabinet manufacturing 

337211 2521 Wood office furniture manufacturing 

337212 2541 Custom architectural woodwork and millwork manufacturing 

337215 2541 Showcase, partition, shelving, and locker manufacturing 

Commercial/ Consumer Use

N/A N/A N/A 

N/A – Not applicable – there are no NAICS codes applicable to the use of CWP products during building 

construction or for workers using commercial buildings. Likewise, there are no NAICS codes associated with 

consumer or home hobbyist use. 

a – Standard Industrial Classification (SIC) codes were replaced by the NAICS system in 1997. SIC codes were also 

searched in the OSHA IMIS database. 

 
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3.0 OCCUPATIONAL AND CONSUMER EXPOSURE ASSESSMENT METHODS

The data collection efforts, the methods utilized for estimating occupational and 

consumer exposures and the use of these methods are discussed in this section. 

3.1 Occupational Data Collection

It was outside the scope of the assessment to obtain primary data through direct sampling 

methods. Therefore, this exposure assessment relied on the use of a limited number of sources of 

readily available secondary data, such as prior research studies and reports, to characterize 

occupational exposures from substitute chemicals during their life cycle in the CWP industry. A 

comprehensive review of readily available government, industry and academic sources was 

conducted, including: EPA, OSHA, NIOSH, Organization for Economic Co-operation and 

Development (OECD), industry websites, academic journals, and publications. The information 

and data were compiled according to the data preference criteria, which are presented in 

Appendix B of this report. The following subsections discuss the major sources of data used in 

this assessment. 

3.1.1 OSHA IMIS Data 

 Inhalation monitoring data were primarily obtained from OSHA’s IMIS database. IMIS is 

an online data entry and information retrieval system designed to collect, process, retrieve, and 

communicate penalty assessment, arbitration, and collection information regarding OSHA 

inspections. The monitoring data in this database were collected during OSHA inspections that 

were conducted between January 1979 and April 2010 in the US (OSHA, 2010). For each data 

point, the database contained information on the 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 level, exposure concentration measurement type 

(personal or area measurement), exposure type (i.e., time weighted average (TWA), ceiling, 

short-term, etc.), frequency or duration of exposure, number of employees at the inspected 

facility, and the number of employees exposed. IMIS was searched by NAICS code query. 

OSHA IMIS data were obtained through requests to OSHA made on April 23, 2010 and 

September 23, 2010. 

The main types of monitoring data available in the OSHA IMIS database are TWA, 

ceiling, short-term or not found (NF).1

 Only TWA data were used in this assessment because 

only TWA data can be used to calculate average daily concentrations. 

Short-term or ceiling values present the highest concentration at the time of the 

measurement, but do not specify the duration of exposure. This level of exposure may be much 

lower when averaged over an 8-hour period. Measurements that resulted in a non-detected (NF) 

formaldehyde concentration did not include their measurement type in the OSHA IMIS database 

 

1

 Not found (NF) indicates that the chemical was not detected during monitoring. 
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(i.e., TWA or STEL measurement type). Therefore, it is unknown whether a non-detected value 

was measured over an eight hour duration or a fifteen minute duration. For this reason, nondetected and not-found results were also excluded. 

3.1.2 International Reports and Assessments 

The other main sources of monitoring data were OECD SIDS reports and EU Risk 

Assessments. These sources typically summarized the monitoring data as a range of values and 

often did not indicate the sampling method or limits of detection. Additionally, mean and median 

values were typically not reported. Canadian reports and assessments were also researched, but 

no data directly relevant to this assessment were found. 

3.2 Approach for Assessing Occupational Exposures

This report was developed in advance of a hazard report for the substitutes, so inhalation 

and dermal exposures were assessed regardless of potential toxic effects (e.g., cancer or noncancer). The following subsections describe the methods for assessing inhalation and dermal 

occupational exposures. 

3.2.1 Inhalation Exposures 

Due to data limitations, this exposure assessment characterizes overall chemical 

exposures at a site; therefore, the data presented in this assessment represent total chemical 

exposures at sites in each specific life cycle stage. For each substitute chemical and relevant life 

cycle stage, inhalation exposures were assessed by determining the Average Daily Concentration 

(ADC) and Lifetime Average Daily Concentration (LADC), using Equation 3-1 (USEPA, 

2009b): 

AT

CA ET EF ED EC (    )  (3-1)

Where: 

 EC = Exposure concentration (μg/m3

) 

CA = Contaminant concentration in air (μg/m3

) 

ET = Exposure time (hr/day; default: 8 - see Sections 6.1.2, 6.2.2, and 

6.3.2) 

EF = Exposure frequency (days/yr; default: 250 - see Sections 6.1.2, 

6.2.2, and 6.3.2) 

ED = Exposure duration (years; ADC and LADC: 40 years) 

AT = Averaging time (lifetime in years x 365 days/yr x 24 hours/day; 

ADC: 40 years, LADC: 70 years) 

 In the instances where monitoring data were not available but exposure were considered 

possible, inhalation exposure assessments were made using the OSHA PEL values, which are 

characterized as ”what-if” type estimates (USEPA, 1997a). The use of OSHA PELs as "what-if" 
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assume that the workplaces using the substitute chemical are at least in OSHA compliance with 

regard to the PEL for the substitute chemical. Where chemicals were monomers that had been 

reacted or additives that would not likely to be released from a resin matrix, inhalation exposures 

are characterized as negligible. Negligible inhalation exposures are defined as < 0.01 mg/m3

TWA. 

3.2.2 Dermal Exposures 

Dermal exposure data and estimates were typically not available from most of the 

literature sources used for this report. Some EU Risk Assessments estimated dermal exposures 

using the European Estimation and Assessment of Substance Exposure (EASE) model. These 

EASE model estimates are presented in this report only to allow comparison to EPA model 

estimates (see Section 3.2.2). 

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. 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 3-2 (USEPA, 1991a; USEPA, 2000). 

Equation 3-2 uses unique default values based upon the nature of the contact and the physical 

form of the chemical material. These default values are summarized in Table 3-1. 
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 EXPdermal  AREA surface  Qremain_ski n  Fchem  Nevent (3-2) 

Where: 

EXPdermal = Dermal exposure to the liquid or solid chemical per day (mg 

chemical/worker-day) 

AREAsurface = Surface area of the skin that is in contact with liquid or solid material 

containing the chemical (cm2

; see Table 3-1 for appropriate EPA 

default values) 

Qremain_skin = Quantity of the liquid or solid material containing the chemical that 

remains on the skin after contact (mg/cm2

-event; see Table 3-1 for 

appropriate EPA default values) 

Fchem = Weight fraction of the chemical of interest in the material being 

handled in the activity (dimensionless; refer to the ESD discussion for 

guidance on appropriate default value) 

Nevent = Frequency of events for the activity (EPA default = 1 event/workerday2

) 

 Dermal dose in this report are estimated in units further normalized by worker body 

weight, as indicated in Equation 3-3: 

 

 dermal_bw dermal BW worker EXP  EXP / (3-3) 

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) 

BWworker = Body weight of an average worker (kg; EPA default value = 70 kg 

(USEPA, 1997b)) 

For several categories of exposure, EPA uses qualitative assessments to estimate dermal 

exposure. Table 3-2 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. 

Dermal exposures to vapors and gases such as ammonia are not quantifiable and are not included 

in this report. 

 

2

Only one contact per day (Nevent = 1 event/worker-day) is assumed because Qremain_skin, with few exceptions, is not 

expected to be significantly affected either by wiping excess chemical material from skin or by repeated contacts 

with additional chemical material (i.e., wiping excess from the skin does not remove a significant fraction of the 

small layer of chemical material adhering to the skin and additional contacts with the chemical material do not add a 

significant fraction to the layer). Exceptions to this assumption may be considered for chemicals with high volatility 

and/or with very high rates of absorption into the skin. 
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Several of the other substitute chemicals also have volatility that, if the chemical is 

handled in nearly pure forms or in highly concentrated and volatile mixtures, cause exception to 

the default assumption Nevent = 1, noted for Equation 3-2 (see associated footnote). These 

chemicals include formaldehyde, methanol, epichlorohydrin, and vinyl acetate, with vapor 

pressures of 51, 96, 13, and 83 mmHg, respectively (NIOSH, 2005). Because there is not 

enough information to determine alternative values to the default for Nevent, dermal exposures to 

these chemicals are not estimated in this report when the chemical is expected to be handled in 

nearly pure forms or in highly concentrated and volatile mixtures.
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Table 3-1. Standard EPA Default Values for Use in the Worker Dermal Exposure Mode

Default Model Example Activities 

AREAsurfacea

(cm2) 

Qremain_skinb

(mg/cm2-

event) 

A

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 

EPA/OPPT 2-Hand Dermal Contact with Liquid Model

Maintenance Manual cleaning of equipment and containersFilling drum with liquidConnecting transfer line

840 

(2 hand mean) 

Low: 0.7 

High: 2.1 

EPA/OPPT 2-Hand Dermal Immersion in Liquid Model

Handling wet surfaces Spray painting

840 

(2 hand mean) 

Low: 1.3 

High: 10.3 

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 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 equipmentHandling wet or dried material in a filtration and 

drying process

No defaults No defaults 

a - These default values were adopted in the 2000 EPA report on screening-level dermal exposure estimates (USEPA, 2000) and are the 

taken from the EPA Exposure Factors Handbook, 1997 (USEPA, 1997b). b - These default values were adopted in the 2000 EPA report on screening-level dermal exposure estimates (USEPA, 2000). The repor

ranges of values for liquid handling activities from: U.S. EPA. A Laboratory Method to Determine the Retention of Liquids on the Surf

Environmental Protection Agency, Office of Pollution Prevention and Toxics, Exposure Evaluation Division. EPA 747-R-92-003. Septc - These default values were adopted in the 2000 EPA report on screening-level dermal exposure estimates (USEPA, 2000). The repor

dermal contact for solids handling activities from: Lansink, C.J.M., M.S.C. Breelen, J. Marquart, and J.J. van Hemmen: Skin Exposure the Paint Industry. Preliminary Modeling of Skin Exposure Levels to Powders Based on Field Data (TNO Report V 96.064). Rijswijk, 

Nutrition and Food Research Institute, 1996.
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Table 3-2. 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). 

3.3 Qualitative Consumer Exposure Method 

Consumers include home hobbyists, the purchaser of an article, the user of the article, 

and in a broader sense, the people who occupy the same space as the article. In this case the 

articles, for example, entertainment centers or book cases, are made of the CPWs that contain the 

substitute chemicals of interest in this report. Consumer and commercial use will be similar in 

nature but the commercial user will have a much higher exposure frequency to new products. In 

general new products are considered to provide the highest exposure levels of volatile chemical 

as volatile chemicals emission over time have been shown to decline exponentially. In the 

commercial setting, workers will continually work with new boards, while most consumers will 

install a limited number of new products over a greater amount of time. Therefore, only 

qualitative estimates are provided for consumers and are generally based on the conclusion 

drawn about commercial users. 

4.0 RELEASE DATA COLLECTION AND PRESENTATION 

A preliminary data search for releases of substitute chemicals was begun for this report 

using one main source. EPA then determined that releases would not be used for other EPA 

analyses, so no further data searches or analyses were conducted. This report presents the 

preliminary data search approach and data found for informational purposes only. This section 

describes the preliminary data search approach. 

Release estimates were determined by using EPA’s Toxic Release Inventory (TRI) 

database. TRI is a program created under the Emergency Planning and Community Right-toKnow Act (EPCRA) that collects information on multi-media (e.g., land, water, air, etc.) releases 

and waste management activities for toxic chemicals in the U.S. Pursuant to Section 313 of 

EPCRA, TRI data are gathered on a reporting-year basis and can be divided by industry sectors 

(NAICS codes). The data for this analysis were collected from reporting year 2008. 

EPA requires all federal facilities and TRI-regulated facilities, based on the 

“manufacturing sector” (based on SIC codes 20 through 39) to report releases to TRI. Facilities 
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are required to report to TRI if the facility manufactures (which includes imports), processes, or 

otherwise uses any EPCRA Section 313 chemical in quantities greater than the established 

threshold (typically 25,000 pounds, but far less for persistent, bioaccumulative and toxic 

chemicals) in the course of a reporting year and has greater than a certain number of employees 

(10). There are several caveats associated with TRI release data: 

 There can be chemical manufacturers and processors that are not subject to TRI based on 

many criteria, and therefore TRI will underestimate overall releases. 

 TRI does not have a specific line item for “quantity sent to incineration”. However, there 

are TRI data elements that require facilities to identify quantities sent to on-site and to 

off-site treatment and to identify the “type” of treatment via a TRI-specific code. There 

are many “types” that correspond to thermal destruction (e.g., codes for incinerators, 

flares, thermal oxidizers, energy recovery, etc.). Releases to incineration were determined 

based on the appropriate codes. 

 TRI requires estimates for all release and waste management quantities, including those 

associated with “remedial actions, catastrophic and one-time events”. Therefore, some 

TRI releases are atypical and are not expected on a recurring basis. 

 There is no method of determining the production volume or use volume associated with 

the facility. Submission of a TRI report is recognition that at least one threshold was 

exceeded; however, the facility does not provide the quantity associated with any activity. 

 Facilities must identify whether they manufacture, process, and/or otherwise use the 

chemical. However, if they identify multiple activities it is not possible to distinguish the 

quantity associated with each. For example, if a facility manufactures and processes the 

chemical, the reported release amounts are a combination of all releases from the 

manufacturing and also the processing steps. 

 Use of TRI data, much like OSHA PELs, assumes a generally compliant and welloperated facility, and therefore does not take into account atypical scenarios, or those 

under, for example, EPA Enforcement. 

5.0 LIMITATIONS OF ASSESSMENT METHOD AND UNCERTAINTY ASSOCIATED WITH 

RESULTS

This section discusses the limitations of the assessment methods presented above and the 

general uncertainty associated with the results. 

5.1.1 Amount of Exposure Data Available 

A constraint in this assessment is the amount of exposure monitoring data available in the 

literature. In almost all data sets, there are not enough data to establish a distribution of exposure 

concentrations or to determine a basis for outliers. Additionally, the type of inhalation 
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concentrations (average, 95th percentile, single point value, assumed high-end) were not 

consistent for the each chemical. This uncertainty and variability, as related to worker inhalation 

exposures in this report, indicate that direct quantitative comparison between various chemicals 

and life cycle stages is likely to be imprecise. 

5.1.2 Applicability of Exposure or Release Data 

OSHA IMIS monitoring data and TRI release data were obtained using the NAICS codes 

associated with the life cycle stage of interest. However, it is impossible to further refine the data 

to the level required for this assessment. For example, there are many types of resin 

manufacturing facilities that can be classified under the Plastics Material and Resin 

Manufacturing NAICS code, but there is no way to identify the specific type of facility within 

the NAICS code. Therefore, all OSHA IMIS and TRI data are considered to be surrogate data 

unless otherwise specified. 

5.1.3 Representativeness of Monitoring Data and Models 

OSHA IMIS data are only collected at a facility in response to a complaint, referral, or as 

part of a voluntary/elective program. Therefore, monitoring data is obtained from a limited 

number of sites, and the facilities that were selected to obtain this information may not be 

representative of the overall industry, as they are either a part of a complaint/referral (e.g., 

alleged non-compliance) or a voluntary/elective program (e.g., “beyond compliance”). 

OECD SIDS and EU Risk Assessment data are typically collected from other countries. 

Worker conditions may be drastically different than those in the U.S. and may not properly 

represent U.S. occupational exposures and environmental releases. 

Much of the exposure data used in this assessment were not measured in the past five 

years. Facility conditions may have changed with the addition of new chemical technologies, 

process technologies, engineering controls, or PPE. 

Modeling inhalation exposures due to lack of data sometimes employs the assumption of 

compliance with the OSHA PEL and therefore a concentration at or below the PEL. EPA 

conducted an informal review of a limited set of monitoring data for some substances with 

OSHA PELs, and the review indicated that use of such modeling tends to generally overestimate 

exposure concentrations, and sometimes very significantly (e.g., orders of magnitude). 

Modeling dermal exposures has a number of limitations and uncertainties. For example, 

the EPA models are intended for use in screening-level assessments and provide an estimate of 

potential dermal exposure and do not take into account the protection from the possible use of 

gloves. Hand exposure only is assumed because available data indicates that hand exposure 

constitutes the majority of the total body exposure. (USEPA, 2000) 

5.1.4 Sources of Exposure 

In many cases, monitoring data are collected and presented for a general area or for 

particular worker activities. However, these monitoring data do not indicate the specific source 
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of exposure. For example, monitoring data do not distinguish whether the source of measured 

chemical exposure is from the resin, the wood or adjacent processes unrelated to CWPs. 

