U.S. EPA Chemical Safety Advisory Committee (CSAC) 

Meeting

1-Bromopropane (1-BP) 

TSCA Work Plan Chemical 

Risk Assessment

Spray Adhesives, Dry Cleaning and Degreasing Uses

May 24-25, 2016

Arlington, VA
PRESENTATION OUTLINE

•Overview of Draft 1-BP Assessment

• Peer Review Charge

• Key Science Issues

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BACKGROUND

SLIDES 3 - 4 RELATE TO CHARGE QUESTIONS 1-1 THROUGH 1-2

Physical-Chemical Properties

− Volatile, vapor pressure 146.3 mmHg @ 20oC

− Boiling point 20oC at 760 mmHg

− Slightly soluble in water (2.45 g/L at 20oC)

− Low flammability

− Low environmental persistence

− Low bioconcentration and bioaccumulation potential 

| 3

Based on physical/chemical properties (high volatility) and environmental fate, 

combined with a low ecological hazard profile, risks associated with 

environmental and dermal exposures were not assessed. 
CONCEPTUAL MODEL

| 4

Effects

Effects

Manufacturing
OCCUPATIONAL EXPOSURE ASSESSMENT

SLIDES 5 – 30 RELATE TO CHARGE QUESTIONS 2-1 THROUGH 2-4

Objectives:

• Estimate number of exposed workers

• Assess inhalation exposure concentrations:

− 50th (central tendency) and 95th (high-end) percentile values 

− Estimate exposure for “workers” and “occupational nonusers”

− Estimate exposures pre-engineering controls or “pre-EC” (as a 

baseline) and post-EC to see risk reduction

• Calculate:

− acute concentrations (AC) 

− chronic concentrations [Average Daily Concentration (ADC) 

and Lifetime Average Daily Concentration (LADC)] 

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Method: “Top-Down” approach

1. Identify the NAICS codes for the industry sectors

2. Estimate total employment using US Census and Bureau of 

Labor Statistics data

3. Refine estimate of total by applying a factor (market 

penetration of 1-BP for that use)

Results:

− Spray Adhesives: 1,500 to 12,000

− Dry Cleaning and/or Spot Cleaning: 1,100 

− Vapor Degreasing: 4,700 to 24,000

− Cold Cleaning: not estimated

− Aerosol Degreasing: 2,500 to 12,000

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ESTIMATING NUMBER OF WORKERS
ESTIMATING INHALATION CONCENTRATIONS

Method:

1. Conduct comprehensive literature search for 

monitoring data 

2. Perform exposure modeling to augment and 

compare with exposure monitoring data

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ESTIMATING INHALATION CONCENTRATIONS –

SPRAY ADHESIVE

• 1-BP is used in spray adhesives for foam cushion 

manufacturing (e.g., the furniture industry) 

• Spray guns are used to spray-apply an adhesive onto 

flexible foam surfaces 

• Three NIOSH Health Hazard Evaluations (HHEs) 

provided monitoring data on 1-BP exposure from spray

adhesive use in foam cushion manufacturing 

• Two of the three HHEs also compare exposure pre- and 

post-engineering controls (post-EC)

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ESTIMATING INHALATION CONCENTRATIONS –

SPRAY ADHESIVE

• EPA defined the following: 

− Sprayers manually spray apply the 1-BP adhesive

− Non-sprayers do not directly perform spraying, but 

either handle the 1-BP adhesive (e.g., assemblers) 

or work in an area/department where spraying 

occurs

− Occupational non-users do not regularly perform 

work in an area of the facility where spraying occurs

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| 10

ESTIMATING INHALATION CONCENTRATIONS –

SPRAY ADHESIVE – MONITORING, PRE-EC

• Based on Data in NIOSH HHEs

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95th percentile

75

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Mean

25th percentile

5

th percentile

50th percentile 95th percentile

75

th percentile

Mean

5

th percentile 50th percentile
ESTIMATING INHALATION CONCENTRATIONS –

DRY CLEANING

• 1-BP is a solvent used in dry cleaning machines

• Workers are exposed when:

- Spot cleaning at dry cleaners

- Adding solvent to machines

- Removing loads from the machines

- Finishing and pressing

• Monitoring data available from NIOSH HHE of 1-BP use 

in four New Jersey commercial dry cleaning facilities

− Workers are operators of dry cleaning machines

− Occupational non-users are workers who do not spot clean 

or operate the machine

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ESTIMATING INHALATION CONCENTRATIONS –

DRY CLEANING – MONITORING, PRE-EC

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• Based on Data in NIOSH HHE

95th percentile

75

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Mean and 50th percentile

25th percentile

5

th percentile
ESTIMATING INHALATION CONCENTRATIONS –

DRY CLEANING - MODELING

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• A multi-zone modeling approach

• EPA/OPPT performed a Monte Carlo simulation
ESTIMATING INHALATION CONCENTRATIONS –

DRY CLEANING – MODELING, PRE-EC

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Model – Spot Cleaning Model – Machine Washing 

and Finishing

Model – O.N.U.

95th percentile

Mean & 50th percentile

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95th percentile

5

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75

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50th percentile

25th percentile
ESTIMATING INHALATION CONCENTRATIONS –

VAPOR DEGREASING

• EPA obtained exposure monitoring data from several 

sources (e.g., journal articles, NIOSH HHEs, OSHA IMIS 

Database, EPA SNAP data)

• Most data were for batch open-top vapor degreasers

• EPA categorized these data into pre-EC and post-EC

scenarios:

− Workers operate or perform maintenance tasks on 

the degreaser, such as draining, cleaning and 

charging the degreaser bath tank 

− Occupational non-users do not regularly handle 

1-BP or operate the degreaser but perform work in 

the area around the degreaser

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ESTIMATING INHALATION CONCENTRATIONS –

VAPOR DEGREASING – MONITORING, PRE-EC

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95th x percentile

50th percentile
ESTIMATING INHALATION CONCENTRATIONS –

VAPOR DEGREASING - MODELING

• Near-field / far-field model applied to vapor degreasing

• EPA/OPPT performed a Monte Carlo simulation

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ESTIMATING INHALATION CONCENTRATIONS –

VAPOR DEGREASING – MODELING, PRE-EC

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95th percentile

Mean and 50th percentile

95th percentile

50th percentile

Mean
ESTIMATING INHALATION CONCENTRATIONS –

COLD CLEANING DEGREASING

• Cold cleaners are non-boiling solvent degreasing units

• Types: 

− Batch-loaded, maintenance cold cleaner

− Dip tank 

• Emission sources: 

− Evaporation of the solvent from the solvent-to-air 

interface 

− “Carry out” of excess solvent on cleaned parts 

− Evaporative losses of the solvent during filling and 

draining of the machine 

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ESTIMATING INHALATION CONCENTRATIONS –

COLD CLEANING DEGREASING – MONITORING DATA

• EPA/OPPT obtained OSHA IMIS data for two facilities:

− The first facility manufactures decorative, 

architectural and church lighting, and uses 1-BP 

to clean parts in an immersion process in an area 

with general ventilation 

− The second facility manufactures parts for the 

aerospace industry and uses 1-BP in a degreasing 

tank equipped with a spray nozzle

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ESTIMATING INHALATION CONCENTRATIONS –

COLD CLEANING DEGREASING – MONITORING, PRE-EC

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n=10 n=1

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ESTIMATING INHALATION CONCENTRATIONS –

COLD CLEANING DEGREASING - MODELING

• Near-field/far-field modeling used

• Model approach and input parameters for 

cold cleaning are similar to vapor degreasing

• EPA/OPPT performed a Monte Carlo simulation

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ESTIMATING INHALATION CONCENTRATIONS –

COLD CLEANING DEGREASING – MODELING, PRE-EC

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95th percentile

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Mean
ESTIMATING INHALATION CONCENTRATIONS –

