1.0 - Action Requested 

The Antimicrobial Division’s (AD) Regulatory Management Branch I has requested an 

Occupational and Residential Exposure Assessment of a previously unassessed use of phenol 

that is on the Sporicidin Disinfectant Solution Label (EPA 8383-3). This use is listed under the 

heading FOR FOGGING CLEAN ROOMS: See Sporicidin Bulletin No. 301. The following 

directions are included in Bulletin No. 301: 

 

“Sporicidin Brand Disinfectant solution is recommended for fogging articles and surfaces in 

 sealed rooms and cubicles as an adjunct to manual cleaning and disinfecting procedures. 

 Unscrew pump bottle and change [sic] the fogging device with the required volume of 

 solution. Seal all windows and doors. Set time for treatment cycle as recommended by 

 device manufacturer. Turn on device, leave room and reseal door. Do not allow anyone to 

 reenter room or cubicle for at least 2 hours after fogging cycle has been completed. Upon 

 reentering room or cubicle, follow regular cleaning and disinfecting procedures.” 

2.0 - Summary of Findings 

 Because the instructions on Bulletin 301 indicate that Sprocidin is applied by an automatic 

device, handler exposures occur only when filling the fogger reservoir. These exposures were 

assessed using the CMA data for the disinfectant open pouring scenario. This assessment 

indicated that the estimated dermal MOE of 300 and the estimated inhalation MOE of 1500 are 

above the respective target MOEs of 100 and 300, therefore the risks from dermal or inhalation 

exposures are not of concern. 

Post application inhalation exposures can occur after the fog has been applied and workers 

re-enter the treated areas. The instructions on Bulletin 301 indicate that the room must be sealed 

during application and no one is allowed to re-enter the room or cubicle for at least two hours 

after the fogging cycle is completed. An inhalation exposure assessment was conducted using 

the single chamber decay formula from the Multi-Chamber Concentration and Exposure Model 

(MCCEM). This assessment indicated that the MOEs rise to the target MOE of 300 after 3.3 air 

exchanges which takes 50 to 200 minutes depending upon the ventilation rate. 

 

Post application dermal exposures are not expected to be significant because a substantial 

portion of the applied fog will remain airborne long enough to be removed by ventilation. In 

addition, Bulletin 301 requires that regular cleaning and disinfecting be performed upon entering 

the room or cubicle which would further reduce surface residues. Phenol is also fairly volatile 

and any remaining residues would evaporate rather quickly with a Chinn evaporation time of 5.2 

hours. 

3.0 - 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 

Page 2 of 6 
exposure 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. There are no concerns regarding special sensitivity, 

therefore a data base uncertainty factor is not required.

Table 1 - Summary of Toxicological Doses for Phenol Occupational 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 

(26 mg/kg/day)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) 

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. 26 mg/kg/day = (0.1 mg/L * 10.26 L/hr/kg * 6 hrs/day) / 0.236 kg 

4.0 - Residential Exposures 

The existing Sporicidin label indicates that Sporidicin is used for fogging clean rooms. By 

definition, clean rooms are specialized production or research facilities that are designed to 

minimize product contamination and are not considered residential areas, therefore residential 

exposures are not anticipated. 

5.0 - Occupational Handler Exposures 

Because the instructions on Bulletin 301 indicate that Sprocidin is applied by an automatic 

device, handler exposures occur only when filling the fogger reservoir. These exposures were 

assessed using the CMA data for the disinfectant open pouring scenario. This data was collected 

as workers poured a 2 percent solution of glutaraldehyde from one gallon containers into pans 

Page 3 of 6 
for disinfection of medical instruments. 

The phenol handler exposures were assessed using the following assumptions. 

• Given that one gallon of Sporicidin can treat 30,000 square feet (or 240,000 cubic feet 

assuming an eight foot ceiling) it is likely that a handler would load at most five gallons of 

Sporocidin per day. 

• Sporicidin contains 0.13 lb active ingredient (ai) per gallon based upon the ai concentration 

of 1.56% and a density of 8.35 lbs per gallon. 

• Dermal exposures are assessed using the dermal unit exposure value of 36.5 mg/lb ai handled 

from the CMA database. This is the value for the disinfectant liquid pour scenario and is the 

mean of two samples. The handlers wore protective gloves during the sampling period. 

• Inhalation exposures are assessed using the inhalation unit exposure value of 1.89 mg/lb ai 

handled from the CMA database. This is the value for the disinfectant liquid pour scenario 

and is the mean of two samples. 

• The exposures would be short and intermediate term in duration because fogging is not done 

every day. 

The calculations and MOEs are included in Table 2. The dermal MOE of 300 exceeds the 

target MOE of 100 and the inhalation MOE of 1500 exceeds the target MOE of 300, therefore 

the risks from dermal or inhalation exposures are not of concern. 