Therefore, it is not possible to determine what portion of the measured concentration can be 

attributed to the CWPs. 

5.1.5 Frequency and Duration of Exposure 

The OSHA IMIS database includes some data on the frequency and duration of worker 

exposure, but many sites did not provide data. For the data available, there is variability in the 

various worker activities and sites. These worker activities typically cannot be matched between 

sites; therefore the frequency and duration of worker exposures also cannot be compared 

directly. Monitoring data found in EU Risk Assessments and OECD SIDS reports typically did 

not report the average duration and frequency of exposures. 

For the purpose of calculating exposures, the duration and frequency of exposure was 

assumed to be 8 hours per day and 250 days per year where better assumptions for duration of 

exposure were not available. Economic census data are presented in Section 6.0 that support the 

use of this assumption. 

5.1.6 Number of Sites and Workers 

Specific information on the number of CWP manufacturing sites was provided from trade 

associations. However, these estimates under-represent the number of sites and workers in 

existence, because trade associations represent only a segment of industry, and may exclude 

smaller facilities. 

Although there is some current information on the number of CWP manufacturing sites 

from the trade associations, limited information is available to describe resin manufacturing, 

downstream product manufacturing, and commercial use industries. The U.S. Economic Census 

provides representative estimates of the numbers of chemical manufacturers, resin 

manufacturers, and downstream product manufacturers for each relevant industry and the 

respective number of production workers or employees in each industry. 

However, as stated previously, the Economic Census reports information according to 

NAICS codes, which may encompass facilities that may not be involved in the manufacture, 

distribution, or use of the composite wood products of interest. Additionally, each site within the 

industries may or may not use the particular chemical of interest. Furthermore, the census data 

were taken in 2002, which is prior to the data quality preference year of 2005. Therefore, these 

factors indicate that a limited level of detail and accuracy are possible for these parameters. 

5.1.7 Post-CARB Rule Exposures 

In 2007, the California Air Resources Board (CARB) adopted a regulation that 

established maximum formaldehyde emissions from the three types of CWPs. EPA was 

petitioned in March 2008 under TSCA Section 21 to adopt similar regulations. This petition 

spurred the development of several analyses, including this exposure assessment. 
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A significant limitation of the data and methods in this report is the lack of a method to 

further extrapolate the estimated inhalation exposure concentrations (LADCs and ADCs) from 

pre-CARB levels to several post-CARB exposure concentrations of interest. 

 EPA has a particular interest in two sets of exposure concentrations: pre-rule baseline and 

post-rule. Pre-rule baseline corresponds to expected exposures immediately prior to the rule’s 

implementation. Post-rule corresponds to expected exposures following the rule’s 

implementation. 

Exposure monitoring data gathered for this report were generated prior to CARB 

regulatory implementation. The effects of implementation of the CARB rule and of this federal 

rule on worker exposures cannot be simply determined because the data is not yet available. The 

effects of these rules on worker exposures to formaldehyde in UF resin manufacture could be to 

decrease one or a combination of the following parameters (as compared to pre-CARB 

formaldehyde regulation): expected exposure concentrations of formaldehyde, numbers of 

workers exposed, exposure frequency (days/yr), exposure duration (hours/day). The effects of 

these rules on worker exposures to the substitute chemicals (other than formaldehyde) in the 

various life cycle stages noted in this report could be to increase one or a combination of the 

following parameters (as compared to pre-CARB): expected exposure concentrations of the 

chemical, numbers of workers exposed, exposure frequency (days/yr), exposure duration 

(hours/day). 

The complexities of the CARB regulation and proposed federal rules’ effects on these 

sets of parameters could not be quantified for this report. 

6.0 GENERAL PROCESS DESCRIPTIONS AND FACILITY ESTIMATES

This section presents general facility estimates for resin manufacturing, primary 

manufacturing, and downstream manufacturing for the substitute chemicals and composite wood 

products. General facility estimates include NAICS industry sectors, census estimates on the 

number of establishments and production workers, and average production hours per worker. 

This section also compares census-derived exposure durations and exposure frequencies with 

assumptions used for exposure duration (eight hours per day) and exposure frequency (250 days 

per year). 

6.1 Resin Manufacturing

NAICS codes have index entries that list the specific types of industries that are 

applicable to the particular NAICS code.3

 The index entries were searched for the various types 

of resin manufacturing. Several types of resin manufacturing were classified under NAICS code 

 

3

 NAICS code search is available on the U.S. Census Bureau Web Site: http://www.census.gov/cgibin/sssd/naics/naicsrch?chart=2007
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325211 – Plastics Material and Resin Manufacturing. Table 6-1 presents the index entries that 

were matched with the life cycle stages assessed in this report. 

Table 6-1. Index Entries within NAICS Code 325211 (Plastics Material and Resin 

Manufacturing) Matched with Corresponding Resin Manufacturing Life Cycle Stages 

Index Entries within NAICS Code 325211 (Plastics 

Material and Resin Manufacturing) Corresponding Life Cycle Stage 

Urea-formaldehyde resins manufacturing UF Resin Manufacturing 

Vinyl acetate resins manufacturing PVA Resin Manufacturing 

Melamine resins manufacturing MF and MUF Resin Manufacturing 

Phenol-formaldehyde resins manufacturing PF Resin Manufacturing 

Diisocyanate resins manufacturing pMDI Resin Manufacturing 

It is unclear where polyamine epichlorohydrin (PAE) resin manufacturing may be 

classified, but based on TRI reporting by Hercules, Inc.4

, a known PAE manufacturer, PAE 

manufacturing may possibly fall under NAICS codes 325211 - Plastics Material and Resin 

Manufacturing, 325199 - All Other Basic Organic Chemical Manufacturing, or 325998 - All 

Other Miscellaneous Chemical Product and Preparation Manufacturing. 

6.1.1 General Resin Manufacturing Process 

In general, resins are made via batchwise processes. For example, UF resin is 

manufactured by charging formaldehyde and other reactants to a kettle. A variety of posttreatment processes may be applied, and the product is drummed for sale (Kirk-Othmer, 2002a). 

More detailed process descriptions are described in the respective sections for each chemical in 

Section 7.0, where applicable. 

6.1.2 Number of Establishments, Workers, Production Hours, and Work Day Estimates 

Estimates for the total number of workers and aggregate production hours for resin 

manufacturing were obtained from the 2002 Economic Census for the NAICS codes discussed 

above in Table 2-2 (U.S. Census Bureau, 2002a). Using these data, an 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. The results are given in Table 6-2. The 

calculated days per year and hours per day for each NAICS industry code associated with 

chemical and resin manufacturing deviate from the assumed values for frequency of exposure of 

250 days per year and duration of exposure of 8 hours per day by less than 10 percent (USEPA. 

1992b). Therefore, this assessment uses the assumed values for exposure duration and frequency 

for resin manufacturing. 

 

4

 TRIFIDs 31401HRCLSOLDLO, 01013HRCLS1111G, 39401HRCLSWEST7, 53209HRCLS5228N, and 

97210HRCLS3366N. 
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Table 6-2. Summary of 2002 Economic Census Data and Parameters Calculated from these Data for Re

Sites 

2002 Economic Census Data 

Parameters 

Corresponding 

NAICS Description Companies 

Number of 

Establishments 

Production 

Workers 

Aggregate 

Production 

Hours 

Worked 

(1,000 

hours) 

Average 

Production 

Workers 

per Site 

P

(

8 

325199 

All Other Basic Organic Chemical Manufacturing 539 700 40,771 84,466 58 

325211 

Plastics Material and Resin Manufacturing 794 1,059 48,002 99,003 45 

325998 

All Other Miscellaneous Chemical Product and Preparation Manufacturing 1,079 1,223 21,950 44,356 18 

Source: US Census Bureau, 2002a. a – OPPT’s standard default estimate for frequency of exposure is 250 days per year (USEPA, 1992b). b – OPPT’s standard default estimate for duration of exposure is 8 hours per day (USEPA, 1992b).
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6.2 Composite Wood Product Manufacturing

According to an NAICS index entry search3, HWPW, MDF, and PB are divided between 

two industrial categories. HWPW manufacturing is classified under NAICS code 321211 – 

Hardwood Veneer and Plywood Manufacturing, while MDF and PB manufacturing are classified 

under NAICS Code 321219 – Reconstituted Wood Product Manufacturing. 

6.2.1 Potential Exposure Activities 

 The manufacturing processes for composite wood products generally include a 

combination of raw material processing (e.g. log debarking, chipping, screening), wood drying, 

resin application or resin blending, forming, pressing, cooling, cutting, and finishing. Detailed 

process descriptions can be found in the “Assessment of Occupational Exposure to 

Formaldehyde from Composite Wood Products” (USEPA, 2011b). According to this reference, 

workers may be exposed to formaldehyde through one or more of the following activities during 

CWP manufacturing: 

 Dermal contact with resins; 

 Emissions of volatile chemicals from resins during resin application, blending, 

forming, and conveying; 

 Sampling of resinated material prior to pressing; 

 Assembly of the composite wood product after resin application; 

 Hot-pressing; 

 Finishing activities; and 

 Emissions in work areas where stacks of CWPs are cooled, finished, and stored. 

 Exposures to the substitutes that are resin monomers or additives would likely occur 

during similar types of activities, depending on the physical properties of the substitutes 

(volatility, corrosivity, etc.). The level of exposure may also differ depending on the composition 

of the resin, use of the substitute chemical, and the type of engineering controls in place. 

6.2.2 Number of Establishments, Workers, Production Hours, and Work Day Estimates 

 The assessed numbers of sites for the manufacture of the three CWPs are given in Table 

6-3 and Table 6-4. Alternative values for the number of sites are available from the 2002 

Economic Census and are given in Table 6-5. The number of sites reported by the Composite 

Panel Association (CPA) and the U.S. International Trade Commission (USITC) is much lower 

than in the Economic Census data. This is primarily due to the fact that the NAICS codes used 

for the Economic Census data, NAICS code 321211 (hardwood veneer and plywood 

manufacturing) and NAICS 321219 (reconstituted wood product manufacturing), encompass 

additional industrial manufacturing sites outside of HWPW, MDF and PB, while at the same 

time, estimates provided by trade associations do not include non-members or small businesses. 

 

 Similar to the Economic Census analysis done in Section 6.1.2, 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 for composite wood product 

manufacturing industries. As seen in Table 6-5, the frequencies of exposure and production 
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hours per day do not deviate by more than 10 percent from the assumed values for frequency of 

exposure of 250 days per year (assuming a five day work week and 50 weeks per year) and 

duration of exposure of 8 hours per day (assumed as a normal shift duration). Therefore, the 

frequency and production hours per day for HWPW, MDF and PB manufacturing are assumed to 

be 250 days per year, over 8 hours per day, respectively. These values are also assumed to apply 

generally to all workplaces in the CWP lifecycle for the purpose of assessing exposures to 

substitutes.
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Table 6-3. Number of U.S. Hardwood Plywood Mills 

Hardwood Veneer and Plywood Mill Composite Wood Product Type NHardwood Plywood Mills Hardwood Plywood Source: USITC, 2008a. 

Table 6-4. Number of U.S. Reconstituted Wood Product Mills 

Reconstituted Wood Product Mill Type Composite Wood Product Type N

Particleboard Mills Particleboard Medium-Density Fiberboard Mills Medium-Density Fiberboard Source: AWFS, 2009a. Note: The number of MDF mills is a high-end estimate that may include some hardboard mills: the presentation between non-CPA-member MDF and hardboard mills.

Table 6-5. Summary of 2002 Economic Census Data and Parameters Calculated from these Data for CW

Sites 

2002 Economic Census Data 

Parameters 

Corresponding 

NAICS Description Companies 

Number of 

Establishments 

Production 

Workers 

Aggregate 

Production 

Hours 

Worked 

(1,000 

hours) 

Average 

Production 

Workers 

per Site 

A

Pr

D

(a

8 

321211 

Hardwood veneer and plywood manufacturing 303 337 16,861 34,298 50 

321219 

Reconstituted wood product manufacturing 177 282 17,967 38,383 64 

Source: US Census Bureau, 2002a.a – OPPT’s standard default estimate for frequency of exposure is 250 days per year (USEPA, 1992b). b – OPPT’s standard default estimate for duration of exposure is 8 hours per day (USEPA, 1992b).
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6.3 Downstream Product Manufacturing

Downstream product manufacturing may be classified under a number of different 

NAICS codes, as listed in Table 2-2. The NAICS codes were identified by first obtaining 

HWPW, PB, and MDF market data from the Hardwood Plywood and Veneer Association 

(HPVA) and CPA (HPVA, 2009a; CPA, 2008a). The end market data descriptions for HWPW, 

PB, and MDF were then matched to appropriate NAICS codes, based on engineering judgment. 

Downstream product manufacturing comprises an amalgam of different composite wood 

products, which in turn may also be made using different types of resins or adhesives. 

6.3.1 Potential Exposure Activities 

A general description of the manufacturing process is presented below. Detailed 

information on the manufacture of specific downstream products was researched, but was not 

found in the limited data review used for this report. The Office of Enforcement and Compliance 

Assurance (OECA) sector notebook provides a general process description for wood furniture 

and fixtures constructed from raw lumber. Activities involved in downstream product 

manufacturing processes include drying the raw wood; sawing into appropriate sizes, planing, 

and bending (i.e., machining); assembling the wood material into parts; applying veneers; 

sanding; prefinishing (watering, sanding, derosination, bleaching); coating by spraying, brushing, 

or dipping; and finishing (OECA, 1995a). A similar process may be used to produce furniture 

and fixtures using composite wood products (see below for a discussion of activities during 

wood product manufacturing). Solvent-based formulations, hot melts, and polyvinyl acetate are 

common adhesives used in the furniture industry. Therefore, these adhesives may also contain or 

emit formaldehyde substitutes. 

The following representative activities (unit operations) are typically required during 

wood product manufacturing based on survey results of manufacturers (GDNR, 1996a). 

Although the reference does not identify the raw materials used by manufacturers included in the 

survey (e.g. composite wood products or raw lumber), it does state that wood product 

manufacturers may produce different products using similar processes. Therefore, it is possible 

that the cited activities may be applicable to composite wood products in downstream product 

manufacturing. The cited activities include the following: 

 

 Laminating; 

 Assembly; 

 Glues and adhesives; 

 Spray application; 

 Painting and coating; 

 Water-based coating; 

 Solvent-based coating; 

 Staining; 

 Sealing; 

 Water-based cleaning; and 

 Solvent-based coating. 
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These process activities apply to the following downstream product manufacturing 

sectors: millwork, cabinet makers, trusses, prefabricated construction, wood furniture, 

miscellaneous furniture, exhibits and showrooms (GDNR, 1996a). Composite panel products 

typically have decorative finishes or overlays that may be applied at a “sister” facility of the 

primary manufacturer or at an unaffiliated finishing site (CPA, 2009a). However, there is no 

specific NAICS code related to laminating facilities. 

 Although worker activities specific to composite wood products in the downstream 

product manufacturing industries have not been described, workers are potentially exposed to 

formaldehyde and its substitutes from the unfinished composite wood products during storage 

and handling. Process operations where exposure may occur include laminating with decorative 

veneer, cutting, sanding, assembling, and finishing operations. Workers are also potentially 

exposed to emissions from finished, coated or laminated composite wood products, although 

emissions rates from the coated and laminated products are generally lower than those from the 

unfinished products (Battelle, 1996a). 