AEROSOL DEGREASING - MONITORING

• Involves use of an aerosolized solvent spray from a 

pressurized can

• Literature search identified monitoring data from 

two studies designed to simulate aerosol degreasing

• One tested an exposure scenario where the aerosol 

degreasing occurred inside a non-vented booth, 

with monitoring also conducted post-EC (e.g., using 

a vented booth)

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ESTIMATING INHALATION CONCENTRATIONS –

AEROSOL DEGREASING – MONITORING, PRE-EC

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ESTIMATING INHALATION CONCENTRATIONS –

AEROSOL DEGREASING - MODELING

• Near-field/Far-field modeling approach used

• EPA/OPPT performed a Monte Carlo simulation

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ESTIMATING INHALATION CONCENTRATIONS –

AEROSOL DEGREASING – MODELING, PRE-EC

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SUMMARY: 

OCCUPATIONAL EXPOSURE ESTIMATES, PRE-EC

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SUMMARY: 

OCCUPATIONAL EXPOSURE ESTIMATES, PRE-EC

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Occupational Use Scenario

Air Concentration (ppm)

Central Tendency

(50th percentile)

High End

(95th percentile)

Worker ONU Worker ONU

Spray Adhesive 131

(sprayer) 3

253

(sprayer) 129

Dry Cleaning 29.4 12.1 50.2 20.6

Vapor Degreasing 8.20 0.44 47.7 4.90

Cold Cleaning 13.7 2.6

(what if)

46.9 2.6 

(what if)

Aerosol Degreasing 16.1 N/D 31.6 N/D

Estimated 1-BP Air Concentrations (8-hr TWA) 

Based on Occupational Uses, Monitoring Data

Notes:

N/D = no data

“what if” is based on a single data point
ACUTE EXPOSURE CALCULATION

Acute exposures for workers are estimated as follows:

 =

×



where:

AC = acute concentration (8-hr TWA)

C = contaminant concentration in air (8-hr TWA)

ED = exposure duration (8-hr/day)

AT = averaging time (8-hr/day)

(Acute exposures for consumers are estimated 

assuming a 24 hr averaging time)

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   =

×××



Where:

ADC = average daily concentration (8-hr TWA) used for chronic

non-cancer risk calculations

LADC = lifetime average daily concentration (8-hr TWA) used for

chronic cancer risk calculations

C = contaminant concentration in air (8-hr TWA)

ED = exposure duration (8 hr/day)

EF = exposure frequency (260 days/yr)

WY = working years per lifetime (40 yr)

AT = averaging time (lifetime × 260 days/yr × 8 hrs/day) 

(lifetime is a 40 yr working lifetime for non-cancer risks; 

and a 70 yr lifetime for cancer risks)

CHRONIC EXPOSURE CALCULATIONS

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CONSUMER EXPOSURE ASSESSMENT

SLIDES 32 - 35 RELATE TO CHARGE QUESTIONS 3-1 THROUGH 3-2

Objectives:

• Identify Consumer Uses

− Aerosol Spray Adhesives

− Aerosol Spot Remover

− Aerosol Cleaner and Degreaser

• Estimate exposure levels 

− 50th (central tendency) and 90th (high-end) percentile values

− No consumer monitoring data available therefore modeling 

was used

• Calculate acute concentration using a 24-hr TWA 

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CONSUMER EXPOSURE MODELING

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• Model: Consumer Exposure Model module within 

EPA’s Exposure and Fate Assessment Screening Tool 

(E-FAST)

− Two zone representation of a house

• Zone 1: area where product is being used

• Zone 2: remainder of the house

• Default values used where applicable

• Exposure factors from EPA’s EFH 2011

• Consumer behavior inputs from 1987 Household 

Solvent Product Use Survey
CONSUMER EXPOSURE RESULTS

Consumer Use Scenario

Air Concentration (ppm)

Central Tendency

(50th percentile)

