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policy. 1

2

3

4

5

6



## I MMEDIATELY 

## D ANGEROUS TO 

## L IFE OR 

## H EALTH 

## (IDLH) V ALUE 

## P ROFILE 7

8

9

10



### FOR 11

12

13

14



## N-B UTYL 

## A CRYLATE 15

16

17

18



## [CAS NO



## . 141-32-2] 19

20

21

22

23

24

25

Department of Health and Human Services 26

Centers for Disease Control and Prevention 27

National Institute for Occupa tional Safety and Health 28External Review Draft

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Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. 

## D ISCLAIMER 1

Mention of any company or product does not constitute endorsement by the National Institute for Occupational 2

Safety and Health (NIOSH). In add ition, citations of Web sites extern al to NIOSH do not constitute NIOSH 3

endorsement of the sponsoring organizations or thei r programs or products. Furthermore, NIOSH is not 4

responsible for the content of these Web sites. 5

6



## O RDERING 

## I NFORMATION 7

This document is in the public domain and may be freely copied or reprinted. To receive NIOSH documents or 8

other information about occupational safet y and health topics, contact NIOSH at 9

Telephone: 1-800-CDC-IN FO (1-800-232-4636) 10

TTY: 1-888-232-6348 11

E-mail: cdcinfo@cdc.gov 12

13

or visit the NIOSH Web site at www.cdc.gov/niosh. 14External Review Draft

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Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. 

## Foreword 1

Chemicals are a ubiquitous component of the modern wo rkplace. Occupational exposures to chemicals have the 2

potential to adversely affect the health and lives of workers. Acute or short-term exposures to high concentrations 3

of some airborne chemicals have the ability to quickly overwhelm workers, resulting in a spectrum of undesirable 4

health outcomes that may inhibit the ability to escape from the exposure envi ronment (e.g., irritation of the eyes 5

and respiratory tract or cognitive impairment), cause severe irreversible effects (e.g., damage to the respiratory 6

tract or reproductive toxicity), and in extreme cases, cause death. Airborne concentrations of chemicals capable 7

of causing such adverse health effects or of impeding escape from high-risk conditions may arise from a variety of 8

non-routine workplace situations , including special wo rk procedures (e.g., in confined spaces), industrial 9

accidents (e.g., chemical spills or explosions), and chemical releases into the community (e.g., during 10

transportation incidents or other uncontrolled-release scenarios). 11

12

The “immediately dangerous to life or health air concen tration values (IDLH values)” developed by the National 13

Institute for Occupational Safety a nd Health (NIOSH) characterize these high-risk exposure concentrations and 14

conditions [NIOSH 2013]. IDLH values are based on a 30-minute exposure duration and have traditionally 15

served as a key component of the decision logic for the selection of respiratory protection devices [NIOSH 2004]. 16

Occupational health professionals have employed these values beyond their initial purpose as a component of the 17

NIOSH Respirator Selection Logic to assist in developi ng Risk Management Plans for non-routine work practices 18

governing operations in high-risk envi ronments (e.g., confined spaces) and the development of Emergency 19

Preparedness Plans. 20

21

The approach used to derive IDLH values for high priority chemicals is outlined in the NIOSH Current 22

Intelligence Bulletin (CIB) 66: Derivation of Immediately Da ngerous to Life or Health Values [NIOSH 2013]. 23

CIB 66 provides 1) an update on the scientific basis a nd risk assessment methodology used to derive IDLH 24

values, 2) the rationale and derivati on process for IDLH values, and 3) a demonstration of the derivation of 25

scientifically credible IDLH values using available data resources. 26

27

The purpose of this technical report is to present the IDLH value for n-butyl acrylate (CAS # 141-23-2). The 28

scientific basis, toxicologic data and risk assessment appr oach used to derive the ID LH value are summarized to 29

ensure transparency and scientific credibility. 30

31

John Howard, M.D. 32

Director 33

National Institute for Occupa tional Safety and Health 34External Review Draft

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policy. Centers for Disease Control and Prevention 1External Review Draft

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policy. 