6.3.2 Number of Establishments, Workers, Production Hours, and Work Day Estimates 

As was done in Sections 6.1.2 and 6.2.2, 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 for composite wood product manufacturing industries, using the 

2002 Economic Census data (U.S. Census Bureau, 2002a). As seen in Table 6-6, the frequency 

of exposure and production hours per day do not deviate from the OPPT default values for 

frequency of exposure of 250 days per year and duration of exposure of 8 hours per day by more 

than 10 percent (USEPA. 1992b). Therefore, the frequency and production hours per day for 

downstream product manufacturing are assessed to be 250 days per year, over 8 hours per day, 

respectively. 
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Table 6-6. Summary of 2002 Economic Census Data and Parameters Calculated from this Data for Pote

Product Manufacturing Sites 

2002 Economic Census Data 

Parame

Correspond

NAICS Description Companies 

Number of 

Establishments 

Production 

Workers 

Aggregate 

Production 

Hours 

Worked 

(1,000) 

Average 

Production 

Workers 

per Site 

321911 Wood window and door manufacturing 1,326 1,443 55,566 106,720 39 321918 Other millwork (including flooring) 2,016 2,071 35,989 69,325 17 321991 

Manufactured home (mobile home) manufacturing 237 416 40,290 75,296 97 

321992 Prefabricated wood building manufacturing 667 739 18,472 36,193 25 337110 

Wood kitchen cabinet and counter top manufacturing 9,457 9,561 100,210 195,053 10 

337121 

Upholstered household furniture manufacturing 1,686 1,911 77,284 145,105 40 

337122 

Non-upholstered wood household furniture manufacturing 3,975 4,114 95,890 184,861 23 

337127 Institutional furniture manufacturing 687 731 24,557 48,944 34 337129 

Wood television, radio, and sewing machine cabinet manufacturing 201 205 2,827 5,767 14 

337211 Wood office furniture manufacturing 547 570 19,230 36,877 34 337212 

Custom architectural woodwork and millwork manufacturing 1,543 1,568 23,080 45,310 15 

337214 

Office furniture (except wood) manufacturing 260 312 24,357 48,918 78 

337215 

Showcase, partition, shelving, and locker manufacturing 1,795 1,891 53,283 102,777 28 

Source: US Census Bureau, 2002a. a – OPPT’s standard default estimate for frequency of exposure is 250 days per year (USEPA, 1992b). b – OPPT’s standard default estimate for duration of exposure is 8 hours per day (USEPA, 1992b).
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6.4 Commercial Use

Workers are potentially exposed to formaldehyde or its substitutes during construction of 

a building, installation of cabinets, vanities, and flooring, or while working within a commercial 

building. However, no general use volumes, number of establishments, employees, employed 

hours or work days estimates were identified. This can be expected as all construction projects 

are different, and there is a wide variation in the sizes and scopes of construction projects. In 

addition, no exposure data during commercial use were identified; therefore commercial use has 

not been assessed in this report. 

 

6.5 Consumer Use

Consumer use, such as home hobbyists, Do-It-Yourselfers (DIY), home occupants, are 

potentially exposed to formaldehyde or its substitutes during construction of a building, 

installation of cabinets, vanities, and flooring, or while working indoors in a home or work shop. 

However, no general use volumes, number of homes, hobbyist or work days estimates were 

identified. This can be expected as DIY projects are different, and there is a wide variation in the 

sizes and scopes of DIY projects. In addition, no exposure data were identified for consumers 

using CWP boards made with substitute chemicals; therefore consumer use has not been 

assessed quantitatively in this report. It is assumed in this report that consumer use does not 

include any manufacture of CWPs, such as gluing wood veneers onto platforms. 
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7.0 EXPOSURE ASSESSMENT BY CHEMICAL

This section assesses occupational exposure and environmental release during each 

relevant life cycle stage. This section is organized according to chemical and life cycle stage. 

Definitions of occupational values are given in Appendix A. 

7.1 Formaldehyde Exposure during UF Resin Manufacturing

This section provides an exposure assessment for formaldehyde during the manufacture 

of UF resin. UF resin manufacturing is classified under NAICS code 325211 – Plastics Material 

and Resin Manufacturing. Table 7-1 presents established occupational exposure limits (OELs) 

for formaldehyde. 

Table 7-1. Occupational Exposure Limits for Formaldehyde 

Source Limit Type Exposure Limita

OSHA PEL

8-hour TWA 0.75 ppm (0.92 mg/m3

) 

15-minute STEL 2 ppm (2.5 mg/m3) 

NIOSH REL 8-hour TWA 0.016 ppm (0.020 mg/m3

) 

ACGIH TLV Ceiling 0.3 ppm (0.37 mg/m3

) 

Sources: OSHA. 2008; NIOSH, 2005; ACGIH, 2009. 

a - 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 (i.e., 1 ppm = 1.229 mg/m3).(NIOSH, 2005) 

7.1.1 Process Description 

Amino resins, such as UF, are usually made via batchwise processes. These reactions are 

controlled through the mole ratio of reactants, catalyst (pH of reaction mixture), reaction time, 

and temperature. Formaldehyde and other reactants are charged to a kettle, adjusted for pH, and 

then heated. After condensation is complete, there are often post-treatment processes to 

evaporate excess water and formaldehyde or add additional urea to decrease the ratio of 

formaldehyde to urea. The final resin syrup product may have formaldehyde concentrations of 

0.59% or less (Fink, 2005a) and can either be loaded for sale to downstream customers or 

processed further into other resin products depending on the application (Kirk-Othmer, 2002a). 

Feedstock formaldehyde for UF resin production is typically in the form of formalin, an aqueous 

mixture with formaldehyde percentages ranging from 37 to 50 percent. (Fink, 2005a) 

During the manufacture of amino resins, every effort is made to recover and recycle the 

raw materials; however, there may still be some losses of formaldehyde during tank or reactor 

venting (Kirk-Othmer 2002a). A representative process flow diagram of UF resin manufacturing 

is provided below in Figure 7-1; although, the figure also includes optional steps of molding 

compound manufacture and spray-dried resin manufacture after the resin syrup is formed. No 

information was found on engineering controls or PPE used when handling formaldehyde during 

UF resin manufacturing.
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Figure 7-1. Process flow diagram for UF resin manufacturing (Kirk-Othmer, 2002a) 
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7.1.2 Exposure Assessment for Formaldehyde in UF Resin Manufacturing 

Inhalation monitoring data for formaldehyde specifically during UF resin manufacturing 

were not found. The most recent surrogate data found in the OSHA IMIS database was under 

NAICS code 325211 (Plastics Material and Resin Manufacturing), which would include UF 

resin manufacturing facilities. Table 7-2 presents this surrogate inhalation monitoring data from 

the OSHA IMIS database. Note that the monitored concentration in Table 7-2 does not exceed 

the OSHA PEL of 0.75 ppm (8-hr TWA). 

Table 7-2. Surrogate Inhalation Monitoring Data from OSHA IMIS Database used to 

represent Formaldehyde Concentrations during UF Resin Manufacturing 

Industry 

Worker Activity 

Description 

Number 

of Sites 

Monitored 

Monitored 

Formaldehyde 

Concentration 

(ppm) 

Monitored 

Formaldehyde 

Concentration 

(mg/m3)

a

Monitoring 

Type Year 

Concentration 

Level / # of 

Data Points 

Plastics 

Material and 

Resin 

Manufacturing 

(NAICS 

325211) 

Lead Man 1 0.064 0.079 Personal 

(TWA) 1980 1 Data Point 

Source: OSHA, 2010. 

a - 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 (i.e., 1 ppm = 1.229 mg/m3).(NIOSH, 2005) 

Table 7-3 presents the estimated ADC and LADC of formaldehyde during UF resin 

manufacturing. As discussed in Section 6.1.2 for general resin manufacturing, the frequency of 

exposure is assessed to be 250 days per year and the duration of exposure is assessed to be 8 

hours per day. 

Table 7-3. Estimated Average Daily Concentrations for Data Representing Formaldehyde 

during UF Resin Manufacturing 

Industry 

Worker Activity 

Description 

Concentration 

Level 

Monitored 

Formaldehyde 

Concentration 

(mg/m3) 

Average Daily 

Concentration 

(μg/m3) 

Lifetime 

Average Daily 

Concentration 

(μg/m3) 

Plastics Material 

and Resin 

Manufacturing 

(NAICS 325211) 

Lead Man 1 Data Point 0.079 18 10 

The dermal model used for estimates in this report could not be adjusted to account for 

the higher volatility of the formalin raw material containing formaldehyde - see Section 3.2.2 for 

an explanation. However, free formaldehyde may exist at about 0.59% or less in the non-volatile 

resin (Fink, 2005a). Based on this concentration and the EPA/OPPT 2-Hand Dermal Contact 

with Liquid Model (see Section 3.2.2), the dermal exposure during activities where workers 

contact or handle liquid UF resin product is estimated to be 0.05 to 0.15 mg/kg/day 

formaldehyde. 
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7.1.3 Uncertainty in Exposure Assessment 

Because no data were available for formaldehyde in UF resin manufacturing surrogate 

data were used. However, the extent that this surrogate data is actually representative of 

formaldehyde in UF resin manufacturing is unknown. Additionally, there is only one data point 

available, making it difficult to characterize the data. Overall data limitations and uncertainties 

are discussed in Section 5.0. 

7.1.4 Environmental Releases of Formaldehyde during UF Resin Manufacturing 

Table 7-4 presents releases of formaldehyde under NAICS code 325211 (Plastics 

Material and Resin Manufacturing) reported to the TRI for reporting year 2008. In 2008, the 

majority of releases were sent for off-site water treatment, with the remainder split between air, 

landfill, or incineration. 
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Table 7-4. Environmental Releases of Formaldehyde during Plastics Material and Resin Manufacturing as 

Reporting Year 2008 

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) Off-Site Transfers for Release (lb) 

Stack 

Air 

Fugitive 

Air 

Total 

Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

325211 

(64 sites) 

Plastics Material and Resin Manufacturing 205,136 44,885 250,021 7,687 289,757 547,465 117,780 13,984 131,764 

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 and re

December 2009. These data only include quantities that are released or transferred off site for treatment in wastewater and incineration unitssent to on- and off-site waste management such as recycling and reuse. a - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). 
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7.2 Methanol

Methanol is used to manufacture formaldehyde, which is subsequently used in the 

production of UF resins for use in the CWPs industry. Feedstock formaldehyde for UF resin 

production is typically in the form of formalin, an aqueous mixture with formaldehyde 

percentages ranging from 37 to 50 percent (Fink, 2005a). Formalin may also contain methanol in 

varying concentrations, although typical concentrations are approximately 10 percent (Kiernan, 

2000a). This can result in exposure to methanol during the UF resin manufacturing process. 

Residual methanol in the resin may lead to additional exposures during downstream composite 

wood product production and subsequent industrial and commercial use. Table 7-5 lists 

established OELs in the U.S. 

Table 7-5. Occupational Exposure Limits for Methanol (CASRN 67-56-1) 

Source Limit Type Exposure Limit 

OSHA PEL 8-hour TWA 200 ppm (260 mg/m3

) 

NIOSH RELa

TWA for up to a 10-hour workday 

and a 40-hour workweek 200 ppm (260 mg/m3

) 

Short-term exposure limit 250 ppm (325 mg/m3). 

ACGIH TLVa, b

TWA for up to an 8-hour workday 

and a 40-hour workweek 200 ppm (260 mg/m3

) 

Short-term exposure limit 250 ppm (325 mg/m3) 

Sources: OSHA, 2006; NIOSH, 2005; ACGIH, 2009. 

a – NIOSH and ACGIH also assign a "Skin" notation to methanol. 

b – The ACGIH TLV for methanol is based, among other things, upon the potential for sensitization and meant to 

protect workers from induction of this effect. 

This section provides the exposure assessment for methanol during the following life 

cycle stages: UF resin manufacturing, CWP manufacturing, downstream product manufacturing, 

and commercial/consumer use. 

7.2.1 Manufacture of UF Resin 

The manufacture of UF resins is typically achieved in basic stages starting with 

methylolation, then condensation, and finally post treatment. This is typically done in a batch 

process and can involve several types of processing equipment (Fink, 2005a). 

Process Description 

The UF manufacturing process has been previously described in Section 7.1. A modifiedUF resin was made for PB by adding extra methanol to the process (capping the methylol urea as 

methyl ethers), thereby reducing the formaldehyde emissions (USEPA, 2011c). No specific 

information was found in the literature concerning the amount of methanol added, nor was any 

information found about where in the process the methanol is added. 
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The NIOSH international chemical safety card for methanol recommends the use of 

protective gloves, protective clothing, safety goggles, and local exhaust ventilation when 

handling methanol (NIOSH, 1994a). Specific PPE and engineering controls regarding methanol 

use during UF resin manufacture were not available. 

Exposure Assessment for Methanol in the Manufacture of UF Resin 

Inhalation monitoring data for methanol exposures during UF resin manufacturing were 

not found. Additionally, surrogate data were not found in the OSHA IMIS database for any 

relevant NAICS codes. The OECD SIDS report for methanol indicated that the major sources of 

methanol include: 1) production, storage, and use as a solvent, 2) use as a chemical intermediate, 

and 3) as a trace constituent from vehicle engines (OECD, 2004a). The OECD SIDS report 

presented the 95th percentile value of general inhalation monitoring data taken from several 

workplaces at BASF AG in Ludwigshafen, Germany, but did not specifically present monitoring 

data for UF resin manufacturing. Table 7-6 presents the general workplace inhalation monitoring 

data that were used as surrogate data for UF resin manufacturing processes. 

Table 7-6. Surrogate Inhalation Monitoring Data from OECD used to represent Methanol 

Concentrations during UF Resin Manufacturing 

Type of Monitoring Dates Worker Activities 

Number of 

Samples Values (mg/m3) 

8-hr TWA 1998-2003 

Production, processing, 

quality control, pilot 

plant, research 

laboratories, filling 

stations, etc. 

950 32 

(95th percentile)a

Source: OECD, 2004a. 

a – The OECD SIDS report only provided the 95th percentile data. 

Table 7-7 presents the calculated ADC and LADC (see Section 3.2.1). Note that the 95th

percentile concentration provided by OECD is well below the OSHA PEL of 260 mg/m3

. As 

discussed in Section 6.1.2 for general resin manufacturing, the frequency of exposure is assessed 

to be 250 days per year and the duration of exposure is assessed to be 8 hours per day. 

Table 7-7. Estimated Average Daily Concentrations for Data Representing Methanol 

during UF Resin Manufacturing 

Industry 

Worker Activity 

Description 

Concentration 

Level 

Monitored 

Methanol 

Concentration 

(mg/m3) 

Average Daily 

Concentration 

(μg/m3) 

Lifetime 

Average Daily 

Concentration 

(μg/m3) 

Unknown 

Production, 

processing, quality 

control, pilot plant, 

research 

laboratories, filling 

stations, etc. 

95th percentile (of 

950 samples) 32 7,300 4,200 

The dermal model used for estimates in this report could not be adjusted to account for 

the higher volatility of methanol - see Section 3.2.2 for an explanation. 
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Uncertainty in Exposure Assessment 

There is a lack of monitoring data for methanol during UF resin manufacturing. The 

OECD SIDS data provides one data point representing a 95th percentile of 950 data points for 

methanol exposures, but does not specifically target UF resin manufacturing. Additionally, these 

samples were taken from areas in Germany, where the conditions may not be indicative of the 

conditions in the U.S. However, these samples were taken in industrial settings and may provide 

some insight into methanol exposures at UF resin manufacturing plants. Overall data limitations 

and uncertainties are discussed in Section 5.0. 

Environmental Releases of Methanol during UF Resin Manufacturing 

 Table 7-8 presents releases of methanol under NAICS code 325211 (Plastics Material and 

Resin Manufacturing) reported to the TRI for reporting year 2008. The main media of release is 

off-site incineration, followed by off-site water treatment. 
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Table 7-8. Environmental Releases of Methanol during Plastics Material and Resin Manufacturing Re

Reporting Year 2008 

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) Off-Site Transfers for Release (lb) 

Stack 

Air 

Fugitive 

Air Total Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

325211 

(111 sites) 

Plastics Material and Resin Manufacturing 1,824,256 1,622,898 3,447,155 54,452 1,748,854 5,250,461 2,835,660 46,413 2,882,073 

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 an

December 2009. These data only include quantities that are released or transferred off site for treatment in wastewater and incineration quantities sent to on- and off-site waste management such as recycling and reuse. a - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). 
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7.2.2 Methanol in CWP Manufacture 

Methanol may be available for exposure during the use of UF resins in CWP manufacture 

and is expected to be volatilized during the curing process (USEPA, 2011c). 

Process Description 

Manufacture of composite wood products is expected to be identical to the general CWP 

manufacturing process description described in Section 6.2.1. No data on engineering controls 

and PPE during the use of methanol in CWP manufacturing were found. 

Exposure Assessment for Methanol in CWP Manufacturing 

Because of volatilization of methanol during the curing process, inhalation exposures are 

expected to be higher during CWP manufacturing than during the UF resin manufacturing. 

However, no inhalation monitoring data were found for methanol during CWP manufacturing. 

Therefore, formaldehyde monitoring data were used as a model to estimate methanol exposures, 

because both have similar vapor pressures. 

