Summary of Findings 

 It is assumed that the application of Sporicidin will be done by occupational handlers (i.e. 

duct cleaning contractors) because it requires specialized expertise and equipment; therefore, 

residential handler exposures are not anticipated. The mixing/loading portion of the handler 

exposure consists only of pouring Sporicidin from its container into the tank that serves the 

application equipment and this exposure is similar to that evaluated previously for the other 

occupational handler scenarios involving phenol. The applicator portion of the handler 

exposures, however, is unlike those evaluated previously and will vary depending upon 

application method used by a particular company at a particular jobsite. If the applications are 

made using probes inserted into the ductwork, then exposures will be limited to dermal contact 

with the probe and can be mitigated with the use of protective gloves. If the applications are 

made by an operator in the duct or plenum, such as might occur during large scale commercial 

jobs, then both significant dermal and inhalation exposures could occur. In this case, more 

extensive PPE is needed which would include chemical resistant gloves, full body coveralls and 

respiratory protection. 

Post application inhalation exposures are anticipated following the application of Sporicidin 

to HVAC ductwork as the phenol evaporates from the duct surface and mixes with air flowing 

through the duct. Both residential and occupational post application exposures are anticipated. 

These exposures were assessed using the IAQX Model and a submitted chamber emissions study 

and the Antimicrobial Version of the EPA Risk Model. The results of these assessments are 

summarized in Table 1. For the residential scenario, the estimated MOEs are greater than the 

target MOE of 300, which means that the risks are not of concern, if re-entry is delayed for 16 or 

24 hours after application, depending upon which model is used. For the commercial scenario, 

the MOEs are greater than 300 if re-entry is delayed for 0 or 3 hours. 

Table 1 – Post Application Risk Summary 

Scenario Model Used Air Exchange 

Rate 

Waiting Time Before 

Re-entry 

Inhalation MOE 

(Target MOE = 300) 

IAQX None 

24 hours 

47 

300 

Residential 

Building 

Anti-Microbial Risk 

0.30 air changes 

per hour 

None 

16 hours 

5.6 

390 

Commercial IAQX None 320 

Building Anti-Microbial Risk 

1.3 air changes per 

hour None 

3 hours 

26 

500 

There are uncertainties with this risk assessment that include the extremely limited label 

instructions, lack of model validation for this specific use pattern and limitations regarding the 

submitted chamber emission study. The study limitations include the fact that the chamber was 

maintained at an elevated temperature of 38 C (i.e. 100 F) and that the first samples were not 

collected until four hours after application. Given these conditions, it is likely that a substantial 

amount of phenol was emitted before the first sample was collected. It is recommended that 

additional data be collected to quantify phenol emissions and exposures. This data should 

include chamber studies to determine the emission rate of phenol under the conditions of use and 

whole building studies to determine how these conditions affect real world phenol exposures. 

Page 2 of 9 
1.0 - Use Pattern Information 

 This assessment is for the duct cleaning use of phenol that is listed on the Sporicidin 

Disinfectant Solution Label (EPA 8383-3). This use is listed under the heading: “TO CLEAN 

AIR DUCTS” and the label instructions are limited to the following statement: “Apply to hard, 

non-porous surfaces”. The Sporicidin Application Guide (www.sporicidin.com/mold-generalapplication-guide.htm) also includes use directions for Deodorizing HVAC Systems and Air 

Duct Cleaning. The directions for Deodorizing HVAC systems are: “Vacate area and fog or 

spray Sporicidin into HVAC system intakes while the system fan is operating and allow enough 

spray time to allow Sporicidin to contact internal HVAC air duct surfaces.” The directions for 

Air Duct Cleaning are similar to those given for deodorization. 

2.0 - Summary of Toxicological Endpoints: 

On March 9, 2004, the Antimicrobials Division Toxicology Endpoint Selection Committee 

(ADTC) reviewed the available toxicology data for phenol and discussed endpoint selection for 

use as appropriate in risk assessments. The conclusions drawn at this meeting are presented in 

the ADTC report of March 20, 2004 and the endpoints selected that are relevant for occupational 

and residential exposures are summarized in Table 1. The hazard based uncertainty factors and 

target MOEs are also listed in Table 1. For dermal exposures, only the standard uncertainty 

factors of 10X for inter-species extrapolation and 10X for intra-species variation are required. 