High End

(90th percentile)

User Non-User User Non-User

Aerosol Spray Adhesive 0.5 0.1 6 2

Aerosol Spot Remover 2 0.7 23 6

Aerosol Spray Cleaners and 

Degreasers:

Engine Degreasing Use 16 6 54 20

Brake Cleaning Use 5 2 22 8

Electronics Cleaning Use 0.5 0.2 7 3

| 34

Estimated 1-BP Air Concentrations (24-hr TWA) 

Based on Residential Indoor Uses
CONSUMER EXPOSURE SUMMARY

• Exposure estimates based on modeling

• Estimated exposures for all identified use scenarios

• Highest exposure potential identified for 1-BP use in 

aerosol spray cleaners and degreasers (e.g., engine 

degreasing and brake cleaning)

• Insufficient information to estimate the number of 

consumers for the evaluated uses

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HUMAN HEALTH HAZARD IDENTIFICATION AND

DOSE-RESPONSE ASSESSMENT

SLIDES 36 – 42 RELATE TO CHARGE QUESTIONS 4-1 THROUGH 4-4

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Study Performance 

Elements Assessment

Substance characterization Purity > 99%; stability monitored

Animal husbandry Rats (F344/N), mice (B6C3F1

); Adequate housing, animal care, and 

maintenance described

Study design quality

Rats and mice, both sexes, treated via inhalation for an exposure 

frequency and duration appropriate and relevant to determine 

exposure-related effect; appropriate spacing of doses; adequate 

number of animals/group

Clinical observations, 

necropsy and pathology

Clinical observations reported; all animals necropsied; all organs/tissues 

examined for gross lesions; histopathological evaluation of all major 

organs; adequate description of experimental design and pathology

procedures

Data reporting and 

statistical methods

Individual animal data provided in tabular format; tumors 

(benign/malignant) from same organ appropriately reported as 

combined; historical controls available for comparison

Studies informative for 

cancer assessment

Yes, for studies in rats and in mice

No major limitations

DATA QUALITY - ANIMAL TOXICITY

| 37
CONSIDERATIONS FOR REVIEWING DATA QUALITY IN

EPIDEMIOLOGICAL DATA

Study 

Population

Recruitment Strategy, inclusion/exclusion criteria; Number, time 

period, age/sex/other distribution, geographic area; Participation 

rates (at each stage), eligibility, comparison group selection, 

attrition rate; Follow up; Comparability (exposed and non-exposed)

Exposure Specific substance measured, analytical methods; Types of samples 

collected (matrix); Exposure groups defined, methods to assign; 

Limit of detection or level of quantitation, number of samples 

above/below; Exposure distribution (central tendency, range, etc); 

Potential for exposure misclassification; Use of TWAs for 

occupational studies; Empirical, estimated, or modeled exposures; 

Timing of collection; Validation of biomarkers 

Statistical 

Analysis

Power; Appropriateness of methods used; Reliable, consistent; 

Treatment of non-detects or < LOQ; Adjustment of variables; 

Explicit presentation of results; Significance levels clearly defined

Outcome Novel or validated assessment tools, appropriateness for study 

population; Blinding; Explicit, complete presentation of results; 

Timing; Confounding; Concordance of text with data results in 

tables; Potential bias

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CANCER HAZARD: 

PROBABLE MUTAGENIC MOA

• NTP Report on Carcinogens: 

“reasonably anticipated to be a carcinogen” 

• Cancer findings include significant increases in:

− Skin tumors in male rats

− Intestinal tumors in female rats

− Lung tumors in female mice

• Weight-of-evidence analysis found sufficient support for 

probable mutagenic MOA

• Multiple lines of evidence include in vitro, in vivo and 

structure activity relationships

• EPA concluded “likely human carcinogen”

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CANCER DOSE-RESPONSE ASSESSMENT

• Approach harmonized with NIOSH:

− Benchmark dose modeling (BMD) with BMR 0.1% added risk

− BMC and BMCL extrapolated to humans on body weight3⁄4

scaling and adjusted for exposure duration

• Lung tumors selected as basis for Inhalation Unit Risk 

(IUR)

• IUR calculated using linear approach:

IUR = BMR ÷ BMCL

= 0.001 ÷ 0.30 ppm

= 3 x 10-3 per ppm (7 x 10-7per μg/m3)

| 40
NON-CANCER DOSE-RESPONSE SUMMARY

| 41
HAZARD ID AND DOSE-RESPONSE

SUMMARY:

• PODs identified for selected non-cancer and cancer 

endpoints

• Selected most robust and sensitive HECs for each 

health effect domain

• Non-cancer HECs range from 25 - 150 ppm

• Derivation of the IUR based on increased incidence 

of lung tumors in female mice 

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RISK CHARACTERIZATION

SLIDES 43 – 55 RELATE TO CHARGE QUESTIONS 5-1 THROUGH 5-4

• Risks evaluated for acute/chronic inhalation exposures to 

workers and occupational non-users

• Risks evaluated for acute inhalation exposures to 

consumer users and non-users 

• Developmental toxicity selected as most sensitive 

endpoint for evaluating risks associated with acute

occupational and consumer exposure

• Cancer, developmental toxicity and neurotoxicity 

selected as the most sensitive endpoints for evaluating 

risks associated with chronic occupational exposure

| 43
RISK ESTIMATION: NON-CANCER EFFECTS

   =

   ()

 

Where:

MOE = Margin of exposure (unitless)

Hazard value (POD) = selected HECs (ppm) 

Human Exposure = inhalation exposure estimate for each use (ppm) 

MOE estimates compared to benchmark MOEs to determine risk 

(i.e., MOE < benchmark MOE indicates risk)

| 44

Risk No Risk
RISK ESTIMATION: NON-CANCER EFFECTS

For acute (non-cancer) exposure scenarios (workers and 

consumers):

• Developmental toxicity:

HEC = 31 ppm (8 hour TWA for workers)

HEC = 10 ppm (24 hour TWA for consumers)

For chronic (non-cancer) exposure scenarios (workers): 

• Developmental toxicity: HEC = 43 ppm

• Neurotoxicity: HEC = 25 ppm

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NON-CANCER RISK ESTIMATES FOR OCCUPATIONAL

INHALATION EXPOSURES - MONITORING DATA

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HEALTH EFFECT, 

ENDPOINT and 

STUDY

Worker Exposure 95th Percentile Estimates

Benchmark 

MOE

(Total UF) ACUTE MOE1 CHRONIC MOE1

OCCUPATIONAL USES

Spray 

Adhesives

Dry 

Cleaning

Vapor 

Degreasing 

Spray

Adhesives

Dry 

Cleaning

Vapor 

Degreasing

Developmental Toxicity

Decreased live litter size (F1) 

(WIL Research, 2001)

0.12 0.62 0.65 0.17 0.86 0.90 100

Neurotoxicity 

Decreased traction time 

(Honma et al., 2003)

N/A N/A N/A 0.10 0.50 0.50 1,000

Notes: 1MOEs (HEC in ppm/exposure estimate in ppm) lower than the Benchmark MOE (Total UF) 

indicate potential health risks and are denoted in bold.
NON-CANCER RISK ESTIMATES FOR CONSUMER INHALATION

EXPOSURES - MODELING DATA

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HEALTH 

EFFECT, 

ENDPOINT 

and STUDY

Acute 

HEC 

(ppm)

*

Consumer Exposure 90th Percentile Estimates

Benchmark 

MOE

(Total UF) AEROSOL SPRAY 

ADHESIVE MOE1

AEROSOL SPOT 

REMOVER MOE1

AEROSOL SPRAY CLEANERS AND DEGREASERS

ENGINE 

DEGREASER 

MOE1

BRAKE CLEANER 

MOE1

ELECTRONICS 

CLEANER MOE1

User2 NonUser3 User2 NonUser3 User2 NonUser3 User2 NonUser3 User2 NonUser3

Developmental 

Toxicity

Decreased live 

litter size (F1) 

(WIL Research, 

2001)

10 1.7 5 0.4 1.7 0.19 0.5 0.45 1.3 1.4 3.3 100

Notes:

* The acute consumer HECs were adjusted for 24 hour exposure 

1MOEs (HEC in ppm/exposure estimate in ppm) lower than the Benchmark MOE (Total UF) indicate 

potential health risks and are denoted in bold.