In Section 7.1.2, a formaldehyde air concentration of 79 μg/m3 was assessed during the 

UF resin manufacturing process. EPA’s exposure assessment of formaldehyde in CWPs 

presented formaldehyde air concentrations up to 1,900 μg/m3

 at potential CWP manufacturing 

sites (USEPA, 2011b). The formaldehyde concentration during CWP manufacturing is 

approximately 24 times higher than during UF resin manufacturing. 

Section 7.2.1 assessed a methanol concentration of 32 mg/m3 during UF resin 

manufacturing. Applying the multiplier of 24, calculated from the increase in formaldehyde 

concentrations, results in an estimated methanol concentration of 777 mg/m3. Note that this 

calculated is well above the OSHA PEL of 260 mg/m3

. Therefore, the OSHA PEL value is used 

as the “what-if” type estimate. Table 7-9 presents the calculated ADC and LADC for methanol 

(see Section 3.2.1). 

Also as discussed in Section 6.2.2 for composite wood product manufacturing, the 

frequency of exposure is assessed to be 250 days per year and the duration of exposure is 

assessed to be 8 hours per day. 

Table 7-9. Estimated “What-If” Average Daily Concentrations of Methanol during CWP 

Manufacturing, based on the OSHA PEL 

Source Limit Type 

Methanol Exposure 

Limit (mg/m3) 

Average Daily 

Concentration 

(μg/m3) 

Lifetime Average 

Daily Concentration 

(μg/m3) 

OSHA PEL 8-hour TWA 260 59,000 34,000 

The dermal model used for estimates in this report could not be adjusted to account for 

the higher volatility of methanol - see Section 3.2.2 for an explanation. 
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Uncertainty in Exposure Assessment 

There is a lack of monitoring data for methanol during CWP manufacturing. Inhalation 

exposures estimates were assume to be below the OSHA PEL, which is considered as a “what-if” 

type estimate. Dermal exposures could not be estimated, due to the volatile nature of methanol. 

Overall data limitations and uncertainties are discussed in Section 5.0. 

Environmental Releases of Methanol during CWP Manufacturing 

Table 7-10 presents releases of methanol during NAICS codes 321211 and 321219 

(Hardwood Veneer and Plywood Manufacturing and Reconstituted Wood Product 

Manufacturing, respectively) reported to the TRI for reporting year 2008. The majority of 

releases are to stack air in both industries.
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Table 7-10. Environmental Releases of Methanol during CWP Manufacturing Reported in TRI for Rep

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) Off-Site Transfers for Release (lb) 

Stack 

Air 

Fugitive 

Air Total Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

321211 

(2 sites) 

Hardwood Veneer and Plywood Manufacturing 43,449 6,332 49,781 0 0 49,781 0 0 0 

321219 

(73 sites) 

Reconstituted Wood Product Manufacturing 4,542,783 103,440 4,646,223 390 18 4,646,631 565 0 565 

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 an

December 2009. These data only include quantities that are released or transferred off site for treatment in wastewater and incineration quantities sent to on- and off-site waste management such as recycling and reuse. a - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). 
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7.2.3 Downstream Product Manufacture and Commercial/ Consumer Use 

Methanol is expected to be volatilized during curing in the CWP manufacture process 

(USEPA, 2011c). Therefore, exposures and releases of trace residual methanol are expected to be 

negligible or non-quantifiable for downstream product manufacturing and commercial use. 

Since consumer use would be in this set of life cycle stages, consumer exposure is expected to be 

negligible as well. 
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7.3 Melamine

The major demand for melamine (CASRN 108-78-1) in the U.S. is for surface coatings 

and laminating resins (Mannsville, 2006a; Kirk-Othmer, 2002a). Melamine currently does not 

have any occupational exposure limits established by OSHA, NIOSH, or ACGIH (USEPA, 

2009d). The vapor pressure of melamine is 4.7 x 10-8 Pa (3.5 x10-10 mm Hg) at 20 degrees 

Celsius (OECD, 1998a). 

This section provides the complete exposure assessment for melamine during the 

following life cycle stages: MUF and other melamine-based resin manufacturing, CWP 

manufacturing, downstream product manufacturing, and commercial/ consumer use. 

7.3.1 Manufacture of MUF and Other Melamine-Based Resins 

Melamine-based resins can be used for applications requiring composite wood products 

with low formaldehyde emissions. Melamine-fortified resins are also used in applications 

requiring high mechanical strength and low thickness swelling because pure UF resins are too 

weak for these purposes. The content of melamine in these resins can vary depending on required 

formaldehyde emissions, as well as the required properties of the board (Kirk-Othmer 2005a). 

Exposures to melamine during MUF manufacture versus other melamine-based resins cannot be 

distinguished with the available information; therefore all melamine-based resins are assessed 

together. General melamine resin manufacturing is classified under NAICS code 325211 – 

Plastics Material and Resin Manufacturing. 

Process Description 

Co-condensation of MF resins with urea, phenols, and other components is possible in 

many ways, although two independent, interpenetrating networks may be formed instead. The 

production of MUF resins of various melamine contents can follow various paths (Kirk-Othmer, 

2005a): 

1. Direct co-condensation of melamine, urea, and formaldehyde in a multistep reaction 

with varying sequences of addition of the components; 

2. Direct mixing of an MF resin with a UF resin; 

3. Addition of melamine in various forms (pure melamine, MF/MUF-powder resin) to a 

UF resin during the application of the resin; or 

4. Melamine can also be added in the form of melamine salts, such as acetates, 

formiates, or oxalates, which decompose in the aqueous resin mix at higher 

temperatures. It has been reported that using this procedure with melamine salts, the 

amount of melamine needed is much lower than in other MUF resins. 

No information on engineering controls or PPE were found. 

Exposure Assessment for Melamine in Resin Manufacturing 
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No inhalation monitoring data were found for melamine in resin manufacturing settings, 

nor were surrogate monitoring data available in the OSHA IMIS database. The OECD SIDS 

report for melamine included inhalation data for melamine processing, indicating that a 

concentration of 0.1 to 1.14 mg/m3 of pure melamine particulate was monitored in two melamine 

processing plants (OECD, 1998a). Table 7-11 assesses melamine inhalation exposures using the 

exposure information from the OECD SIDS report. 

Table 7-11. Estimated Average Daily Concentrations of Surrogate Inhalation Monitoring 

Data from OECD used to represent Melamine Concentrations during Melamine-Based 

Resin Manufacturing 

Industry Worker Activities 

Concentration of 

Melamine Particulate 

in Air (mg/m3) 

Average Daily 

Concentration 

(μg/m3) 

Lifetime Average 

Daily 

Concentration 

(μg/m3) 

Melamine Processing Unknown 0.1 – 1.14 23-260 13-150 

Source: OECD, 1998a 

Dermal exposures were calculated using the EPA/OPPT 2-Hand Dermal Contact with 

Solids Model, which estimates a dermal exposure of <44 mg/kg/day (see Section 3.2.2) for 

unloading of solids. EPA assumes up to 100% by weight melamine in solids, resulting in up to 

44 mg/kg/day exposure to melamine. 

As discussed in Section 6.1.2 for general resin manufacturing, the frequency of exposure 

is assessed to be 250 days per year and the duration of exposure is assessed to be 8 hours per 

day. 

Uncertainty in Exposure Assessment 

The only available data are from a 1998 OECD document and may be outdated or not 

applicable to U.S. manufacturing facilities. In addition, the description of “melamine processing” 

is vague and may not refer to resin manufacturing. Overall data limitations and uncertainties are 

discussed in Section 5.0. 

Environmental Releases of Melamine from Resin Manufacturing 

 Melamine was not on the TRI list of regulated chemicals in 2008, nor were any additional 

sources of release data found. Therefore, no release estimates are presented. 

7.3.2 Melamine in CWP Manufacturing 

The use of melamine resins in CWP manufacturing are expected to be similar to the 

process described in Section 6.2.1. Additional details are described below. 

Process Description 

In gluing, the adhesive must not saturate the veneers or wood chips, but must remain on 

the surface of the chips or between the plies; therefore, the adhesives are generally of high 

viscosity. Thickeners and extenders, such as powdered pecan shells and wheat flour, are also 
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Page 41 

often used. Rapid cures may be achieved by using microwave radiation. Hot pressing may be 

conducted in a hydraulic press comprising a large number of steam-heated platens usually 5 

centimeters thick. Pressures usually range from 1 to 2 MPa (150 to 300 psi). Hot press 

temperatures for urea and melamine–urea are usually 115 to 1,328 degrees Celsius (KirkOthmer, 2002a). Melamine content in the resins can vary between a few percent to more than 

30% (Kirk-Othmer, 2005a). Occupational exposure may occur during mixing, unloading or 

application of the resin. No information on engineering controls or PPE were found. 

Exposure Assessment for Melamine in CWP Manufacturing 

No workplace monitoring data were available for melamine in CWP manufacturing. The 

vapor pressure of melamine is 5 x10-7 mmHg at 25 degreesCelsius, and melamine is a 

component of a liquid resin; inhalation exposures from volatilization are expected to be 

negligible due to its low vapor pressure. 

As stated in the process description, melamine may comprise more than 30% of the resin 

(Kirk-Othmer, 2005a). Based on this concentration and the EPA/OPPT 2-Hand Dermal Contact 

with Liquid Model (see Section 3.2.2), the maximum dermal exposure is expected to be from 2.5 

to 7.6 mg/kg/day melamine. 

Also as discussed in Section 6.2.2 for composite wood product manufacturing, the 

frequency of exposure is assessed to be 250 days per year and the duration of exposure is 

assessed to be 8 hours per day. 

 

Uncertainty in Exposure Assessment 

Literature indicates that the melamine content can vary between a few percent to more 

than 30%. A “typical” melamine concentration is unknown; therefore the estimated dermal 

exposures may be overestimated or underestimated. .Overall data limitations and uncertainties 

are discussed in Section 5.0. 

Environmental Releases of Melamine from CWP Manufacturing 

Melamine was not on the TRI list of regulated chemicals in 2008. Additional sources of 

release data were not found; therefore, no release estimates are presented. 

7.3.3 Melamine Resins in Downstream Product Manufacturing and Commercial/ Consumer 

Use 

The processes for downstream product manufacturing and commercial use are expected 

to be identical to the processes described in Section 6.3.1 and 6.4. No workplace monitoring data 

were found for melamine in downstream product manufacturing or commercial use. Melamine 

will likely be entrained in cured resin; therefore, inhalation exposures from volatilization of 

residual melamine are expected to be negligible due to its low vapor pressure, and dermal 

exposures cannot be quantified. Consumer exposure is expected to be negligible as well, for the 

same reasons as given above. 
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7.4 Epichlorohydrin

Epichlorohydrin is supplied commercially as a pure liquid and is primarily used as an 

intermediate in the manufacture of a variety of epoxy resins. Most commonly, it is reacted with 

bisphenol-A to produce bisphenol-A diglycidal ether, a liquid epoxy resin used in a variety of 

adhesive and coating applications. Epichlorohydrin is also used in the synthesis of glycerin, wet 

strength resins, and epichlorohydrin elastomers. Table 7-12 summarizes the current OELs for 

epichlorohydrin established by OSHA, NIOSH, and ACGIH. 

Table 7-12. Occupational Exposure Limits for Epichlorohydrin 

Source Limit Type Exposure Limitd

OSHA PELa 8-hour TWA 5 ppm (19 mg/m3

) 

NIOSH RELb Ca 

ACGIH TLVc TWA for a normal 8-hour workday 

and a 40-hour workweek. 0.5 ppm (1.9 mg/m3

) 

Source: OSHA, 2006; NIOSH, 2005; ACGIH, 2009. 

a - The OSHA PEL also bears a "Skin" notation, which indicates that the cutaneous route of exposure (including 

mucous membranes and eyes) contributes to overall exposure. 

b - NIOSH considers epichlorohydrin to be a carcinogen. NIOSH policy for RELs for most carcinogens, including 

epichlorohydrin, were non-quantitative values labeled "lowest feasible concentration (LFC)". See Appendix A - 

NIOSH Potential Occupational Carcinogens (http://www.cdc.gov/niosh/npg/nengapdxa.html) for more details. 

c - ACGIH also assigns a "Skin" notation to epichlorohydrin. 

d - The concentration in mg/m3

 was calculated from the provided concentration in ppm by multiplying the 

concentration in ppm by 3.78 mg/m3

/ppm (i.e., 1 ppm = 3.78 mg/m3).(NIOSH, 2005)

 Wet-strength resins such as polyamine epichlorohydrin (PAE) are typically used in the 

paper industry as an additive to enhance the wet-strength of paper products. A particular PAE 

resin product produced by Hercules Incorporated is currently being used in the formulation of 

PureBond, a formaldehyde-free wood adhesive used by Columbia Forest Products in the 

production of HWPW. Information from Hercules provided in a University of Massachusetts 

study on formaldehyde alternatives suggests that epichlorohydrin is fully consumed in the 

reaction to make the PAE resin (UMass, 2006a). Based on this information, it is assumed that 

occupational exposures to epichlorohydrin will be negligible during all downstream processes 

after PAE resin production including the formulation of PureBond, the use of PureBond in 

HWPW manufacturing, and the subsequent downstream and commercial/ consumer use of the 

products. 

This section provides the complete exposure assessment for epichlorohydrin during the 

following life cycle stages: polyamine epichlorohydrin resin manufacturing, PureBond 

manufacturing, HWPW manufacturing, downstream product manufacturing and commercial/ 

consumer use. 

7.4.1 Manufacture of Polyamine Epichlorohydrin Resin 

PAE resins are primarily used as a coating for paper fibers to enhance its wet-strength 

properties. However, Columbia Forest Products uses a PAE resin manufactured by Hercules 
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Incorporated to formulate PureBond, a soy-based wood adhesive. As stated previously in Section 

6.1, PAE manufacturing may fall under NAICS codes 325211 - Plastics Material and Resin 

Manufacturing, 325199 – All Other Basic Organic Chemical Manufacturing, or 325998 - All 

Other Miscellaneous Chemical Product and Preparation Manufacturing, based on TRI reporting 

by Hercules, Inc. 

Process Description 

The manufacture of PAE resins involves a two-step reaction sequence. The first reaction 

involves the condensation of a dibasic acid with diethylene triamine to yield a water-soluble 

polyamide. The available amine groups are then alkynated with epichlorohydrin to form an 

amino chlorohydrin. These amino chlorohydrins can undergo crosslinking between polymer 

chains or stabilize by forming a cyclic structure (NZIC, 2008a). The PAE resin manufactured by 

Hercules Incorporated is performed in a batch process where all of the epichlorohydrin is fully 

consumed in the irreversible reaction to form the resin (UMass, 2006a). Based on this 

information, occupational exposures are most likely to occur during the unloading of the 

epichlorohydrin into the reactor. Additional exposures are possible from sampling of the reaction 

for completion and during container and equipment cleaning activities where residual 

epichlorohydrin may be present. 

Information on the specific use of PPE and engineering controls during the manufacture 

of PAE resins was not available in the reviewed literature. A product stewardship manual for the 

safe handling and storage of epichlorohydrin was developed by Dow Chemical for its customers. 

The manual states that in all operations involving epichlorohydrin, workers should wear 

chemical goggles, safety hats, impervious boots, gloves, and outer clothing. Table 7-13 contains 

a summary of PPE information provided by Dow Chemical. The use of closed process systems, 

ventilation, and automatic sampling is also stressed in the manual (Dow, 2007a). 

Table 7-13. PPE Considerations during Use of Epichlorohydrin 

Item Considerations 

Clothing, Gloves, Boots

Boots - Butyl rubber appears to provide the best inherent barrier properties. 

Laminate constructions containing SARANTM Resins or polyvinyl alcohol can be 

designed to provide various levels of barrier. 

Nitrile and neoprene rubber are penetrated more readily. 

Respiratory Protection

Where low short-term exposures are anticipated, use full face respirator with 

organic vapor or organic vapor/acid gas cartridges. 

For unknown concentrations to those substantially above the occupational exposure 

guide, use positive pressure supplied air or self-contained, positive pressure 

breathing apparatus (SCBA). 

For emergency situations use self-contained, positive pressure breathing apparatus.

Eye Protection

Chemical workers’ goggles, if splashing is unlikely to occur. 

Full-face shield if splashes may occur. 

Alternatively, a full-face respirator can be used. 
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Source: Dow, 2007a. 