An additional factor of 3X to is required for short/intermediate term inhalation exposures to 

account for the use of a LOAEL and an additional 10X factor is required for long term inhalation 

exposures to account for the for the lack of a chronic study. However, no chronic exposure 

scenarios are expected for this HVAC use. There are no concerns regarding special sensitivity, 

therefore a data base uncertainty factor is not required.

Table 2- Toxicological Doses for Phenol Occupational/Residential Exposure Assessment 

Exposure 

Scenario 

Dose Used in Risk 

Assessment 

Hazard Based 

Uncertainty Factors 

Study and Toxicological Effects 

DermalA

Short and intermediateterm 

 NOAEL = 

60 mg/kg/day 

Target MOE = 100B Developmental toxicity study in rats (NTP, 

1983). Based on significant reductions from the 

control in mean fetal body weight/litter at 120 

mg/kg/day. 

Inhalation

All durations 

 LOAEL = 

0.1 mg/L 

(100 mg/m3

)

E

Target MOE = 300C

(ST, IT) 

MOE = 1000 D 

(LT) 

Dalin and Kristofferson: Physiological Effects of 

a Sub-lethal Concentration of Inhaled Phenol on 

the Rat. Ann. Zool. Fennici 11: 193-199, 1974 

LOAEL of 0.1 mg/L, based on alterations in 

sliding angle from tilting plane test, and 

significant increases in liver enzymes 

Cancer data inadequate for assessment of human carcinogenic potential (USEPA, 2002) 

Page 3 of 9 
Notes for Table 2 

A A dermal absorption factor of 50% is used since an oral endpoint was selected. Dermal absorption data were available from 

the IRIS Toxicological profile for phenol. From the available data, dermal absorption percentages of 20-50% have been 

observed from in vivo and in vitro studies. The ADTC selected the 50% dermal absorption value for phenol for use in risk 

assessments as a conservative value. This value also takes into account the irritant properties of phenol which may increase 

its dermal absorption. 

B. Includes the standard uncertainty factors of 10X for inter-species extrapolation and 10X for intra-species variation. 

C. Includes the standard uncertainty factors and an additional factor of 3X to account for the use of a LOAEL. 

D. Includes the standard uncertainty factors and an additional factor of 10X to account for lack of a chronic study. 

E. 1000 liters equals 1 m3

, therefore 0.1 mg/liter *1000 liters/m3 = 100 mg/m3

3.0 - Handler Exposures 

Although the Sporicidin label does not prohibit HVAC applications by residential handlers 

(i.e. homeowners) it is assumed that these applications will only be done by occupational 

handlers (i.e. duct cleaning contractors) because they require specialized expertise and 

equipment. The mixing/loading portion of the handler exposure consists only of pouring 

Sporicidin from its container into the tank that serves the application equipment. This exposure 

is similar to that evaluated previously for the other occupational handler scenarios involving 

phenol. 

 The applicator portion of the handler exposure, however, is unlike those evaluated 

previously and will vary depending upon application method used by a particular company at a 

particular jobsite. If the applications are made using probes inserted into the ductwork, such as 

might occur during residential and smaller scale commercial jobs, then exposures will be limited 

to dermal contact with the probe and can be mitigated with the use of protective gloves. If the 

applications are made by an operator in the duct or plenum, such as might occur during large 

scale commercial jobs, then both significant dermal and inhalation exposures could occur. In 

this case, more extensive PPE is needed which would include chemical resistant gloves, full 

body coveralls and respiratory protection. The level of respiratory protection needed depends 

upon the inhalation exposures and would range from a half mask air purifying respirator if 

exposures exceed the level of concern by a factor of less than 10 to full face airline respirators if 

exposures exceed the level of concern by a factor of 1000 or greater. If the exposures are 

unknown and/or the duct treated is a confined space, then full face airline respirators with escape 

bottles would be required. 

4.0 – Post Application Exposure Assessment 

Post application inhalation exposures are anticipated following the application of Sporicidin 

to HVAC ductwork. This exposure occurs as the phenol evaporates from the duct surface and 

mixs with air flowing through the duct. Both residential and occupational post application 

exposures are anticipated because the label does not restrict the use of Sporicidin to occupational 

use sites and because the Sporicidin website indicates that Sporicidin is used in residential 

HVAC ductwork. 