## Contents 1

FOREWORD

............................................................................................................................... ................................. III 2

ABBREVIATIONS

............................................................................................................................... ........................ VI 3

GLOSSARY

............................................................................................................................... .................................. VII 4

ACKNOWLEDGMENTS

............................................................................................................................... .............. XI 5

1.0 INTRODUCTION

............................................................................................................................... ............... 1 6

1.1 O VERVIEW OF THE IDLH V ALUE FOR N -B UTYL A CRYLATE

....................................................................................... 1 7

1.2 P URPOSE

............................................................................................................................... ...................................... 1 8

1.3 G ENERAL S UBSTANCE I NFORMATION

......................................................................................................................... 1 9

2.0 ANIMAL TOXICITY DATA

............................................................................................................................. 4 10

3.0 HUMAN DATA

............................................................................................................................... .................. 7 11

4.0 SUMMARY

............................................................................................................................... ......................... 7 12

5.0 REFERENCES

............................................................................................................................... ................... 8 13

14

15

16

17

18External Review Draft

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policy. 

## Abbreviations 1

2

ACGIH American Conference of Gove rnmental Industrial Hygienists 3

AEGL Acute Exposure Guideline Levels 4

AIHA American Industrial Hygiene Association 5

BMC benchmark concentration 6

BMCL benchmark concentra tion lower confidence limit 7

C° Celsius 8

C ceiling 9

CAS chemical abstract service 10

ERPG Emergency Response Planning Guidelines 11

IDLH immediately dangerous to life or health 12

LC 50 median lethal concentration 13

LC Lo lowest concentration of a chemical that caused death in humans or animals 14

LEL lower explosive limit 15

LOAEL lowest observed adverse effect level 16

mg/m 3 milligram(s) per cubic meter 17

mmHg millimeter(s) of mercury 18

NAC National Advisory Committee 19

NAS National Academy of Sciences 20

NIOSH National Institute for O ccupational Safety and Health 21

NOAEL no observed adverse effect level 22

OSHA Occupational Safety and Health Administration 23

PEL permissible exposure limit 24

ppm parts per million 25

RD 50 concentration of a chemical in the air that is estimated to cause a 50% decrease in the respiratory 26

rate 27

REL recommend exposure limit 28

SCP Standard Completion Program 29

STEL short term exposure limit 30

TLV threshold limit value 31

TWA time weighted average 32

UEL upper explosive limit 33

WEEL workplace environmental exposure level 34External Review Draft

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policy. 

## Glossary 1

2

Acute Exposure : Exposure by the oral, dermal, or inhalation route for 24 hours or less. 3

Acute Exposure Guideline Levels (AEGLs) : Threshold exposure limits for the general public applicable to 4

emergency exposure periods ranging from 10 minutes to 8 hours. AEGL-1, AEGL 2, and AEGL-3 are 5

developed for five exposure periods (10 and 30 minutes, 1 hour, 4 hours, and 8 hours) and are distinguished 6

by varying degrees of severity of toxic effects ranging fro m transient, reversible effects to life-threatening 7

effects [NAS 2001]. AEGLs are intended to be guideline le vels used during rare events or single once-in-a8

lifetime exposures to airborne concentrations of acu tely toxic, high-priority chemicals [NAS 2001]. The 9

threshold exposure limits are designed to protect the general population, including the elderly, children or 10

other potentially sensitive groups that are generally not considered in the development of workplace exposure 11

recommendations (additional information av ailable at http://www.epa.gov/oppt/aegl/). 12

Acute Reference Concentration (RfC) : An estimate (with uncertainty spa nning perhaps an order of magnitude) 13

of a continuous inhalation exposure for an acute dur ation (24 hours or less) of the human population 14

(including sensitive subgroups) that is li kely to be without an appreciable risk of deleterious effects during a 15

lifetime. It can be derived from a NOAEL, LOAEL, or benchmark concentration, with uncertainty factors 16

(UFs) generally applied to reflect li mitations of the data used. Generally used in USEPA noncancer health 17

assessments [USEPA 2014]. 18

Acute Toxicity : Any poisonous effect produced within a short period of time following an exposure, usually 24 19

to 96 hours. 20

Adverse Effect : A substance-related biochemical change, functional impairment, or pathologic lesion that affects 21

the performance of an organ or system or alters the ab ility to respond to additional environmental challenges. 22

Benchmark Dose/Concentration (BMD/BMC) : A dose or concentration that produces a predetermined change 23

in response rate of an effect (called the benchmar k response, or BMR) compared to background [USEPA 24

2014] (additional information available at http://www.epa.gov/ncea/bmds/). 25

Benchmark Response (BMR) : A predetermined change in response rate of an effect. Common defaults for the 26

BMR are 10% or 5%, reflecting study design, da ta variability, and sensitivity limits used. 27

BMCL : A statistical lower confidence limit on th e concentration at the BMC [USEPA 2014]. 28