Exposure Assessment for Epichlorohydrin in PAE Resin Manufacturing 

Table 7-14 presents inhalation monitoring data from the OSHA IMIS database, which 

specifically indicates that the worker activity is for a Kymene operator. Kymene is the PAE resin 

used in the formulation of PureBond. The data point is from 1986, which does not meet the data 

preference criteria described in Appendix B. However, this concentration is similar to a 

maximum concentration reported in a University of Massachusetts study of 0.15 ppm, which was 

measured in 1978 from Hercules facilities that manufacture Kymene (UMass, 2006a). The values 

reported from OSHA IMIS and from the Hercules facilities do not exceed the OSHA PEL of 5 

ppm. 

Table 7-14. Inhalation Monitoring Data from OSHA IMIS Database for Epichlorohydrin 

during PAE Production 

Industry 

Worker 

Activity 

Description 

Number 

of Sites 

Monitored 

Monitored 

Epichlorohydrin 

Concentration 

(ppm) 

Monitored 

Epichlorohydrin 

Concentration 

(mg/m3)

a

Monitoring 

Type Year 

Concentration 

Level / # of 

Data Points 

All Other 

Basic Organic 

Chemical 

Manufacturing 

(NAICS 

325199) 

Kymene 

Operator 1 0.2 0.76 Personal (TWA) 1986 1 Data Point 

Source: OSHA, 2010. 

a - The epichlorohydrin concentration in mg/m3

 was calculated from the provided concentration in ppm by 

multiplying the concentration in ppm by 3.78 mg/m3/ppm (NIOSH, 2005) 

Table 7-15 estimates the ADC and LADC of epichlorohydrin during PAE resin 

manufacturing, based on monitoring data from the OSHA IMIS Database. As discussed in 

Section 6.1.2 for general resin manufacturing, the frequency of exposure is assessed to be 250 

days per year and the duration of exposure is assessed to be 8 hours per day. 

Table 7-15. Estimated Average Daily Concentrations of Epichlorohydrin during 

Manufacture of PAE Resin 

Industry 

Worker Activity 

Description 

Concentration 

Level 

Monitored 

Epichlorohydrin 

Concentration 

(mg/m3) 

Average Daily 

Concentration 

(μg/m3) 

Lifetime 

Average Daily 

Concentration 

(μg/m3) 

All Other Basic 

Organic Chemical 

Manufacturing 

(NAICS 325199) 

Kymene 

Operator 1 Data Point 0.76 170 99 

The dermal model used for estimates in this report could not be adjusted to account for 

the higher volatility of epichlorohydrin - see Section 3.2.2 for an explanation. 
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Uncertainty in Exposure Assessment 

There were limited exposure monitoring data available for the use of epichlorohydrin 

during PAE manufacturing. Only one data point prior to reporting year 1986 was available, 

which may not be applicable to or representative of present industrial conditions. In addition, it is 

unclear whether the only use of epichlorohydrin at this facility is to manufacture PAE resin. 

Overall data limitations and uncertainties are discussed in Section 5.0. 

Environmental Releases of Epichlorohydrin during PAE Manufacturing 

Table 7-16 presents releases of epichlorohydrin during NAICS codes 325211 and 325998 

(Plastics Material and Resin Manufacturing and All Other Miscellaneous Product and 

Preparation Manufacturing, respectively) reported to the TRI for reporting year 2008. 
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Table 7-16. Environmental Releases of Epichlorohydrin during Plastics Material and Resin Manufactur

325211) and All Other Miscellaneous Chemical Product and Preparation Manufacturing (NAICS Code 3

TRI for Reporting Year 2008 

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) Off-Site Transfers for Release (lb) 

Stack 

Air 

Fugitive 

Air Total Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

325211 

(13 sites) 

Plastics Material and Resin Manufacturing 9,086 58,957 68,043 1,413 199 69,655 1 0 1 

325998 

(13 sites) 

All Other Misc. Chem. Product and Preparation Manufacturing 2,000 7,419 9,419 0 429,734 439,153 66 69 135 

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 an

December 2009. These data only include quantities that are released or transferred off site for treatment in wastewater and incineration quantities sent to on- and off-site waste management such as recycling and reuse. a - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). 
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7.4.2 Manufacture of PureBond, HWPW, Downstream Product Manufacture, and 

Commercial/ Consumer Use 

Hercules Incorporated uses PAE in the formulation of PureBond. Based on the University 

of Massachusetts study, epichlorohydrin is expected to be fully consumed in the reaction to 

produce PAE resin (UMass, 2006a). Therefore, exposures and releases are expected to be 

negligible or non-quantifiable downstream of PAE resin manufacturing. Consumer exposure is 

expected to be negligible as well, for the same reasons as given above. 
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7.5 Polymethylene Diphenyl Diisocyanate (pMDI)

Methylene diphenyl diisocyanate (MDI) is the general name for a set of isomers with the 

empirical formula C15H10N2O2. MDI isomers exist as 4,4’-MDI, 2,4’-MDI, and 2,2’-MDI. The 

4,4’-MDI isomer is considered the pure form of MDI and most easily isolated during the 

manufacturing process. Manufactured MDI typically comprises over 97 percent pure MDI and 3 

percent or less of the other isomeric forms and exists as a white, waxy solid at room temperature. 

The polymeric form of MDI (pMDI) also exists as a co-product during the manufacture of 

monomeric MDI. It exists as a dark viscous liquid at room temperature and typically comprises 

40 to 50 percent 4-4’-MDI, 2.5 to 4 percent 2-4’-MDI, 0.1 to 0.2 percent 2,2’-MDI, and 40 to 50 

percent homologues. (EU, 2005b) Because MDI is a significant component of pMDI, both MDI 

and pMDI are examined in this report. Table 7-17 presents the OELs for MDI; there are no 

OELs established for pMDI. 

Table 7-17. Occupational Exposure Limits for MDI and pMDI 

Source Type 

MDI 

CASRN 101-68-8 

pMDI 

CASRN: 9016-87-9 

OSHA PEL Ceiling 0.2 mg/m3

 (0.02 ppm) None currently listed. 

NIOSH REL

TWA for up to a 10-hour 

workday during a 40-hour 

workweek

0.05 mg/m3 (0.005 ppm) 

None currently listed. 

Ceiling 

(any 10-minute period) 0.2 mg/m3

 (0.02 ppm) 

ACGIH TLVa

TWA for a normal 8-hour 

workday and a 40-hour 

workweek.

0.05 mg/m3

 (0.005 ppm) None currently listed. 

Source: OSHA, 2006; NIOSH, 2005; ACGIH, 2009. 

a - The ACGIH TLV for MDI is based, among other things, upon the potential for sensitization and meant to protect 

workers from induction of this effect. 

pMDI is used in the composite wood products industry in the production of various 

products including oriented strand board (OSB), particleboard (PB), and medium-density 

fiberboard (MDF). It can be used as a component in binders added to wood chips before pressing 

into boards or used as an adhesive to adhere multiple wood boards together (EU, 2005a). MDI is 

not typically used in HWPW. 

This section provides the assessment for pMDI during the following life cycle stages: 

pMDI resin manufacturing, CWP manufacturing, downstream product manufacturing and 

commercial/ consumer use. 

The EU Risk Assessment for MDI indicated that worker exposures are primarily 

mitigated by the use of closed processing systems. Additionally, general PPE includes chemicalprotective suits, gloves, aprons, safety shoes, overalls and self-contained breathing protection if 

no adequate local exhaust is installed. The risk assessment also indicated that eye protection 

should be worn at all times when handling and operating machines using MDI (EU, 2005a). 
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7.5.1 pMDI Resin Manufacture 

MDI and pMDI are manufactured using the same general process, which yields a crude 

mixture of MDI isomers and pMDI that requires subsequent separation processes to yield the 

desired products. MDI and pMDI (diisocyanate) resin manufacturing are classified under NAICS 

code 325211 – Plastics Material and Resin Manufacturing. 

Process Description 

The production of MDI and pMDI involves a three-step process. The first step involves 

the production of methylenedianiline (MDA). MDA is synthesized by the reaction of aniline with 

formaldehyde in the presence of hydrochloric acid to yield an isomeric mixture of 4,4’-MDA, 

2,4’-MDA, and 2,2’-MDA. In the next step of the process, the MDA product is charged to a 

reactor with phosgene where the MDA is converted to a mixture of pure MDI, pMDI, and mixed 

MDI isomers. The composition can be manipulated based on adjustment of process conditions. 

The final step involves the separation of the various components to pure, crude, and polymeric 

MDI product for various uses. The separation can be done through techniques such as vacuum 

distillation or crystallization (EU, 2005a). 

The manufacture of MDI and pMDI are done in closed systems and may be automatically 

controlled from an outside central control room. The final MDI products are stored in tanks and 

transferred to use facilities via pipelines or road tanks. Occupational exposures may occur 

intermittently through various routine worker activities such as sampling, filter changing, 

connection and disconnection of pipelines, drumming or product, loading and unloading of road 

tankers, equipment cleaning, and accidental spill cleanup (EU, 2005a). 

Exposure Assessment from MDI/pMDI in pMDI Resin Manufacturing 

The EU Risk Assessment for MDI provided some workplace measurements from the 

chemical industry for MDI/ pMDI manufacturing. The measurements from 1994 to 1996 range 

between 0.01 and 0.2 mg/m3

, as summarized in Table 7-18. 

Table 7-18. Inhalation Monitoring Data from EU Risk Assessment for MDI/ pMDI 

Concentrations during pMDI Resin Manufacturing 

Worker Activities 

Year of 

Measurement 

Number 

of 

Samples 

Range of 

Values 

(mg/m3) 

Techniques/Sampling 

Used 

pMDI Production 

1994 6 0.01-0.2 Not known 

1995 6 0.01-0.2 Not known 

1996 6 0.01-0.2 Not known 

Source: EU, 2005a. 

Table 7-19 estimates the ADC and LADC for MDI/ pMDI during pMDI resin 

manufacturing based on the EU Risk Assessment data. 
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Table 7-19. Estimated Average Daily Concentrations for Data Representing MDI/ pMDI 

during pMDI Manufacturing 

Industry 

Worker 

Activity 

Description 

Concentration 

Level 

Monitored 

MDI / pMDI 

Concentration 

(mg/m3) 

Average Daily 

Concentration 

(μg/m3) 

Lifetime 

Average Daily 

Concentration 

(μg/m3) 

pMDI 

Production unknown 

Maximum 0.2 46 26 

Minimum 0.01 2.3 1.3 

Dermal exposure may occur to MDI and pMDI during resin manufacturing. As a 

conservative estimate, the EPA/OPPT 2-Hand Dermal Contact with Liquid Model estimates a 

dermal exposure of 8.4 to 25 mg/kg/day for MDI/ pMDI at 100 percent concentration (see 

Section 3.2.2). 

As discussed in Section 6.1.2 for general resin manufacturing, the frequency of exposure 

is assessed to be 250 days per year and the duration of exposure is assessed to be 8 hours per 

day. 

Uncertainty in Exposure Assessment 

The quality of the monitoring data presented in the EU Risk Assessment is unclear. The 

data were obtained from 1994 to 1996 in European workplaces and may not be representative of 

conditions in the U.S. In addition, the sampling method was not discussed; therefore, it is not 

known whether these values are time weighted averages. Overall data limitations and 

uncertainties are discussed in Section 5.0. 

Environmental Releases of MDI from pMDI Manufacturing 

Table 7-20 presents diisocyanates releases during Plastics Material and Resin 

Manufacturing (NAICS code 325211) reported to the TRI for reporting year 2008. 
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Table 7-20. Releases of Diisocyanates During Plastics Material and Resin Manufacturing Reported in TRI for R

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) 

Off-Site Transfers for Release 

(lb) 

Stack 

Air 

Fugitive 

Air 

Total 

Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

325211 (68 sites) 

Plastics Material and Resin Manufacturing 858 2,936 3,793 0 25 3,818 44,551 58,338 102,889 

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 and releaseDecember 2009. These data only include quantities that are released or transferred off-site for treatment in wastewater & incineration units. It dosent to on- and off-site waste management such as recycling and reuse. a - Table is based on TRI release data for the diisocyanates category (N120), which includes MDI and 19 other diisocyantes. b - Off-Site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs)
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7.5.2 PB and MDF Manufacture 

In their proposed Airborne Toxic Control Measure, CARB indicated that pMDI can be 

used in MDF or PB (CARB, 2007a). It can be added during the blending of wood chips prior to 

pressing operations (EU, 2005a). As stated previously, pMDI is not believed to be widely used in 

HWPW production. 

Process Description 

The MDF and PB production processes using pMDI are expected to be similar to the 

general production processes described in Section 6.2.1, except that pMDI resins are expected to 

be introduced during the blender operation. Information on the specific PPE and engineering 

controls used during the use of pMDI resins in CWP manufacture was not available. 

Exposure Assessment from MDI in PB and MDF Manufacturing 

The EU Risk Assessment provided some data provided by industry for the use of MDI in 

PB and MDF manufacturing, as shown in Table 7-21. 

Table 7-21. Inhalation Monitoring Data from EU Risk Assessment for MDI/ pMDI 

Concentrations during PB Manufacturing 

Application 

Worker 

Activity 

Description 

Number of 

Samples 

Monitored MDI / 

pMDI Concentration 

(mg/m3) 

Monitoring 

Type Year 

PB (chipboard) Blending 1 <0.015 Personal + Static 

(Area) 1998 

Source: EU, 2005a. 

Note: The monitoring method used measures total isocyantates and does not distinguish between pMDI and pure 

MDI. 

Table 7-22 estimates the ADC and LADC for MDI/ pMDI during PB and MDF 

manufacturing based on the EU Risk Assessment data for PB manufacturing assuming that MDF 

workplace concentrations will be similar to PB workplace concentrations. 

Table 7-22. Estimated Average Daily Concentrations for Data Representing MDI/ pMDI 

during PB and MDF Manufacturing 

Industry 

Worker Activity 

Description 

Monitored MDI / 

pMDI 

Concentration 

(mg/m3) 

Average Daily 

Concentration 

(μg/m3) 

Lifetime Average 

Daily 

Concentration 

(μg/m3) 

PB or MDF blending <0.015 3.4 2.0 

Dermal exposure may occur to MDI and pMDI during CWP manufacturing. As a 

conservative estimate, the EPA/OPPT 2-Hand Dermal Contact with Liquid Model estimates a 

dermal exposure of 8.4 to 25 mg/kg/day for pMDI at 100 percent concentration (see Section 

3.2.2). 
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As discussed in Section 6.2.2 for general CWP manufacturing, the frequency of exposure 

is assessed to be 250 days per year and the duration of exposure is assessed to be 8 hours per 

day. 

Uncertainty in Exposure Assessment 

Only one potentially relevant data point for MDI/ pMDI was available in the EU Risk 

Assessment for PB and MDF, but it is unclear whether the data is representative of conditions in 

the U.S. Overall data limitations and uncertainties are discussed in Section 5.0. 

Environmental Releases of MDI from PB and MDF Manufacturing 

Table 7-23 presents releases of diisocyanates, including MDI, during Reconstituted 

Wood Product Manufacturing (NAICS code 321219) reported to the TRI for reporting year 

2008. 
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Table 7-23. Releases of Diisocyanates during Reconstituted Wood Product Manufacturing Reported in 

Year 2008a

Primary 

NAICS 

Code 

NAICS 

Description 

On-Site Releases (lb) 

Off-Site Transfers for 

Release (lb) 

T

Re

(

Stack 

Air 

Fugitive 

Air 

Total 

Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

321219 

(30 sites) 

Reconstituted Wood Product Manufacturing 7,789 1,236 9,025 0 0 9,025 0 0 0 

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 an

December 2009. These data only include quantities that are released or transferred off site for treatment in wastewater and incineration quantities sent to on- and off-site waste management such as recycling and reuse. a - Table is based on TRI release data for the diisocyanates category (N120), which includes MDI and 19 other diisocyanates. b - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). 
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7.5.3 Downstream Product Manufacture and Commercial/ Consumer Use 

MDI/ pMDI exposures and releases are expected to be negligible or non-quantifiable 

during downstream product manufacture and commercial use because MDI/ pMDI is consumed 

during the CWP manufacture process (USEPA, 2011c). Consumer exposure is expected to be 

negligible as well, for the same reasons as given above. 