Page 4 of 9 
Submitted Data:

 MRID 455569-01 is a chamber study that measured the emissions of chemicals including 

phenol from Sporicidin applied to metal plates. This study was conducted by Air Quality 

Sciences, Inc. (AQS) and followed the ASTM D 5116 guidance. Sporicidin was applied 

undiluted to the plates using a sprayer until beads formed and the average rate of application for 

the three trials was 27.6 + 9.9 grams of product per m2 which is equivalent to a coverage rate of 

1480 ft2 per gallon. Air samples were collected at 4, 8, 24, 48, 72 and 96 hours. The plate area 

was 0.094 m2

 and the chamber volume was 0.094 m3 which yields a product loading of 1 m2/m3. 

The chamber was ventilated at the rate of 1 air change per hour. The incoming air was 

maintained at a relative humidity of 50 + 5% RH and a temperature of 38 ± 2.0°C. The results 

were reported by AQS as emission factors and were back calculated to the respective air 

concentrations as shown in Table 3. 

Table 3 - Chamber Test Results for Phenol from Sporicidin Applied to Metal Plates 

Elapsed 

Exposure 

Hour 

 Phenol Emission 

FactorA (mg/m2/hr) 

Area 

TreatedB

Phenol Emission 

RateC 

(mg/hr) 

Chamber 

Ventilation RateD 

Phenol in 

AirE (mg/m3) 

4 7.289 0.685 7.289 

8 2.135 0.201 2.135 

24 0.777 0.073 0.777 

48 0.072 0.007 0.072 

72 0.050 0.005 0.050 

96 0.071 

0.094 m2

0.007 

0.094 m3

/hr 

0.071 

A. As reported in Table 6 of the AQS report and converted to mg from ug. 

B. Estimated from the product loading factor of 1 m2

/m3 given in the AQS report. 

C. Phenol Emission rate (mg/hr) = Measured Phenol Emission Factor (mg/m2

/hr) * Treated Area (m2) 

D. Based on the chamber volume of 0.094 m3

 and the ventilation rate of one air change per hour. 

E. Phenol in Air (mg/m3

) = Phenol Emission Rate (mg/hr) /Ventilation Rate (m3/hr) 

The following uncertainties/limitations of the study should be noted: 

• The first samples were not collected until four hours after application. Given that the 

chamber was maintained at an elevated temperature of 38 C (i.e. 100 degrees F), it is 

likely that a substantial amount of phenol was emitted during the first four hours before 

the first sample was collected. 

• Many details of the study methodology and analytical techniques were not reported. 

These include the sampling collection volumes and amount of analyte detected. 

• Although the report indicated that applications were made to three metal plate samples it 

is not clear if a chamber test run was conducted with each sample since only one set of 

emission factors was reported for the study. 

Page 5 of 9 
4.1 Post Application Exposure Assessment Using the IAQX Model 

Post application inhalation exposure to phenol vapor from Sporicidin fogging applications 

was assessed using the submitted chamber data with the EPA IAQX Model 21. The IAQX 

model is available at the website: http://www.epa.gov/appcdwww/iemb/iaqx.htm. Model 21 is a 

source model within IAQX and it is based on a semi-log regression (i.e. first order decay). 

Regression calculations to determine the decay rate of the phenol emission factor were done to 

derive the input parameters for the model. A summary of the regression calculations and input 

parameters is included in Table 4 and more detailed information is contained in Appendix A. 

Table 4 – Summary of Regression Calculations and Input Parameters

Data 

Considered 

Regression 

Type 

Regression 

Formula 

R2 Model 21 E0 (mg/m2

/hr) Model 21 k factor 

4 to 96 hours Semilog Y = -0.051x + 1.18 0.80 e

1.18 = 3.2 0.051 

4 to 48 hours Semilog Y = -0.097x + 1.99 0.97 e

1.99 = 7.3 0.097 

Assumptions Used

The assumptions that were used in the IAQX Model are listed below. 

• The application time simulation was set to none. 

• For the residential scenario, the treated room volume is 300 m3, the treated area is 74 m2

and the air exchange rate is 0.3 air changes per hour. These assumptions were taken from 

the Antimicrobial Version of the EPA Risk Model. 

• For the commercial scenario, the building volume is 16,055 m3, the treated area is 2415 

m

2

 and the air exchange rate is 1.3 ACH. These assumptions were taken from the 

Antimicrobial Version of the EPA Risk Model. 