Table 2 - Occupational Handler Risk Summary

Exposure 

Scenario 

Amount 

ai Handled 

per DayA

Exposure 

Pathway 

Unit 

ExposureB 

(mg/lb ai) 

ExposureC

(mg/day) 

DoseD,E 

(mg/kg/day) MOE F,G

Dermal 36.5 23.7 0.20 300 Loading Fogger 

– Liquid pour 0.65 lb 

Inhalation 1.89 1.23 0.0176 1500 

A. Amount ai handled per day = 0.13 lb ai per gallon * 5 gallons handled per day 

B. Unit exposures are from CMA, dermal exposures represent chemical resistant gloves being worn. 

C. Exposure (mg/lb) = Amount ai handled per day (lb) * Unit Exposure (mg/lb ai) 

D. Dermal dose (mg/kg/day) = [Exposure (mg/day) * Dermal Absorption Factor (0.5)] / Body weight (60 kg). 

E. Inhalation dose (mg/kg/day) = [Exposure (mg/day) * Inhalation Absorption Factor (1.0)] / Body weight (70 kg).

F. Dermal MOE = NOAEL/ Dose where NOAEL = 60 mg/kg/day. Target MOE = 100 

G. Inhalation MOE = LOAEL / Dose; where LOAEL = 26 mg/kg/day. Target MOE = 300 

6.0 - Occupational Post Application Exposures 

Inhalation Exposures

Post Application inhalation exposures can occur after the fog has been applied and workers 

re-enter the treated areas. The instructions on Bulletin 301 indicate that the room must be sealed 

during application and no one is allowed to re-enter the room or cubicle for at least two hours 

after the fogging cycle is completed. An inhalation exposure assessment was conducted using 

the single chamber decay formula from the Multi-Chamber Concentration and Exposure Model 

(MCCEM v1.2). This assessment was based upon the application parameters listed in the 

revised version of the Bulletin 301. The following assumptions were made: 

Page 4 of 6 
• The application is treated as an instant release scenario where the product becomes airborne 

as an aerosol and either remains airborne as an aerosol until it is removed by ventilation or it 

evaporates from the aerosol before it settles. Although it is acknowledged that some portion 

of the aerosol would settle onto horizontal surfaces, this fact is ignored for simplicity in the 

calculations and results in a conservative estimate of exposure. 

• The application rate is 1 gallon per 240,000 cubic feet (ft3) based upon listed rate of 1 gallon 

per 30,000 square feet and assuming an 8 foot ceiling. 

• The product contains 0.13 lb ai per gallon based upon the ai concentration of 1.56% and a 

density of 8.35 lbs per gallon. 

• The initial concentration is 8.7 mg/m3 based upon the following: 

(0.13 lb ai * 454,000 mg per lb) / (240,000 ft3 * 0.0283 m3 per ft3) 

• All openings such as windows and doors are closed and the ventilation system is turned off 

during the application of the fog. 

• After the fog has been applied and given time to penetrate, the ventilation system is 

activated. 

• The ventilation system provides an air exchange rate of 1.0 to 4.0 air changes per hour. 

The calculations are included in Appendix A and a summary of the results is included in 

Table 3. The MOEs rise to the target MOE of 300 after 3.3 air exchanges which takes 50 to 200 

minutes depending upon the ventilation rate. 

Table 3 – Phenol Air Concentrations Following Fogging Application

Initial 

Concentration 

Ventilation Rate 

(Air Changes per hour) 

Time to Reach MOE of 300 

(Minutes) 

Number of 

Air Changes 

1 200 

8.7 mg/m 2 100 3

4 50 

3.3 

Dermal Exposures

Post application dermal exposures are not expected to be significant because a substantial 

portion of the applied fog will remain airborne long enough to be removed by ventilation. In 

addition, Bulletin 301 requires that regular cleaning and disinfecting be performed upon entering 

the room or cubicle which would further reduce surface residues. Phenol is also fairly volatile 

and has a short Chinn evaporation time. The Chinn evaporation time is the time needed for 90 

percent of a substance applied as a thin film to evaporate and is based on the molecular weight 

and vapor pressure as outlined in the Residential SOPs. The Chinn formula is given below: 

Page 5 of 6 
D = 145/[(mw * vp)0.9546] 

Where: 

 D = Chinn evaporation time (hours) 

 mw = molecular weight (unitless) 

 vp = vapor pressure in torr 

Given that phenol has molecular weight of 94.1 and a vapor pressure of 0.35 mm hg at 25 C, 

the Chinn evaporation time for phenol is 5.2 hours at 25 C.