 Table 7-24 presents releases of diisocyanates, including MDI, for several downstream 

product manufacturing industries reported to the TRI for reporting year 2008. Of the industries 

that reported diisocyanates releases, these releases were to fugitive air or transferred off site for 

disposal. Many industries did not report any releases, although this may be due to the reporting 

threshold not being met. Additionally, MDI is also used as a component in wood glues for 

downstream uses of CWP products such as furniture assembly and building construction. The 

use of these glues may be the source of releases (EU, 2005a). 
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Table 7-24. Releases of Diisocyanates in Various Downstream Product Manufacturing Industries Rep

Reporting Year 2008a

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) 

Off-Site Transfers for 

Release (lb) 

Tota

Relea

(lb) 

Stack 

Air 

Fugitive 

Air 

Total 

Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

321911 

(8 sites) 

Wood Window and Door Manufacturing 0 5 5 0 0 5 0 0 0 

321918 

(1 site) 

Other Millwork (including Flooring) 0 0 0 0 0 0 0 0 0 

321991 

(63 sites) 

Manufactured Home (Mobile Home) Manufacturing 0 0 0 0 0 0 0 57 57 

321992 

(2 sites) 

Prefabricated Wood Building Manufacturing 0 0 0 0 0 0 0 0 0 

337211 

(4 sites) 

Wood Office Furniture Manufacturing 0 0 0 0 0 0 0 0 0 

337212 

(1 site) 

Custom Architectural Woodwork and Millwork Manufacturing 0 23 23 0 0 23 0 0 0 

337122 

(1 site) 

Nonupholstered Wood Household Furniture Manufacturing 0 0 0 0 0 0 0 0 0 

337127 

(2 sites) 

Institutional Furniture Manufacturing 0 13 13 0 0 13 0 0 0 

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 an

December 2009. These data only include quantities that are released or transferred off site for treatment in wastewater and incineration quantities sent to on- and off-site waste management such as recycling and reuse. a - Table is based on TRI release data for the diisocyanates category (N120), which includes MDI and 19 other diisocyanates. b - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). 
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7.6 Vinyl Acetate Monomer (VAM) and Polyvinyl Acetate (PVA)

Vinyl acetate monomer (VAM) (CASRN 108-05-4) is used almost exclusively as an 

intermediate for manufacturing polyvinyl acetate (PVA) (CASRN 9003-20-7) (SCHER, 2008a). 

These PVA polymers are used as ingredients in a variety of products, which include CWP 

adhesives. Vinyl acetate exists as a colorless, flammable liquid (Kirk-Othmer, 2005b). Table 

7-25 presents the occupational exposure limits for VAM. There are no OELs established for 

PVA. 

Table 7-25. Occupational Exposure Limits for Vinyl Acetate Monomer (CASRN 108-05-4) 

Source Limit Type Exposure Limits 

OSHA PEL None currently listed None currently listed 

NIOSH REL 15-Minute ceiling 4 ppm, 15 mg/m3

ACGIH TLV TWA 10 ppm, 35 mg/m3

STEL 15 ppm, 53 mg/m3

Source: OSHA, 2006; NIOSH, 2005; ACGIH, 2009. 

This section provides the complete exposure assessment for VAM during the following 

life cycle stages: PVA manufacturing, CWP manufacturing, downstream product manufacturing, 

and commercial/ consumer use. 

7.6.1 Manufacture of PVA resin 

PVA adhesives are primarily used for packaging and wood gluing. PVA adhesives are 

stable and can accept many types of modifying additives without being damaged. In addition, the 

adhesives can be adapted to any type of machine operation, such as spray guns, rollers, extrudertype devices, etc. (Kirk-Othmer, 2005b). PVA resin manufacturing is classified under NAICS 

code 325211 – Plastics Material and Resin Manufacturing. 

Process Description 

PVA is principally manufactured through the polymerization of VAM by bulk, solution, 

suspension, and emulsion processes. However, 90 percent of PVA or VAM copolymers are made 

by emulsion techniques. Various finishing techniques are used to reduce the residual monomer in 

the emulsion polymer, such as raising the temperature, adding a more concentrated initiator, or 

using mechanical means such as stripping. Typical industrial polymerizations are carried out to 

over 99 percent conversion; therefore, there is no need to reduce the unreacted monomer unless 

very low levels are required to meet regulatory, product, or workplace requirements. Most PVA 

emulsions contain less than 0.5 weight percent unreacted vinyl acetate, which minimizes 

development of acetic acid and acetaldehyde byproducts by monomer hydrolysis during a long 

storage (Kirk-Othmer, 2005b). 

Typically, in PVA production processes, only a portion of the monomer and the catalyst 

is charged to the reactor, with the remainder slowly added over the course of the reaction. This 

allows for better control of the polymerization rate, which is particularly important in large-scale 

operations where heat-transfer capacity may be limited (Kirk-Othmer, 2005b). 
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The EU Risk Assessment for VAM indicates that workers normally use gloves and 

eyeglasses. During cleaning activities, workers also use respiratory protection (EU, 2008a). The 

Vinyl Acetate Council (VAC) states that for routine operations where vapor exposure is below 

established exposure limits, PPE will typically consist of the following (VAC, 2010a): 

 Flame retardant clothing, splash goggles, hard hat and safety shoes; and 

 Gloves are also recommended for handling hoses or drums. 

For routine operations with potential for minor liquid exposure (from splashes, drips or 

minor spills) and where vapor exposure is below established exposure limits, PPE typically 

would consist of (VAC, 2010a): 

 Impervious gloves, clothing, boots and a face shield; and 

 Protective clothing made of chemical- and fire-resistant materials in process areas. When 

both are needed, the chemical resistant clothing should be worn over flame retardant 

clothing. 

Respiratory Protection 

High-level exposures to VAM may occur during emergency situations; equipment 

cleaning and repairs; decontamination of areas after a spill; or during failure of piping or 

equipment containing VAM (VAC, 2010a). For these situations, VAC recommends that workers 

use full protective suits and full-face self-contained or supplied-air respiratory protection. 

Skin Protection 

Materials suitable for preventing exposures to VAM are shown in the following table. 
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Table 7-26. VAM Permeation Times for Various PPE Materialsa

Material Common Use Resultsb

Barricade Suits > 8 hours 

Teflon Suits > 8 hours 

Responder Suits > 4 hours 

North Butyl B161 (16 mil or equivalent) Gloves 5 hours 

North Butyl B324R (32 mil or equivalent) Gloves > 8 hours 

Ansell Edmont Laminate (2.5 mil or equivalent) Gloves > 6 hours 

North Silver Shield/4H (2.7 mil or equivalent) Gloves > 8 hours 

Source: VAC, 2010a 

a - Testing conducted according to the American Society for Testing and Materials (ASTM), Standard Test Method 

for Resistance of Protective Clothing Materials to Permeation by Liquids or Gases Under Conditions of Continuous 

Contact. ASTM F 739-99a. Annual Book of ASTM Standards, Vol. 11.03. 

b - Results are given as resistance time to breakthrough after continuous contact. 

Eye Protection 

Full eye and face protection is preferred and should include face shields (full length, 8 in. 

(20 cm) minimum) with forehead protection in addition to chemical splash goggles. Eye 

protection can be provided through the use of a full face masks and appropriate respiratory 

protection if vapor or mist exposure is expected (VAC, 2010a). 

Exposure Assessment for VAM in PVA Manufacturing 

 Inhalation monitoring data were not found for VAM in PVA resin manufacturing. 

Table 7-27 provides surrogate workplace monitoring data compiled in the EU Risk Assessment 

for VAM during various worker activities in the adhesives production industry. The EU Risk 

Assessment notes that the majority of the monitoring data provided are not shift averages, and 

the period of exposure is not provided for several of the data ranges. 
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Table 7-27. Surrogate Inhalation Monitoring Data from Data Representing VAM 

Concentrations during PVA Resin Manufacturing a

Adhesives Production Industry 

Year of 

Measurements 

Number of 

Samples 

Range of 

Measurement Data 

(mg/m3) 

Non 8-hr Time Weighted Averages

Formulation 1997-2000 60 0.07-32 

1995-2000 100 10.3-14.6 

1996, 2000 2 1.8-3.9 

1998, 1999 N/A 3.2-46 

Pumping monomer into tanks 1998, 1999 N/A 39-46.8 

(over 30 min) 

Pre-emulsion preparation 1998, 1999 N/A < 3.6 

(over 30 min) 

Pumping pre-emulsion into reactor 1998, 1999 N/A 18 

(over 60 min) 

8-hr Time Weighted Averages 

Filling, cleaning, opening of vessels 1996-2002 23 3.1 (50th percentile) 

14.6 (90th percentile) 

Source: EU, 2008a. 

N/A – Not Available 

a –Monitoring data is likely not a shift average. 

Table 7-28 calculates inhalation exposure to VAM during PVA manufacturing based on 

monitoring data from the EU Risk Assessment for VAM. The general facility estimate in Section 

6.1.2 for general resin manufacturing is 45 workers per site. As also discussed in Section 6.1.2, 

the frequency of exposure is assessed to be 250 days per year and the duration of exposure is 

assessed to be 8 hours per day. 
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Table 7-28. Estimated Average Daily Concentrations for Data Representing VAM during 

PVA Production using Surrogate Data from the EU Risk Assessment 

Industry 

Worker Activity 

Description 

Concentration 

Level 

Monitored VAM 

Concentration 

(mg/m3) 

Average Daily 

Concentration 

(μg/m3) 

Lifetime 

Average Daily 

Concentration 

(μg/m3) 

Adhesives 

Production 

Formulation 

Maximum 46a

 11,000 6,000 

Minimum 0.07a 16 9.1 

Pumping 

monomer into 

tanks 

Maximum 2.9b

 660 380 

Minimum 2.4b 550 310 

Pre-emulsion 

preparation 1 Data Point <0.2b

 46 26 

Pumping preemulsion into 

reactor 

1 Data Point 2.3b

 530 300 

Filling, cleaning, 

opening of vessels 

90th percentile 14.6 3,300 1,900 

50th percentile 3.1 710 400 

a –Based on monitoring data that is likely not a shift average (EU, 2008a); therefore, average daily exposures may 

be overestimated. 

b- These exposures were calculated by converting the monitoring data over the period of exposure to an 8-hour 

average. For example, a measurement of 46.8 mg/m3 over 30 minutes was converted to 2.9 mg/m3 over 8 hours. 

The dermal model used for estimates in this report could not be adjusted to account for 

the higher volatility of VAM - see Section 3.2.2 for an explanation. 

Uncertainty in Exposure Assessment 

As noted above, most of the monitoring data provided in Table 7-27 are not shift 

averages and the period of exposure was not provided. Therefore, some exposure calculations 

may be overestimated. Additionally, the data provided in the EU Risk Assessment may not be 

representative of current conditions in the U.S. Overall data limitations and uncertainties are 

discussed in Section 5.0. 

Environmental Releases of VAM from PVA Resin Manufacturing 

Table 7-29 presents releases of VAM from Plastics Material and Resin Manufacturing 

(NAICS Code 325211) as reported to the TRI for reporting year 2008. The majority of VAM is 

disposed of by off-site incineration (>5 million pounds). On-site releases are primarily divided 

between stack air and fugitive air.
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Table 7-29. Releases of VAM during Plastics Material and Resin Manufacturing Reported in TRI for Re

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) Off-Site Transfers for Release (lb) 

Stack 

Air 

Fugitive 

Air Total Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

325211 

(43 sites) 

Plastics Material and Resin Manufacturing 297,366 355,341 652,707 18 54 652,779 2,655 0 2,655 

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 an

December 2009. These data only include quantities that are released or transferred off site for treatment in wastewater and incineration quantities sent to on- and off-site waste management such as recycling and reuse. a - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). 
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7.6.2 HWPW Manufacturing 

CARB indicated in their rulemaking that PVA is typically used in HWPW production 

(CARB, 2007a). Section 7.6.1 indicated that typical industrial polymerizations, such as the 

polymerization of VAM to PVA, are carried out to over 99 percent conversion. Similarly, 

according to the EU Risk Assessment, there is normally no direct use of VAM in CWP facilities. 

The VAM is converted to PVA, which contains small amounts of residual VAM (ranging from 

less than 2 ppm to 3000 ppm) (EU, 2008a). 

Process Description 

The general processes for HWPW manufacturing and downstream product manufacturing 

are expected to follow the general processes described in Sections 6.2.1 and 6.3.1. No specific 

information on engineering controls and PPE were found. 

Exposure Assessment for VAM during HWPW Manufacturing 

Inhalation exposure information on the manufacture and use of composite wood products 

containing VAM was not found. VAM is typically polymerized into PVA resin at over 99 

percent conversion. Additionally, the process of applying PVA to the wood veneers is not 

expected to generate mists; therefore, inhalation exposures to residual VAM are expected to be 

negligible. 

The dermal model used for estimates in this report could not be adjusted to account for 

the higher volatility of VAM - see Section 3.2.2 for an explanation. 

As discussed in Section 6.2.2 for composite wood product manufacturing, the frequency 

of exposure is assessed to be 250 days per year and the duration of exposure is assessed to be 8 

hours per day. 

Uncertainty in Exposure Assessment 

 Overall data limitations and uncertainties are discussed in Section 5.0. 

Environmental Releases of VAM during HWPW Manufacturing and Downstream 

Product Manufacturing. 

 No release data for VAM were found in CWP manufacturing and downstream product 

manufacturing. 

 

7.6.3 Downstream Product Manufacture and Commercial/ Consumer Use 

The processes for downstream product manufacturing and commercial use are expected to be 

identical to the processes described in Section 6.3.1 and 6.4. No workplace monitoring data were 

found for VAM in downstream product manufacturing or commercial use. VAM will be 

polymerized in the cured PVA; therefore, inhalation exposures to residual VAM are expected to 

be negligible, and dermal exposures cannot be quantified during these life cycle stages. Since 
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consumer use would be in this set of life cycle stages, consumer exposure is expected to be 

negligible as well.
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7.7 Chromium (III) 

Certain chromium (III) metal salts have been added to PVA resin formulations to create 

water-resistant bonds, which have application in CWP manufacture (Brabetz et al., 1978a). The 

exposure assessment encompasses the following life cycle stages: addition of Cr(III) salts to 

PVA resin; CWP manufacture; downstream product manufacture; and commercial/ consumer 

use. Table 7-30 presents exposure limits for chromium (III) compounds. 

Table 7-30. Occupational Exposure Limits for Chromium (III) (CASRN 16065-83-1) 

Source Chemical Limit Type Exposure Limit

OSHA PEL Chromium (II) and chromium 

(III) compounds 8-hour TWA 0.5 mg Cr/m3

NIOSH REL

Chromium metal and 

chromium (II) and chromium 

(III) compounds 

8-hour TWA 0.5 mg Cr/m3

ACGIH TLV Metal and Cr(III) compounds, 

as Cra 8-hour TWA 0.5 mg/m3

Source: OSHA, 2006; NIOSH, 2005; ACGIH, 2009. 

a - Appendix A4 - Not Classifiable as a Human Carcinogen.

Process Description 

Literature describes adding an acid hardener, such as a chromium (III) nitrate solution, to 

PVA resin formulations in concentrations from 0.5 to 10 percent (Brabetz et al., 1978a). No 

specific information concerning engineering controls and PPE was found in the literature. 

Exposure Assessment for Chromium (III) 

No inhalation exposure data were found for chromium (III) in PVA resin manufacturing 

or other downstream life cycle stages. Inhalation exposures are expected to be negligible because 

chromium (III) nitrate is used in solution, used as a component of a liquid resin, and then 

entrained in the cured resin. 

In an example found in the literature, a saturated solution of chromium nitrate was added 

to the PVA resin (Brabetz et al., 1978a). Since saturation depends on a number of variables, 

exposure to 100 percent chromium is presented as a conservative estimate. Dermal exposures to 

100 percent chromium would be expected to be 8.4 to 25 mg/kg/day, using the EPA/OPPT 2-

Hand Dermal Contact with Liquid Model (see Section 3.2.2). During CWP manufacturing, the 

concentration of chromium in the PVA resin is less than ten percent, the resulting dermal 

exposure for chromium is up to 2.5 mg/kg/day. Dermal exposures are not quantifiable after CWP 

manufacturing because the chromium salts crosslink with the PVA upon curing (Frihart, 2005a). 
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General facility estimates for resin manufacturing in Section 6.1.2 estimate 8 hours of 

exposure per day over 250 exposure days per year. 

Uncertainty in Exposure Assessment 

The estimate for the amount of chromium salt added to PVA resin is based on a patent 

from 1978. The actual industrial use of chromium salts in PVA resin and downstream products is 

unclear. Additionally, the specific concentration of the chromium salt solution is unknown; only 

a conservative dermal exposure estimate was possible. Overall data limitations and uncertainties 

are discussed in Section 5.0. 