• The initial emission rate E0 is 7.3 mg/m2/hr and the k value is 0.097 based on the semilog regression of the chamber test data for time 4 to 48 hours. The regression for the 

entire data set (i.e. 4 to 96 hours) was not used because it yielded a significantly lower R2

value as shown in Table 4. 

Risk Summary 

 The results of the model runs are included in Appendix A and are summarized in Table 5. 

The average air concentrations were calculated using an averaging time of 24 hours for the 

residential scenario and 9 hours for the commercial scenario. The MOEs were calculated using 

the LOAEL of 0.1 mg/liter (i.e. 100 mg/m3) from the inhalation toxicity study. The target MOE 

is 300 and includes the standard safety factors of 10 for interspecies extrapolation, 10 for 

interspecies variation and 3 for the use of a LOAEL. For the residential scenario, the MOE is 47 

if the exposure begins immediately after application and is of concern because it is less than the 

target MOE of 300. If the exposure does not begin until 24 hours after application; however, the 

MOE is above 300 which is not of concern. For the residential scenario, the MOE is 320 if the 

exposure begins immediately after application and is not of concern because it is above the target 

MOE of 300. 

Page 6 of 9 
Table 5 – Post Application Risk Summary Based on Chamber Data and the IAQX Model 

Scenario Air 

Exchange 

Rate 

Spray 

Coverage 

(ft2/ga) 

Averaging 

Time 

Waiting Time 

Before Re-entry 

Average Phenol Air 

Concentration 

(mg/m3) 

MOE 

Residential 0.30 air None 2.1 47 

changes per 

hour 

1500 24 hours 

24 hours 0.33 300 

Commercial 1.3 Air 

Changes per 

Hour 

1500 9 Hours None 0.31 320 

4.2 Post Application Exposure Assessment Using the EPA Risk Model 

During the emissions study, the chamber was ventilated at the rate of one air change per hour 

and the incoming air temperature was maintained at 38 C. This is a much lower ventilation rate 

and a much higher temperature than would occur inside a ventilation duct. Given these 

uncertainties a comparative assessment was done using the Antimicrobial Version of the EPA 

Risk Model and is presented below. This approach was also used previously in an assessment of 

the HVAC use of ABDAC (D323861 of June 30, 2006). 

The Antimicrobial version of the EPA Risk Model was designed specifically to assess the 

inhalation exposures that occur when biocides are used to treat HVAC ductwork. It is a 

modified version of the EPA Risk Model that uses a gas-phase-limited mass transfer model. The 

basic theoretical assumptions of this model are: (1) the antimicrobial agents are uniformly 

distributed on the surface of the ductwork, (2) emissions are controlled by gas-phase mass 

transfer, and (3) emissions during the application and carrier evaporation phase are insignificant. 

Assumptions Used

 The input assumptions that were used in the Risk Model are listed below. The building 

specific assumptions were taken from the Residential and Commercial Building Scenarios as 

defined on page 31 of the Antimicrobial Version Documentation. 

Building Specific Assumptions

• The residential scenario volume is 12,900 ft3 (300 m3) based upon EPA’s IAQ research 

house in North Carolina which is a typical ranch style three bedroom house built in the 

1970s. This house has an area of 1300 ft2

 (118 m2) and ceiling height of 10 ft. 

• The internal surface area of the residential scenario ductwork is 74 m2 based on the 

EPA’s research house. 

• The air exchange rate of the residential scenario is 0.30 air changes per hour (ACH) 

based on the EPA’s research house. 

• The commercial scenario building volume is 567,000 ft3 (16,055 m3) based upon a 

typical three story commercial building as specified in Rowe (1988). This building has a 

total area of 56700 ft2 (5267 m2). 

• The internal surface area of the commercial building ductwork is 26,000 ft2

 (2415 m2). 

Page 7 of 9 
• The air exchange rate of the commercial building is 1.3 ACH based on a mechanical 

ventilation rate 9,345 ft3/min (0.99 ACH) and a non-mechanical infiltration rate of 0.30 

ACH. 

Chemical Specific Assumptions

• The phenol concentration in the product is 15,600 ppm based on the fact that Sporidicin 

contains 1.56 percent phenol by weight and is applied undiluted. 

• The spray coverage is assumed to be 1500 ft2 per gallon. This assumption is based on 

coverage observed during the Sporicidin Emissions study when undiluted Sporicidin was 

sprayed onto metal plates. 