2MOEs for the use categories can be extended to different age groups; however, EPA believed the users of 

these products to be adults.

3All age categories (< 1 yrs; 1-2 yrs; 3-5 yrs; 6-10 yrs; 11-15 yrs; 16-20 yrs; and > 21 yrs)
CANCER RISK ESTIMATION

  =   × 

Where:

Human exposure = Inhalation estimate (LADC in ppm)

IUR = Inhalation unit risk (3 x 10-3 per ppm)

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Cancer risk estimates were calculated for:

• Chronic (i.e., occupational) exposure scenarios

• Not for acute (i.e., consumer) exposure scenarios
CANCER RISK BENCHMARKS

• 1x10-6: 1 chance in 1 million of an individual developing cancer 

(equivalent to 1 cancer case in 1 million)

• 1x10-5: 1 chance in 100,000 of an individual developing cancer 

(equivalent to 10 cancer cases in 1 million)

• 1x10-4: 1 chance in 10,000 of an individual developing cancer 

(equivalent to 100 cancer cases in 1 million)

| 49

   =   ×  

Where:

95th percentile cancer risk = 95th percentile exposure X IUR

Exposed population is the 95th percentile (i.e., 5 percent of the total 

number of workers) 

Workers are assumed to be exposed 8 hr/day, 260 day/yr for 40 years
ADDED CANCER RISK AT THE 95TH PERCENTILE FOR

INHALATION EXPOSURES

Increased cancer incidence: 5 to 40 workers 

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Occupational Use of 1-BP in Spray Adhesives -

Monitoring Data 
ADDED CANCER RISK AT THE 95TH PERCENTILE FOR

INHALATION EXPOSURES

Increased cancer incidence: < 1 to 4 workers

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Occupational Use of 1-BP in Dry Cleaning -

Monitoring Data
ADDED CANCER RISK AT THE 95TH PERCENTILE FOR

INHALATION EXPOSURES

Occupational Use of 1-BP in Vapor Degreasing -

Monitoring Data

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Increased cancer incidence: < 1 to 40 workers
CANCER RISK CONCLUSIONS

• Cancer risks to workers and occupational non-users 

are significantly increased at the occupational 

exposure concentrations/durations assumed for 

each scenario

• Risk calculations are based on conservative 

assumptions which may produce conservative 

cancer risk estimates 

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RISK CHARACTERIZATION SUMMARY

• Non-cancer risks identified for workers with acute and 

chronic exposures to 1-BP in spray adhesives, dry 

cleaning (including use in spot cleaning) and degreasing 

(vapor, cold cleaning and aerosol)

• Cancer risks identified for workers with chronic 

exposures to 1-BP in spray adhesives, dry cleaning 

(including spot cleaning) and degreasing (vapor, cold 

cleaning and aerosol)

• Non-cancer risks identified for consumers with acute 

exposures to 1-BP in spray adhesives, spot removers 

and degreasers 

-

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ASSUMPTIONS AND KEY SOURCES OF

UNCERTAINTY

• Sites used for exposure monitoring data were not 

selected randomly 

• Exposure modeling approaches employed knowledgebased assumptions

• Risk determinations predicated on the presumed 

relevance of effects observed in rodents to humans

• Developmental effects may result from a single exposure 

during a critical period

• Uncertainty regarding the proposed mode of action 

• Dermal exposures were not quantified

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EPA 1-BP RISK ASSESSMENT TEAM

Katherine Anitole 

Stan Barone Jr.