 

Environmental Releases of Chromium and Chromium Compounds 

 As reported to the TRI for reporting year 2008, Table 7-31 presents releases during PVA 

resin manufacturing and Table 7-32 presents releases from downstream product manufacturing. 

Releases during downstream product manufacturing may be due to non-CWP sources, such as 

welding or metal components in the downstream products. Note that the TRI data are not limited 

to chromium (III) compounds.
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Table 7-31. Release of Chromium and Chromium Compounds during Plastics Material and Resin Manufact

for Reporting Year 2008 

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) Off-Site Transfers for Release (lb) 

Stack 

Air 

Fugitive 

Air Total Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

CHROMIUM 

325211 (3 sites) 

Plastics Material and Resin Manufacturing 9 250 259 0 70 329 14 186 200 

CHROMIUM COMPOUNDSb

325211 (10 sites) 

Plastics Material and Resin Manufacturing 605 392 997 13,000 407,379 421,376 77,901 322 78,223 

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 and re

December 2009. These data only include quantities that are released or transferred off site for treatment in wastewater and incineration unitssent to on- and off-site waste management such as recycling and reuse. a - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). b - Releases for chromium compounds only include the portion of the compound that is elemental chromium.
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Table 7-32. Releases of Chromium and Chromium Compounds during Downstream Product Manufacturin

Reporting Year 2008 

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) Off-Site Transfers for Release (lb) 

Stack 

Air 

Fugitive 

Air Total Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

CHROMIUM 

337127 (4 sites) 

Institutional Furniture Manufacturing 5 255 260 0 0 260 501 0 501 

337212 (3 sites) 

Custom Architectural Woodwork and Millwork Manufacturing 0 2 2 0 0 2 182 72 254 

337215 (4 sites) 

Showcase, Partition, Shelving, and Locker Manufacturing 0 250 250 1 0 251 0 0 0 

CHROMIUM COMPOUNDSb

321911 (2 sites) 

Wood Window and Door Manufacturing 22 0 22 0 0 22 826 7,191 8,017 

337127 (1 site) 

Institutional Furniture Manufacturing 6 4 10 0 0 10 0 0 0 

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 and re

December 2009. These data only include quantities that are released or transferred off site for treatment in wastewater and incineration unitssent to on- and off-site waste management such as recycling and reuse. a - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). b - Releases for chromium compounds only include the portion of the compound that is elemental chromium.
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7.8 Ammonia

Ammonia may be used in a variety of industries, including the manufacture of synthetic 

fibers, plastics and resins. In the CWP industry, ammonia may include use as a post-treatment 

additive to reduce formaldehyde emissions (Mannsville, 2005a). Table 7-33 lists current OELs 

for ammonia. 

Table 7-33. Exposure Limits for Ammonia (CASRN 7664-41-7) 

Source Limit Type Exposure Limit 

OSHA PEL 8-hour TWA 50 ppm (35 mg/m3

) 

NIOSH REL 

TWA for up to a 10-hour workday 

during a 40-hour workweek 25 ppm (18 mg/m3

) 

STEL 35 ppm (27 mg/m3) 

ACGIH TLV 

For a normal 8-hour workday and a 

40-hour workweek. 25 ppm (18 mg/m3

) 

STEL 35 ppm (27 mg/m3) 

Source: OSHA, 2006; NIOSH, 2005; ACGIH, 2009. 

7.8.1 Ammonia in CWP Manufacture 

Literature suggests that ammonia may be used as a scavenger to reduce the free 

formaldehyde emissions, including treatment of the CWP with ammonia gas or ammonia salts. 

Process Description 

Two post-treatment methods to reduce formaldehyde release from CWPs use ammonia 

gas: the Verkor FD-EX and the RYAB methods. 

The FD-EX method is a two-step procedure that is done in a three-chambered plant. In 

the first chamber, the CWP is treated with an excess of ammonia gas at temperatures between 30 

and 35 degrees Celsius, reducing the formaldehyde by the formation of hexamethylene 

tetramine. In the second chamber, most of the excess ammonia is desorbed. In the third chamber, 

the rest of the ammonia reacts with formic acid and other wood compounds to be fixed as 

ammonium salt in the board. As a consequence of the last reaction chamber, no ammonia odor 

should be present to lessen the suitability of the finished boards. However, the literature suggests 

that the relatively high cost of the FD-EX method has hindered its wider distribution in industry 

(Pizzi, 1989a). 

 The RYAB method treats the CWP with ammonia gas in a single step. The treatment 

takes place in a special chamber using a pressure gradient. The reaction is completed during 

storage of the treated board. The reaction is the same as in the FD-EX method. However, the 

ammonia odor can remain on the CWPs for weeks (Pizzi, 1989a). 
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 Another post-treatment is the ASSI method, which uses such ammonia salts are 

ammonium carbonate, ammonium bicarbonate or ammonium carbamate as scavenging agents. 

The ammonia is slowly liberated from the salts and acts as a scavenger. The salts can be added to 

the adhesive or sprayed as solids or solutions on the surface of the boards. (Pizzi, 1989a). 

No additional information on the use of engineering controls and PPE during ammonia 

use in CWP production or downstream uses was found. 

 

Exposure Assessment for Ammonia 

No monitoring data were found for ammonia in CWP manufacturing. However, 

therefore, inhalation exposures are expected to gaseous ammonia. Because no monitoring data 

are available, a “what-if” exposure concentrations were calculated using the OSHA PEL and are 

shown in Table 7-34. 

As discussed in Section 6.2.2 for composite wood product manufacturing, the frequency 

of exposure is assessed to be 250 days per year and the duration of exposure is assessed to be 8 

hours per day. 

Table 7-34. Estimated “What-If” Average Daily Concentrations of Ammonia Based on the 

OSHA PEL 

Source Limit Type 

Ammonia Exposure 

Limit (mg/m3) 

Average Daily 

Concentration 

(μg/m3) 

Lifetime Average 

Daily Concentration 

(μg/m3) 

OSHA PEL 8-hour TWA 35 8,000 4,600 

Based on the potential post-treatment methods described in the literature, workers will 

likely contact ammonia in gaseous form. Dermal exposures to gaseous ammonia are nonquantifiable (see Section 3.2.2). 

Uncertainty in Exposure Assessment 

There is a lack of monitoring data for ammonia during CWP manufacturing. Exposure 

estimates are based on OSHA PELs and may overestimate or underestimate current conditions, 

depending on the level of compliance in industry. Additionally, literature identifies several types 

of ammonia treatment for CWPs, involving both gaseous ammonia and ammonia salts. However, 

it is unclear whether any of these methods can be considered “typical” for the industry. 

Environmental Releases of Ammonia 

Table 7-35 presents ammonia releases during Hardwood Veneer and Plywood 

Manufacturing (NAICS 321211) and Reconstituted Wood Product Manufacturing (NAICS 

321219) as reported to the TRI for reporting year 2008. Note that TRI lists a “qualifier” for 

ammonia, stating that 100 percent anhydrous ammonia must be reported, but only 10 percent of 

aqueous ammonia is reportable. Ammonia releases from reconstituted wood product 

manufacturing are considerably higher than in HWPW manufacturing. 
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7.8.2 Downstream Product Manufacture and Commercial/ Consumer Use 

Ammonia exposures are not expected to be significant during downstream product 

manufacture and commercial use because nitrogen-based scavenger additives (e.g., ammonia) 

with low molecular weight may have the potential to diffuse from the wood matrix in the final 

product, but the physical-chemical properties of these neat chemicals would generally preclude 

much volatility. In addition, should the additives react with formaldehyde, as intended, the 

corresponding adducts will be much more likely to irreversibly bind to the wood chemical 

moieties (USEPA, 2011c). Therefore, exposures of residual ammonia are expected to be 

negligible for these life cycle stages. Additionally, no release data for ammonia were found in 

any downstream product manufacturing or commercial use industries. Since consumer use 

would be in this set of life cycle stages, consumer exposure is expected to be negligible as well.
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October, 2011 – draft deliberative – do not cite or quote Page 72 

Table 7-35. Environmental Releases of Ammonia during Hardwood Veneer and Plywood Manufacturi

321211) and Reconstituted Wood Product Manufacturing (NAICS Code 321219) Reported in TRI for Re

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) Off-Site Transfers for Release (lb) 

Stack 

Air 

Fugitive 

Air 

Total 

Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

321211 

(1 site) 

Hardwood Veneer and Plywood Manufacturing 0 5 5 0 0 5 0 0 0 

321219 

(7 sites) 

Reconstituted Wood Product Manufacturing 272,885 1,285 274,170 1,295 751 276,216 314 0 314 

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 an

December 2009. These data only include quantities that are released or transferred off site for treatment in wastewater and incineration quantities sent to on- and off-site waste management such as recycling and reuse. a - TRI lists a “qualifier” for ammonia, indicating that 100 percent of anhydrous ammonia must be reported, but only 10 percent of aqureportable. b - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs).
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7.9 Phenol

Phenol (CASRN 108-95-2) is primarily used as an intermediate in the manufacture of 

bisphenol-A and in the synthesis of phenolic resins. Phenol exists as a crystalline solid at room 

temperature but is normally sold as a heated liquid in bulk quantities (Mannsville, 2008a; KirkOthmer, 2005c). Table 7-36 lists established OELs in the U.S. 

Table 7-36. Occupational Exposure Limits for Phenol (CASRN 108-95-2) 

Source Limit Type Exposure Limit 

OSHA PELa 8-hour TWA 5 ppm (19 mg/m3

) 

NIOSH RELa

TWA for up to a 10-hour workday 

during a 40-hour workweek 5 ppm (19 mg/m3

) 

STEL 15.6 ppm (60 mg/m3) 

ACGIH TLVa TWA for a normal 8-hour workday 

and a 40-hour workweek. 5 ppm (19 mg/m3

) 

Source: OSHA, 2006; NIOSH, 2005; ACGIH, 2009. 

a – OSHA, NIOSH and ACGIH also assign a "Skin" notation to phenol. 

7.9.1 Manufacture of Phenol-Formaldehyde Resin 

Phenolic resins were initially used mainly for exterior applications, while UF resins were 

used for interior applications. However, the concern over formaldehyde emissions has caused 

some replacement of UF by phenol–formaldehyde adhesives. Phenolic resins typically comprise 

5–25% by weight of plywood, particleboard, waferboard, and fiberboard. (Kirk-Othmer, 2003a). 

Process Description 

Batch processes for most phenolic resins (novolaks, resols) employ the equipment shown 

in Figure 7-2. Reactants are added into the stirred reaction vessel through weigh tanks. Reactions 

are typically carried out under vacuum or an inert gas (Kirk-Othmer, 2003a). Typically, resols 

remain liquid and are drummed at temperatures less than 25°C. Resols contain free (unreacted) 

phenol up to 15% (EU, 2006a). 
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Figure 7-2. Typical Phenolic Resin Production Unit (Kirk-Othmer, 2003a) 

Exposure Assessment for Phenol in Manufacture of PF Resin 

Inhalation exposure to phenol during PF resin manufacturing is expected during filling, 

transfer, sampling, drumming as well as during cleaning, maintenance and repair work. The final 

PF resins with free phenol content up to 15% are an additional source of exposure, particularly 

when they cool down from elevated temperature outside the closed systems (EU, 2006a). 

The EU Risk Assessment provided limited monitoring data for phenol exposures during 

phenolic resin manufacturing, which are provided in Table 7-37. The OSHA IMIS database 

contained two data points from 1980 and 1985 for potential exposures to phenol during Plastics 

Material and Resin Manufacturing (NAICS code 325211). However, both of these data points 

reported values of “NF,” or not found; therefore, only the EU Risk Assessment data were 

included in this report. All monitoring data presented are below or equal to the established 

exposure limit of 5 ppm (19 mg/m3

) established by OSHA, NIOSH, and ACGIH (shown in 

Table 7-36). 
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Table 7-37. Inhalation Monitoring Data from 2006 EU Risk Assessment for Phenol during 

Phenolic Resin Manufacturing 

Type of 

Sampling 

Work 

Area/Activities Year 

Number of 

Measurements 

Range of 

Measured 

Values 

(mg/m3)

a

Mean 

(mg/m3) 

90th

Percentile 

(mg/m3) 

Duration 

and 

Frequency 

Unknown Phenolic Resin 

Manufacturing 1997 10 0 – 1.2 0.1 0.4 unknown 

Source: EU, 2006a 

a – Limit of detection is unknown. 

Table 7-38 presents the estimated ADC and LADC for phenol during phenolic resin 

manufacturing based on monitoring data from the EU Risk Assessment. 

Table 7-38. Estimated Average Daily Concentrations for Data Representing Phenol during 

Phenolic Resin Manufacturing 

Industry 

Worker Activity 

Description 

Concentration 

Level 

Monitored 

Phenol 

Concentration 

(mg/m3) 

Average Daily 

Concentration 

(μg/m3) 

Lifetime 

Average Daily 

Concentration 

(μg/m3) 

Phenolic Resin 

Manufacturing Unknown 

Maximum 1.2 270 160 

Mean 0.1 23 13 

Minimum < 0.041a < 9.4 < 5.3 

a – The EU Risk Assessment reported a concentration of zero, as shown in Table 7-37. The limit of detection is 

unknown; therefore EPA assesses a minimum concentration of 0.041 mg/m3

 based on the limit of detection 

specified for phenol in OSHA Analytical Method No. 32. 

For the large scale production of resins, the EU Risk Assessment assumes that automated 

processes are employed. In an automated large-scale process, worker activities are limited to 

loading the bags on conveyer belts. The further steps, opening and emptying the bags, are 

performed automatically. In addition to large scale production, smaller amounts of specialty 

resins are produced. In a small-scale specialty process, phenol is manually dumped into reaction 

vessels. PF resins containing ≥ 3% unreacted phenol are considered corrosive; therefore, workers 

typically avoid daily dermal exposure and skin contact is limited to occasional events (EU, 

2006a). 

The EU performed a quantitative assessment of dermal exposures using the EASE model. 

Exposure was assessed to be between 2.1 and 21 mg/worker/day for the handling of corrosive 

phenol and corrosive resins (≥ 3% phenol) (EU, 2006a). The EPA/OPPT 2-Hand Dermal Contact 

with Liquid Model is assessed as conservative, which estimates a dermal exposure of 1.3 to 3.8 

mg/kg/day (see Section 3.2.2) for a concentration of 15%, (EU, 2006a) although actual 

exposures may be less due to the corrosive nature of phenol. 

As discussed in Section 6.1.2 for general resin manufacturing, the frequency of exposure 

is assessed as 250 days per year and the duration of exposure is assessed as 8 hours per day. 
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Uncertainty in Exposure Assessment 

The quality of the monitoring data presented in the EU Risk Assessment is uncertain. 

There were limited data available from 1997 and the data may not be representative of current 

conditions in the U.S. Additionally, due to the health effects of phenol, exposures are expected to 

be mitigated with PPE. Actual exposures to phenol are uncertain. Overall data limitations and 

uncertainties are discussed in Section 5.0. 

Environmental Releases of Phenol during the Manufacture of PF Resin 

Table 7-39 presents releases of phenol during NAICS Code 325211 (Plastics Material 

and Resin Manufacturing), as reported to the TRI for reporting year 2008. The large majority of 

releases are incinerated off site (2.5 million pounds). 
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Table 7-39. Environmental Releases of Phenol during Plastics Material and Resin Manufacturing Rep

Reporting Year 2008 

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) 

Off-Site Transfers for 

Release (lb) 

T

Rel

(

Stack 

Air 

Fugitive 

Air 

Total 

Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

325211 

(52 sites)

Plastics Material and Resin Mfg 139,001 137,432 276,433 2,149 286 278,868 826,294 167,525 993,819 1,2

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 an

December 2009. These data only include quantities that are released to the environment or transferred off site for treatment in wastewat

It does not include quantities sent to on- and off-site waste management such as recycling and reuse. a - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). 
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7.9.2 Phenolic Resins in CWP Manufacturing 

Seventy five percent of phenolic resins were then used in oriented strand board (OSB) 

manufacture and 25 percent were for other uses such as plywood manufacture (Mannsville 

2008b). Different phenolic resins are used for different types of wood; for example, plywood and 

PB adhesives contain liquid resol resins. Other types of wood products such as waferboard and 

OSB are bonded with solid resins (Kirk-Othmer, 2003a). 

Process Description 

The general processes for CWP manufacturing is expected to follow the general 

processes described in Section 6.2.1. 