• The molecular weight of phenol is 94.1. 

• The vapor pressure of phenol is 0.35 mm Hg at 25 C as listed in the ACGIH TLV 

Documentation for Phenol. 

• The saturation concentration is 1771 mg/m3 based upon the above vapor pressure. 

• The molecular diffusivity is 0.028 m2/hr as calculated using FSG Method 1 in the EPA 

PARAMS Model. 

• The Unitless Henry’s Law Coefficient (HLC) is less than 0.001 based on the fact the 

HLC in terms of atm-m3

/mol is 0.00000033. (Note the exact number requires an 

extremely difficult unit conversion and is likely less than 0.001 and sensitivity testing in 

the Risk model indicated that the results did not change when the HLC ranged from 0.1 

to 0.0000001. 

Risk Summary 

 The results of the Risk model runs are included in Appendix A and are summarized in Table 

6. For the residential scenario, the estimated MOE is 6 if the exposure begins immediately after 

application and is of concern because it is less than the target MOE of 300. If the exposure does 

not begin until 16 hours after application; however, the MOE is above 300 which is not of 

concern. In a similar manner, the MOE is of concern for the commercial scenario if exposure 

begins immediately after application and is not of concern if exposure is postponed for 3 hours. 

Table 6 – Post Application Risk Summary Based on the Antimicrobial Risk Model

Scenario Air Exchange 

Rate 

Spray 

Coverage 

(ft2/ga) 

Averaging 

Time 

Waiting Time 

Before Re-entry 

Average Phenol Air 

Concentration 

(mg/m3) 

MOE 

Residential 0.30 air changes None 17.8 6 

per hour 

1500 24 hours 

16 hours 0.26 390 

Commercial 1.3 air changes None 3.9 26 

per Hour 

1500 9 Hours 

3 hours 0.20 500 

Page 8 of 9 
5.0 Risk Characterization 

There are many uncertainties with this risk assessment. These uncertainties include the 

following: 

• It is not known exactly how the Sporicidin is applied to ductwork because the label 

directions are extremely limited. Of particular concern is the spray coverage rate which 

is not specified either on the label or on the Directions for Use posted on the Sporicidin 

website. It is also unclear how good coverage of the ductwork could be achieved by 

fogging Sporicidin into the ductwork with the HVAC system in operation as listed in the 

directions for use. 

• The study that was submitted for Sporicidin has serious limitations which include the fact 

that the chamber was maintained at an elevated temperature of 38 C (i.e. 100 F) and that 

the first samples were not collected until four hours after application. Given these 

conditions, it is likely that a substantial amount of phenol was emitted before the first 

sample was collected. 

• The Antimicrobial Risk Model has not been adequately validated for duct treatment 

scenarios. The main concern is that model was derived from the Risk Model which had 

been developed and validated for emissions from surfaces such as painted walls that have 

much lower surface air velocities than ventilation ductwork. 

Given the above uncertainties it is recommended that additional data be collected to quantify 

phenol emissions and exposures. This data should include chamber studies to determine the 

emission rate of phenol under conditions of use and whole building studies to determine how 

these conditions affect real world phenol exposures. 

References

ACGIH (2001) Documentation of the Phenol TLV. 

Rowe III, W.H. (1988) HVAC Design Criteria, Options, Selection, R.S. Means Company, Inc. 

Kingston, MA. 

Page 9 of 9 
Appendix A - Occupational and Residential Exposure and Risk Assessment for the Duct Cleaning Use of Phenol (Sporicidin)

Spreadsheet 1 - Test Chamber Emission Data for Phenol from Sporicidine Applied to Metal Plates

Elapsed 

Exposure 

Hour

 Phenol 

Emission 

Factor 

(mg/m2/hr)

LN of 

Phenol 

Emission 

Factor

Area 

Treated 

(m2)

Phenol 

Emission 

Rate 

(mg/hr)

Chamber 

Volume 

(m3)

Chamber 

Loading 

(m2/m3)

Chamber 

Ventilation 

Rate (ACH)

Chamber 

Ventilation 

Rate 

(m3/hr)

Phenol in 

Air (mg/m3)