Chris Brinkerhoff 

Judith Brown

Anjali Lamba 

Greg Macek

Paul Matthai

Albert Monroe 

Ginger Moser

Alie Muneer 

Tina Ndoh 

Nhan Nguyen

Sharon Oxendine 

Andrea Pfahles-Hutchens 

Justin Roberts 

Nina Simeonova

Christina Thompson

Eva Wong 

Yin-Tak Woo

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Peer Review Charge Questions

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GENERAL ISSUES ON THE RISK ASSESSMENT

Question 1-1: Please comment on whether the information 

provided in Section 1 (Background and Scope) is appropriate 

and accurately characterizes the fit for purpose nature of this 

assessment for TSCA related uses? Please provide any specific 

suggestions for improving the clarity and transparency of the 

background information that describes scope and limits of the 

assessment.

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GENERAL ISSUES ON THE RISK ASSESSMENT

Question 1-2: Please comment on the scope of the 

assessment, in particular the conceptual model resulting from 

EPA/OPPT’s problem formulation. Please provide any other 

significant literature, reports, or data that would be useful to 

complete this characterization and that may support 

expansion or refinement of the scope of this assessment.

59
OCCUPATIONAL EXPOSURE ASSESSMENT

Question 2-1: Please comment on the approaches used, and 

provide any specific suggestions or recommendations for 

alternative approaches, models, or information (references) 

that could be considered by EPA/OPPT for improving the 

workplace exposure assessment, including estimations for 

bystander/non-users (e.g., women of child-bearing age). 

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OCCUPATIONAL EXPOSURE ASSESSMENT

Question 2-2: Please comment on whether there are any 

additional occupational exposure scenarios that EPA/OPPT 

could address that have not already been quantified. Please 

also provide specific references and/or data to address such 

additional exposures.

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OCCUPATIONAL EXPOSURE ASSESSMENT

Question 2-3: For the exposure assessments based on 

monitoring data, are you aware of any additional sources of 

occupational exposure monitoring data that EPA/OPPT could 

consider in its assessment? If so, please provide specific 

literature, reports, or data that would help us refine the 

exposure assessment.

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OCCUPATIONAL EXPOSURE ASSESSMENT

Question 2-4: For the exposure assessments based on 

modeling, are you aware of any additional sources of data that 

EPA/OPPT could consider in deriving the parameter values 

used in the modeling? If so, please provide relevant literature, 

reports, or data that would help us refine the parameters used 

in the modeling

63
CONSUMER EXPOSURE ASSESSMENT

Question 3-1: Please comment on the approach used and 

provide any specific suggestions or recommendations for 

alternative approaches, models, or use information (e.g., 

information on duration, number of user events, amount used) 

that could be considered by EPA/OPPT in developing and /or 

refining the exposure assumptions and estimates for spray

adhesives, aerosol spot removers and aerosol spray cleaners 

and degreasers. 

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CONSUMER EXPOSURE ASSESSMENT

Question 3-2: Exposure estimates were developed for three 

consumer uses: spray adhesives, aerosol spot removers and 

aerosol spray cleaners and degreasers. All products are aerosol 

sprays and appear to be available for sale and use by 

consumers in the U.S. There were no current reliable data 

regarding the consumer exposure scenarios. Please comment 

on the consumer uses selected for this assessment and 

provide any specific suggestions or recommendations for 

additional uses (including information on duration, number of 

user events, amount used) that could be considered for 

evaluation. 

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HAZARD AND DOSE-RESPONSE ASSESSMENTS

Question 4-1: EPA/OPPT concluded in the risk assessment that 

1-BP carcinogenesis occurs through a probable mutagenic 

mode of action based on the totality of the available 

data/information and the WOE. Please comment whether the 

cancer hazard assessment has adequately described the WOE 

regarding the mutagenic mode of action.