Exposure Assessment for Phenolic Resins in CWP Manufacturing 

As stated previously, phenolic resins (resols) may contain <1% to 15% free phenol. The 

EU Risk Assessment indicated that during the hardening process, some free phenol is chemically 

bound and some is released. Occupational exposure to vapors is assumed during mixing of 

phenol-containing preparations and processing of resins at elevated temperatures. Dermal 

exposures are also possible through direct handling of phenolic resins (EU, 2006a). 

Limited monitoring data was provided in the EU Risk Assessment provided for phenol 

exposures during the use of phenolic resins. Measurements taken from 1990 to 1995 were 

provided for the use of phenolic resins in the plastics processing and woodworking industries, as 

shown in Table 7-40. The OSHA IMIS database did not provide any data for the use of phenol in 

CWP manufacturing. All monitoring data presented are below or equal to the established 

exposure limit of 5 ppm (19 mg/m3

) established by OSHA, NIOSH, and ACGIH (shown in 

Table 7-36). 

Table 7-40. Inhalation Monitoring Data from 2006 EU Risk Assessment for Phenol during 

Phenolic Resin Processing 

Type of 

Sampling Activities Year 

Number of 

Samples 

(number of 

premises) 

Specific 

Conditions 

50th

Percentile 

(mg/m3) 

90th

Percentile 

(mg/m3) 

95th

Percentile 

(mg/m3) 

8-hr TWA 

Processing of 

phenolic resins 

in the plastics 

processing and 

woodworking 

industries 

1990-

1995 

329 (136) Total <1.0 a

 1.0 1.3 

196 (91) 

No local 

exhaust 

ventilation 

<1.0 a 1.0 2.0 

128 (56) 

Local 

exhaust 

ventilation 

<1.0 a 1.0 1.0 

Source: EU, 2006a 

a – These measurements were below the detection limit of 1 mg/m3

. 

Table 7-41 presents the estimated ADC and LADC for phenol during the use of phenolic 

resins based on monitoring data from the EU Risk Assessment. 
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Table 7-41. Estimated Average Daily Concentrations for Data Representing Phenol during 

CWP Manufacturing 

Industry 

Specific 

Conditions 

Concentration 

Level 

Monitored 

Phenol 

Concentration 

(mg/m3) 

Average Daily 

Concentration 

(μg/m3) 

Lifetime 

Average Daily 

Concentration 

(μg/m3) 

Processing of 

phenolic resins 

in the plastics 

processing and 

woodworking 

industries a

Total 

95th Percentile 1.3 300 170 

90th Percentile 1.0 230 130 

50th Percentile <1.0b <230 <130 

No local 

exhaust 

ventilation 

95th Percentile 2.0 460 260 

90th Percentile 1.0 230 130 

50th Percentile <1.0b <230 <130 

Local exhaust 

ventilation 

95th Percentile 1.0 230 130 

90th Percentile 1.0 230 130 

50th Percentile <1.0b <230 <130 

a – Specific worker activities are unknown. 

b – These measurements were below the detection limit of 1 mg/m3

. 

The EU Risk Assessment indicated that dermal contact with resins classified as corrosive 

(≥ 3% phenol) is limited and skin contact to non-corrosive resins (<3% phenol) may occur daily. 

Exposure measurements from a 1999 study during plywood production indicated potential 

dermal between 0.31 and 2.663 mg/hr for the whole body and between 0.012 and 0.127 mg/hr 

for the hands. The shift average was estimated to be 22 mg/day. The EU Risk Assessment also 

included an assessment of dermal exposures using the EASE model. Dermal exposure was 

assessed to be between 1.3 and 13 mg/worker/day for non-corrosive resins and between 0.3 and 

3 mg/worker/day for corrosive resins (EU, 2006a). The EPA/OPPT 2-Hand Dermal Contact with 

Liquid Model is assessed as conservative, which estimates a dermal exposure of 1.3 to 3.8 

mg/kg/day (see Section 3.2.2) for a concentration of 15% phenol. 

As discussed in Section 6.1.2 for general resin manufacturing, the frequency of exposure 

is assessed as 250 days per year and the duration of exposure is assessed as 8 hours per day. 

Uncertainty in Exposure Assessment 

The quality of the monitoring data presented in the EU Risk Assessment is unclear. There 

were limited data available from 1990 to 1995 and the data may not be representative of current 

conditions in the U.S. The data are a general set of data for phenolic resins in the plastics and 

woodworking industries and may not all be applicable to the specific CWPs of interest. 

Additionally, due to the health effects of phenol, exposures are expected to be mitigated with 

PPE. Actual exposures to phenol are uncertain. Overall data limitations and uncertainties are 

discussed in Section 5.0. 
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Environmental Releases of Phenol during CWP Manufacturing 

Table 7-39 presents releases of phenol during Reconstituted Wood Product 

Manufacturing (NAICS Code 321219), as reported to the TRI for reporting year 2008. The large 

majority of releases are sent through stack air (300,000 pounds). 
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Table 7-42. Environmental Releases of Phenol during Reconstituted Wood Product Manufacturing Re

Reporting Year 2008 

Primary 

NAICS 

Code NAICS Description 

On-Site Releases (lb) 

Off-Site Transfers for 

Release (lb) 

T

Rel

(

Stack 

Air 

Fugitive 

Air 

Total 

Air 

Surface 

Water Land 

Total 

On-Site 

Releases Land Other 

Total 

Off-Site 

Releases 

321219 

(10 sites)

Reconstituted Wood Product Mfg 305,814 2,472 308,286 21 155 308,462 57 0 57 3

Source: USEPA, 2009a. TRI data were obtained from the 2008 Pubic Data Release (PDR), which was frozen on September 17, 2009 an

December 2009. These data only include quantities that are released to the environment or transferred off site for treatment in wastewat

It does not include quantities sent to on- and off-site waste management such as recycling and reuse. a - Off-site water transfer includes Publicly Owned Treatment Works (POTWs) and Waste Water Treatment Plants (WWTPs). 
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7.9.3 Downstream Product Manufacturing and Commercial/ Consumer Use 

Exposure information on the use of composite wood products containing phenol was not 

found. Because the initial resin-making reaction occurs with excess formaldehyde, the phenol is 

limiting regent and is consumed for purposes of exposure (USEPA, 2011c). Therefore, 

exposures are expected to be negligible or non-quantifiable for these life cycle steps. 

Additionally, no release data for phenol were found in any downstream product manufacturing or 

commercial use industries. Since consumer use would be in this set of life cycle stages, 

consumer exposure is expected to be negligible as well. 

 

 
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8.0 KEY UNCERTAINTIES AND LIMITATIONS OF EXPOSURE ESTIMATES

The daily worker exposure inhalation concentrations, ADCs and LADCs, generated in 

this report are highly uncertain and present significant limitations for their use. The air 

concentration parameters used to estimate the associated daily exposure concentrations come 

from a variety of sources, and their representativeness of actual typical air concentrations in 

workplaces in the CWP life cycle chain is not known. The daily exposure concentrations are 

most suitable for a qualitative overview of worker exposure issues and identification of data 

gaps. Some of the most significant uncertainties and limitations are summarized below. 

Worker monitoring data were generally sparse in readily-available sources used for this 

assessment, resulting in few data points on which to estimate representative ADCs and LADCs. 

Several of the European sources’ data sets were robust, but how well these data sets may 

represent exposures to substitute chemicals in the various CWP life cycle stages in the U.S. is 

uncertain, due to potential differences in exposure limits, regulations, emissions controls, etc . 

OSHA IMIS data could only be characterized on an industry-specific level, based on 

NAICS codes. For example, UF resin manufacturing is classified under NAICS code 325211 

(Plastics Material and Resin Manufacturing); however, there are several other types of resins 

manufactured under this code. It was not possible to distinguish whether available data for this 

NAICS code was for UF resin manufacturing or for one of the many other types of resin 

manufacturing. Similarly, it was not possible to distinguish the number of sites within each 

NAICS code that were associated with each formaldehyde substitute. EU Risk Assessments and 

OECD SIDS data were also available but were not able to address all of the data gaps within the 

scope of this assessment. 

Furthermore, the characterizations of the daily inhalation concentrations (e.g., average, 

95th percentile, single point value, assumed high-end) were not consistent for the each chemical. 

These uncertainties and limitations, as related to worker inhalation exposure 

concentrations in this report, indicate that direct quantitative comparison between various 

chemicals and life cycle stages is likely to be imprecise and is not recommended. 

 There is information that suggests that substitute chemicals are used in substitute resins 

or in UF resins to reduce formaldehyde emissions. However, there was no industry information 

that indicated the prevalence of the use of substitute chemicals, and there was limited specific 

information found in literature sources for this report that indicated the amount or concentration 

of chemical used in their respective processes. Prevalence of use could impact a variety of 

parameters examined in this report, including inhalation exposure concentrations and numbers of 

exposed workers and consumers. 

 Dermal exposure estimates are also uncertain. Because literature sources’ information on 

processes, worker activities, and concentrations of substitute chemicals in materials handled by 

workers were limited, the assumptions used for dermal exposure modeling are uncertain. The 

prevalence of glove use in the assessed workplaces is unknown, and where gloves are used, the 

model results are overestimates. When used, the same dermal models were applied to all 

chemicals and life cycle steps in this assessment, making their use and dermal exposure 
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Page 84 

estimates consistent and comparable to the extent that the assumptions used in employing the 

models are correct.
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9.0 REFERENCES

ACGIH, 2009. 2009 Guide to Occupational Exposure Values. American Conference of 

Governmental Industrial Hygienists. 2009. 

APA, 2008a. The Engineered Wood Association (APA). APA Economics Report E74 - Regional 

Production and Market Outlook for Structural Panels and Engineered Wood 

Products 2008-2012. April 2008. 

AWFS, 2009a. California Air Resources Board et al. Update on California’s Composite Wood 

Products Regulations. Association of Woodworking and Furnishings Suppliers 

(AWFS) Show. July 18, 2009. 

Battelle ,1996a. Thomas J Kelly - Battelle (for California Air Resources Board). Determination 

of Formaldehyde and Toluene Diisocyanate Emissions from Indoor Residential 

Sources .November 1996. 

Brabetz et al., 1978a. Adhesive aqueous dispersions of polyvinyl alcohol graft polymers with 

acidic hardeners and process of production. U.S. Patent 4,118,357, filed May 2, 

1977 and issued October 3, 1978. 

CARB, 2007a. California Air Resources Board (CARB). Proposed Airborne Toxic Control 

Measure to Reduce Formaldehyde Emissions From Composite Wood Products. 

March 2007. 

CPA, 2008a. Composite Panel Association (CPA). 2007 North American Downstream Market 

Report.2008. 

CPA, 2009a. Composite Panel Association (CPA). Meeting Summary with ERG– Discussion 

with CPA in Response to Comments Submitted to Formaldehyde ANPR Docket.

June 19, 2009. 

Dow, 2007a. Dow Chemical Company. Product Stewardship Manual for Safe Handling and 

Storage of Epichlorohydrin. May 2007. 

EU. 2005a. European Chemicals Bureau. European Union Risk Assessment Report for MDI. 

2005. pp. 17-18, 58-78. Final Report, 2005. 

http://ecb.jrc.ec.europa.eu/documents/ExistingChemicals/RISK_ASSESSMENT/REPORT/mdireport304.pdf 

EU, 2006a. European Chemicals Bureau. European Union Risk Assessment Report for Phenol. 

2006. pp. 55-72. Final Report, November 2006. 

http://ecb.jrc.ec.europa.eu/Documents/ExistingChemicals/RISK_ASSESSMENT/REPORT/phenolreport060.pdf 
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April 2010.
Appendix A 

DEFINITION OF TERMS 
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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. 

Average Daily Concentration 

(ADC) 

The exposure concentration of a chemical, averaged over 

365 days per year and 24 hours per day. 

Ceiling Limit (C) The air concentration for a substance that should not be 

exceeded during any part of the working exposure. 

Composite-Wood Products 

(CWPs) 

The manufacture of most composite-wood products 

involves a pressing operation where the wood material is 

bonded with a resin. Because the resulting product is 

“pressed,” the term “pressed-wood” has also been used to 

refer to plywood, particleboard, fiberboard, and larger 

engineered wood products. Hardwood plywood, mediumdensity fiberboard, and particleboard are termed compositewood products in this report. 

Downstream Product 

Manufacturing 

The manufacture of commercial or consumer products, 

such as cabinets, panels, and furniture, from HWPW, MDF, 

and PB. 

Exposure Contact with a substance by inhalation, dermal contact, or 

ingestion. 

Exposure Assessment The process of determining how people come into contact 

with a 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. 
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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 pressed-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. 

Hardwood Plywood (HWPW) 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 Wood- 

 Based Structural-Use Panels’ and numbered 

 PS 2–04. 

Life Cycle All stages of a product’s development, from manufacture 

and processing to distribution, use, and disposal and 

recycling. 

Lifetime Average Daily 

Concentration (LADC) 

The exposure concentration of a chemical, averaged over 

70 years, 365 days per year, and 24 hours per day, 

assuming 40 years of exposure. 
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MDI Resin A resin containing methylene diphenyl diisocyanate (MDI) 

– see polymethylene diisocyanate (pMDI). 

Medium-Density Fiberboard 

(MDF) 

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) 

MF Resin A resin containing melamine and formaldehyde monomers. 

MUF Resin A resin containing melamine, urea, and formaldehyde 

monomers. 

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. 

Particleboard (PB) 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. 

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. 
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pMDI Resin A polymeric resin comprised of methylene diphenyl 

diisocyanate (MDI) monomers. 

PVA Resin A resin comprised of vinyl acetate monomers (VAM). 

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. 

Release Quantity of chemical released to the environment, 

including disposal (e.g., to landfills and underground 

injection wells). Release types include on-site to air, water, 

and land (with multiple sub-types for each); and off site 

transfers to water and land (no estimates of off-site 

transfers that result in air releases). 

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 utilized 

when this is warranted by observed biological effects. 

It is recommended that exposures beyond the timeweighted 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; 

TLV-STEL; 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. 

UF Resins A resin comprised of urea and formaldehyde monomers. 
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Waste Management Activities Recycle, Energy Recovery, and Treatment (destruction, 

and/or removal depending upon the context). 

What-If Type Estimate An estimate based on a set of hypothetical conditions or 

under a set of conditions for which actual exposure or 

release parameter data are incomplete or nonexistent. The 

calculated exposure, dose, or release quantity is not 

intended to provide information about how likely the 

combination of exposure or release parameter values might 

be in the actual population or about how many, if any, 

persons might actually be subjected to the calculated 

exposure or release. 
Appendix B 

DATA QUALITY PREFERENCE CRITERIA SPECIFICATIONS 
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Table B-1. Data Quality Preference Criteria Specifications 

Criterion Description/Definition Specification 

Currency Is the information up to date? Does it 

reflect current conditions? 

Process Desc.: 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 2005 or after 

Consider – Most recent data before 2005. 

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 

Unbiased Is the information objective towards 

a particular product or outcome? 

All Data: 

 Objective of the information is clear. 
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Table B-1. Data Quality Preference Criteria Specifications 

Criterion Description/Definition Specification 

 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 utilized 

 Similar processes and activities are 

performed 

 Similar levels of engineering controls 

and personal protective equipment are 

used 
Appendix C 

DATA SUMMARY INFORMATION 
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Page C-1 

The key data used for this report include OSHA IMIS data, TRI data, and US Census 

Bureau data. Table C-1 presents a summary of the raw data files and the primary data fields 

included. 

Table C-1. Key Data Source Summary 

Data Source Filename Key Data 

OSHA IMIS OSHA_IMIS_Data_Jan1979_Apr2010_Formaldehyde_Substitutes.xls SIC Code 

NAICS Code 

Establishment Name 

Inspection Type 

Sample Data 

Job Description 

Number of Workers 

Exposed 

Exposure Frequency 

Category 

Substance Code 

Sample Type 

Exposure Type 

Exposure Level 

Exposure Level Units 

TRI TRI_Releases_2008_Formaldehyde_Substitutes.xls TRIFID 

Plant Name 

CAS Number 

NAICS Code 

Point Source Air 

Emissions 

Fugitive Air Emissions 

Total Air Releases 

Surface Water 

Discharges 

Total On-site Land 

Releases 

Total On-site Releases 

Total Off-site Land 

Releases 

Other Off-site Releases 

Total Releases 

Off-site Water Transfers 

Incineration 

U.S. 

Economic 

Census 

US Census Bureau 2002.xls NAICS Code 

NAICS Description 

Number of Companies 

Number of 

Establishments 

Number of Production 

Workers 

Aggregate Production 

Hours Worked