7.0 - Occupational Risk Characterization 

The assessment of the occupational handler risks are based on the CMA data for the liquid 

pour disinfectant scenario which consists of only two monitoring units. This scenario was 

chosen, however, because the chemical handled, glutaraldehyde, is similar in volatility to phenol 

and because glutaraldehyde, like Sporicidin, was handled in one gallon containers. The other 

liquid pour CMA data were either collected from operations, where larger containers that ranged 

in size from 5 gallon to 55 gallons, were handled and/or where chemicals that are less volatile 

than phenol were handled. 

The assessment of post application inhalation risk can be considered conservative because it 

is based entirely on contaminant removal by ventilation and does not consider removal by 

aerosol settling. This conservatism is reduced, however, by the fact that phenol is fairly volatile 

and will be emitted from the settled aerosols. 

Page 6 of 6 
Appendix A - ORE Assessment for the Existing Cleanroom Use of Phenol (Sporicidin)

Spreadsheet 1 - Phenol Fogger Post Application Exposures Estimated Using MCCEM 

Time 

(minutes)

Phenol 

(mg/m3) MOE Input Value Units

0 8.71 11 Amount Product Applied 1 Gallon

10 7.37 14 Percent ai 1.56 percent

20 6.24 16 Product Density 8.35 lb/ga

30 5.28 19 Amount ai Applied 0.13 lb

40 4.47 22 Amount ai 59138 mg

50 3.78 26

60 3.20 31 Treated Area 30000 sq feet

70 2.71 37 Ceiling Height 8 feet

80 2.29 44 Treated Volume 240000 cubic feet

90 1.94 51 Treated Volume 6792 cubic meters

100 1.64 61 Applied Concentration 8.71 mg/m3

110 1.39 72

120 1.18 85 Ventilation Rate 4000 CFM

130 1.00 100 Air Exchange Rate 1 ACH

140 0.84 118

150 0.71 140 EPA LOAEL 100 mg/m3

160 0.60 165 UF 300

170 0.51 195 EPA LOC 0.33 mg/m3

180 0.43 231

190 0.37 273

200 0.31 322

(1 Air Change per Hour)

0

1

2

3

4

5

6

7

8

9

10

0 30 60 90 120 150 180 210

Elasped Ventilation Time in Minutes

Phenol (mg/m3) 
Appendix A - ORE Assessment for the Existing Cleanroom Use of Phenol (Sporicidin)

Spreadsheet 2 - Phenol Fogger Post Application Exposures Estimated Using MCCEM 

Time 

(minutes)

Phenol 

(mg/m3) MOE Input Value Units

0 8.71 11 Amount Product Applied 1 Gallon

10 6.24 16 Percent ai 1.56 percent

20 4.47 22 Product Density 8.35 lb/ga

30 3.20 31 Amount ai Applied 0.13 lb

40 2.29 44 Amount ai 59138 mg

50 1.64 61

60 1.18 85 Treated Area 30000 sq feet

70 0.84 118 Ceiling Height 8 feet

80 0.60 165 Treated Volume 240000 cubic feet

90 0.43 231 Treated Volume 6792 cubic meters

100 0.31 322 Applied Concentration 8.71 mg/m3

Ventilation Rate 8000 CFM

Air Exchange Rate 2 ACH

EPA LOAEL 100 mg/m3

UF 300

EPA LOC 0.33 mg/m3

(2 Air Changes per Hour)

0

1

2

3

4

5

6

7

8

9

10

0 30 60 90 120 150 180 210

Elasped Ventilation Time in Minutes

Phenol (mg/m3) 
Appendix A - ORE Assessment for the Existing Cleanroom Use of Phenol (Sporicidin)

Spreadsheet 3 - Phenol Fogger Post Application Exposures Estimated Using MCCEM 

Time 

(minutes)

Phenol 

(mg/m3) MOE Input Value Units

0 8.71 11 Amount Product Applied 1 Gallon

10 4.47 22 Percent ai 1.56 percent

20 2.29 44 Product Density 8.35 lb/ga

30 1.18 85 Amount ai Applied 0.13 lb

40 0.60 165 Amount ai 59138 mg

50 0.31 322

Treated Area 30000 sq feet

Ceiling Height 8 feet

Treated Volume 240000 cubic feet

Treated Volume 6792 cubic meters

Applied Concentration 8.71 mg/m3

Ventilation Rate 16000 CFM

Air Exchange Rate 4 ACH

EPA LOAEL 100 mg/m3

UF 300

EPA LOC 0.33 mg/m3

(4 Air Changes per Hour)

0

1

2

3

4

5

6

7

8

9

10

0 30 60 90 120 150 180 210

Elasped Ventilation Time in Minutes

Phenol (mg/m3)