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HAZARD AND DOSE-RESPONSE ASSESSMENTS

Question 4-2: EPA/OPPT identified liver toxicity, kidney toxicity, 

reproductive/developmental toxicity, and neurotoxicity in the 

risk assessment as adverse human health effects for risk 

characterization. EPA/OPPT used these endpoints to calculate 

PODs to assess non-cancer risks associated with chronic 

inhalation exposures. As part of the review, please comment 

on the choice of these endpoints as PODs for assessing risks in 

humans associated with acute and chronic inhalation 

exposures to 1-BP. Are there other data that EPA/OPPT could 

have considered for the hazard identification and dose 

response associated with chronic inhalation exposures? If so, 

please provide specific data and references. 

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HAZARD AND DOSE-RESPONSE ASSESSMENTS

Question 4-3: Please comment on the WOE analysis for the 

choices of non-cancer endpoints for the acute and chronic risk 

scenarios. Please provide additional data, data interpretation 

or information that would have informed the WOE analysis 

and selection of critical studies for the PODs. 

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HAZARD AND DOSE-RESPONSE ASSESSMENTS

Question 4-4: Typically, EPA uses the benchmark dose 

modeling software (BMDS) with a BMR of 10% and the models 

are restricted to multistage models or the broader suite of 

dichotomous models in BMDS and a single best model is 

chosen for the POD. EPA/OPPT used an alternative approach to

calculate the cancer POD versus the standard approach of 

choosing best fit model. Briefly, EPA/OPPT used a model 

averaging approach considering multiple benchmark dose 

models to calculate the POD at a benchmark response (BMR) 

level of 0.1%. Please comment on the assumptions, strengths 

and weaknesses of the model averaging approach for 

determining the POD in the cancer assessment. 

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RISK CHARACTERIZATION

Question 5-1: EPA/OPPT interpreted the endpoint of decreases in 

live litter size following exposure to 1-BP before and during 

gestation, as a surrogate for frank developmental effects in relevant 

to humans per EPA’s Guidelines for Developmental Toxicity Risk 

Assessment. EPA/OPPT used this endpoint to calculate a point of 

departure (POD) to assess non-cancer risks associated with acute 

inhalation exposures to 1-BP. Please comment on the assumptions, 

strengths and weaknesses of the MOE approaches used to estimate 

the non-cancer risks to workers and occupational non-users 

following acute inhalation exposures to 1-BP, including the MOEs 

presented in the document. Please comment on the assumptions, 

strengths and weaknesses of the MOE approaches used to estimate 

risks to consumers following acute inhalation exposures; including 

non-users (e.g., bystanders who may be children, or women of 

childbearing age). Specifically, please comment on the decision to 

limit the analysis to acute exposures without residual concerns 

between events and what data could critically inform modifying this 

approach for consumers. Please comment on the selection of 

uncertainty factor values in deriving the benchmark MOE for acute 

inhalation exposures. 

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RISK CHARACTERIZATION

Question 5-2: Please comment on the assumptions, strengths 

and weaknesses of the MOE approaches used to estimate the 

non-cancer risks to workers and occupational non-users 

following chronic inhalation exposures to 1-BP, including the 

MOEs presented in the document. Please comment on the 

selection of uncertainty factor values in deriving the 

benchmark MOE for chronic inhalation exposures. 

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RISK CHARACTERIZATION

Question 5-3: Please comment on the assumptions, strengths 

and weaknesses of the approach used to estimate added 

lifetime cancer risks to workers which EPA/OPPT-derived from 

an inhalation unit risk based on lung tumors in female mice for 

estimating incremental or added individual lifetime cancer risk. 

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RISK CHARACTERIZATION

Question 5-4: Please comment on whether the risk 

characterization has adequately described the assumptions, 

uncertainties and data limitations in the methodology used to 

assess risks from 1-BP. Please comment on whether this 

information and risk conclusions are presented in a logical, 

transparent manner and provide suggestions that could 

increase clarity in the risk characterization.

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