4 7.289 1.986 0.094 0.685 0.094 1.000 1 0.094 7.289

8 2.135 0.758 0.094 0.201 0.094 1.000 1 0.094 2.135

24 0.777 -0.252 0.094 0.073 0.094 1.000 1 0.094 0.77748 0.072 -2.635 0.094 0.007 0.094 1.000 1 0.094 0.07272 0.050 -2.996 0.094 0.005 0.094 1.000 1 0.094 0.05096 0.071 -2.642 0.094 0.007 0.094 1.000 1 0.094 0.071

FormulasPhenol Emission rate (mg/hr) = Measured Phenol Emission Factor (mg/m2/hr) * Treated Area (m2)Phenol Air Concentration (mg/m3) = Phenol Emission Rate (mg/hr) /Ventilation Rate (m3/hr)Study ConditionsProduct Loading 27.6 g/m2 2.57 g/ft2 Product Application Rate 28 gm/m3Coverage per Gallon: 1478 ft2/ga Product Application Rate 26 oz/1000 ft3Amount Product Applied 2.59 gm Ai Application Rate 431 mg/m3

Semilog Regression of Phenol Emission Factor

 (All Timepoints Included)

y = -0.0509x + 1.1756

R2 = 0.8019

-4-3-2-1

0123

0 24 48 72 96

Elapsed Time in Hours

Ln of Phenol Emission Factor

Semilog Regression of Phenol Emission Factor 

(First 48 Hours Timepoints Included)

y = -0.0966x + 1.993

R2 = 0.9685

-3-2-1

0123

0 8 16 24 32 40 48

Elapsed Time in Hours

Ln of Phenol Emission Factor
Appendix A - Occupational and Residential Exposure and Risk Assessment for the Duct Cleaning Use of Phenol (Sporicidin)

Spreadsheet 2 - Residential Building Phenol Air Concentration Following Duct Treatment (Estimated with IAQX Model 21)

Time (h)

Phenol 

(mg/m3)

Reentry 

Delay 

(Hours)

24 Hour 

Avg 

(mg/m3) MOE Assumptions: Value: Source:

0 0.00 0 2.14 47 Application Time 01 1.48 1 2.18 46 House Volume 300 m3 Antimicrobial Risk Model2 2.43 2 2.15 47 Air Exchange Rate 0.30 ACH Antimicrobial Risk Model3 3.01 3 2.07 48 Treated Area 74 m2 Antimicrobial Risk Model4 3.33 4 1.97 51 Application Phase None5 3.46 5 1.86 54 Model 21 E0 7.3 Semilog Regession of Phenol Data Time 0 to 48 hours6 3.46 6 1.73 58 Mode 21 k 0.097 Semilog Regession of Phenol Data Time 0 to 48 hours7 3.37 7 1.61 628 3.24 8 1.49 679 3.06 9 1.37 73

10 2.87 10 1.25 8011 2.67 11 1.15 8712 2.47 12 1.05 9613 2.28 13 0.95 10514 2.09 14 0.87 11515 1.92 15 0.79 12716 1.75 16 0.72 13917 1.60 17 0.65 15418 1.46 18 0.59 16919 1.32 19 0.54 18720 1.20 20 0.49 20621 1.09 21 0.44 22722 0.99 22 0.40 25123 0.90 23 0.36 27724 0.82 24 0.33 30525 0.7426 0.6727 0.6128 0.5529 0.5030 0.4531 0.4132 0.3733 0.3434 0.3035 0.2736 0.2537 0.2338 0.2039 0.1840 0.1741 0.1542 0.1443 0.1244 0.1145 0.1046 0.09247 0.08348 0.075

Residential Building Phenol Air Concentrations 

Estimated Using IAQX

0.00.51.01.52.02.53.03.54.0

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34

Elapsed Time in Hours

Phenol (mg/m3)
Appendix A - Occupational and Residential Exposure and Risk Assessment for the Duct Cleaning Use of Phenol (Sporicid

Spreadsheet 3 - Commercial Building Phenol Air Concentration Following Duct Treatment (Estimated with IAQX Model 21)

Time (h)

Phenol 

(mg/m3)

Reentry 

Delay 

(Hours)

24 Hour 

Avg 

(mg/m3) MOE Assumptions: Value: Source:

0 0.00 0 0.31 320 Application Time 01 0.58 1 0.32 316 Building Volume 16055 m3 Antimicrobial Risk Model2 0.68 2 0.30 339 Air Exchange Rate 1.3 ACH Antimicrobial Risk Model3 0.66 3 0.27 371 Treated Area 2415 M2 Antimicrobial Risk Model4 0.61 Application Phase None5 0.55 Model 21 E0 7.3 Semilog Regession of Phenol Data Time 0 to 48 hours6 0.50 Mode 21 k 0.097 Semilog Regession of Phenol Data Time 0 to 48 hours7 0.468 0.419 0.37

10 0.3411 0.3112 0.2813 0.2514 0.2315 0.2116 0.1917 0.1718 0.1519 0.1420 0.1221 0.1122 0.1023 0.0924 0.0825 0.0826 0.0727 0.0628 0.0629 0.0530 0.0531 0.04

Commercial Building Phenol Air Concentration

Esimated Using IAQX

0.00.51.01.52.02.53.03.54.0

0 2 4 6 8 10 12 14 16 18 20 22 24 

Elapsed Time in Hours

Phenol (mg/m3)
Appendix A - Occupational and Residential Exposure and Risk Assessment for the Duct Cleaning Use of Phenol (Sporicidin)

Spreadsheet 4 - Residential Building Phenol Air Concentration Following Duct Treatment (Estimated with the Antimicrobial Risk Mod

Time hrs 

House 

avg 

(mg/m3)

Rentry 

Delay 

(hours)

24 Hour 

TWA MOE

0 35 0 17.8 5.6 Mass emitted 46,670 mg

1 96 1 16.3 6.12 73 2 12.3 8.1 Inputs:3 54 3 9.3 11 Phenol Concentration 15600 ppm4 41 4 7.0 14 Coverage 1500 square feet per gallon5 30 5 5.3 19 Molecular Weight 94.16 24 6 4.1 25 Vapor Pressure 0.357 18 7 3.1 33 Saturation Concentration 1771 mm Hg8 14 8 2.3 43 Molecular Diffusivity 0.028 mg/m39 10.1 9 1.8 56 Henry's Law Constant 0.00001 m2/hr

10 7.9 10 1.4 7411 5.9 11 1.0 9712 4.5 12 0.78 12813 3.3 13 0.60 167 14 2.7 14 0.46 218 15 2.0 15 0.35 289 16 1.5 16 0.26 382 17 1.2 18 0.92 19 0.68 20 0.50 22 0.33 23 0.2524 0.2025 0.1526 0.1227 0.0928 0.0729 0.0630 0.0431 0.0332 0.0333 0.0234 0.0235 0.0136 0.0137 0.0138 0.0139 0.0140 0.00

Residential Building Phenol Air Concentrations Estimated Using the 

Antimicrobial Risk Model 

0

20406080

100120

0 2 4 6 8 10 12 14 16 18 20 22 

Time (hours)

Phenol (mg/m3)
Appendix A - Occupational and Residential Exposure and Risk Assessment for the Duct Cleaning Use of Phenol (Spor

Spreadsheet 5 - Commercial Building Phenol Air Concentration Following Duct Treatment (Estimated with the Antimic

Time hrs 

Bldg 

AVG 

(mg/m3)

1 Hour 

TWA

Reenty 

Delay 

(hours)

9 Hour 

TWA MOE

0.01 14 0 3.9 26 Mass emitted 1024600 mg

0.03 24 1 2.1 48 0.05 30 2 0.8 131 Inputs:0.07 34 3 0.2 420 Phenol Concentration in Product 15600 ppm0.09 37 Coverage 1500 square feet per gallon0.11 38 Molecular Weight 94.1

0.2 39 Vapor Pressure 0.35 mm Hg

0.31 36 Saturation Concentration 1771 mg/m30.41 32 Molecular Diffusivity 0.028 m2/hr0.51 29 Henry's Law Constant 0.00001 unitless0.61 260.71 240.79 220.89 200.99 18

1.0 17 162.0 6.5 122.9 2.4 4.53.9 0.91 1.54.9 0.32 0.566.0 0.11 0.196.9 0.043 0.0668.0 0.014 0.0258.9 0.0058 0.0089

10.0 0.0019 0.003411.0 0.0007 0.001111.8 0.0003 0.000412.9 0.0001 0.0002

Commercial Building Phenol Air Concentrations Estimated Using the 

Antimicrobial Risk Model 

05

1015202530354045

0 1 2 3 4 5 6 7 8 9 10 11 

Time (hours)

Phenol (mg/m3)