Bolus Exposure : A single, relatively large dose. 29

Ceiling Value (“C”) : U.S. term in occupational exposure indicati ng the airborne concentration of a potentially 30

toxic substance that should never be exceeded in a worker’s breathing zone. 31

Chronic Exposure : Repeated exposure for an extended period of time. Typically exposures are more than 32

approximately 10% of life span for humans and >90 days to 2 years for laboratory species. 33

Critical Study : The study that contributes most significantly to the qualitative and quantitative assessment of risk 34

[USEPA 2014]. 35

36

Dose : The amount of a substance available for interactions with metabolic processes or biologically significant 37

receptors after crossing the outer boundary of an organism [USEPA 2014]. 38

ECt 50 : A combination of the effective concentration of a s ubstance in the air and the exposure duration that is 39

predicted to cause an effect in 50% (one half) of the experimental test subjects. 40External Review Draft

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information quality guidelines. It has not been formally di sseminated by the National Institute for Occupational

Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. Emergency Response Planning Guidelines (ERPGs) : Maximum airborne concentrations below which nearly all 1

individuals can be exposed without experiencing health effects for 1-hour exposure. ERPGs are presented in a 2

tiered fashion with health effects ranging from mild or transient to serious, irreversible, or life threatening 3

(depending on the tier). ERPGs are developed by the Am erican Industrial Hygiene Association [AIHA 2006]. 4

Endpoint : An observable or measurable biological event or si gn of toxicity ranging from biomarkers of initial 5

response to gross manifestations of clinical toxicity. 6

Exposure : Contact made between a chemical, physical, or biological agent and the outer boundary of an 7

organism. Exposure is quantified as the amount of an agent available at the exchange boundaries of the 8

organism (e.g., skin, lungs, gut). 9

Extrapolation : An estimate of the response at a point outside the range of the experimental data, generally 10

through the use of a mathematical model, although qualitative extrapol ation may also be conducted. The 11

model may then be used to extrapolate to res ponse levels that cannot be directly observed. 12

Hazard : A potential source of harm. Hazard is distinguished from risk, which is the probability of harm under 13

specific exposure conditions. 14

Immediately Dangerous to Life or Health (IDLH) condition : A situation that poses a threat of exposure to 15

airborne contaminants when that exposure is likely to cause death or immediate or delayed permanent adverse 16

health effects or prevent escape from such an environment [NIOSH 2004, 2013]. 17

IDLH value : A maximum (airborne concentration) level above which only a highly reliable breathing apparatus 18

providing maximum worker protection is permitted [NIOSH 2004, 2013]. IDLH values are based on a 30- 19

minute exposure duration. 20

LC 01 : The statistically determined concentra tion of a substance in the air that is estimated to cause death in 1% of 21

the test animals. 22

LC 50 : The statistically determined concentr ation of a substance in the air that is estimated to cause death in 50% 23

(one half) of the test animals; median lethal concentration. 24

LC LO : The lowest lethal concentration of a substance in the air reported to cause death, usually for a small 25

percentage of the test animals. 26

27

LD 50 : The statistically determined lethal dose of a substance that is estimated to cause death in 50% (one half) of 28

the test animals; median lethal concentration. 29

LD LO : The lowest dose of a substance that causes death, usua lly for a small percentage of the test animals. 30

LEL : The minimum concentration of a gas or vapor in air, below which propagation of a flame does not occur in 31

the presence of an ignition source. 32

Lethality : Pertaining to or causing death; fatal; referring to th e deaths resulting from acute toxicity studies. May 33

also be used in lethality threshold to describe the poi nt of sufficient substance concentration to begin to cause 34

death. 35

Lowest Observed Adverse Effect Level (LOAEL) : The lowest tested dose or concentration of a substance that 36

has been reported to cause harmful (adverse) health effects in people or animals. 37External Review Draft

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information quality guidelines. It has not been formally di sseminated by the National Institute for Occupational

Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. Mode of Action : The sequence of significant events and processes that describes how a substance causes a toxic 1

outcome. Mode of action is distinguished from the more detailed mechanism of action, which implies a more 2

detailed understanding on a molecular level. 3

No Observed Adverse Effect Level (NOAEL) : The highest tested dose or concentration of a substance that has 4

been reported to cause no harmful (adverse) health effects in people or animals. 5

Occupational Exposure Limit (OEL) : Workplace exposure recommendations developed by governmental 6

agencies and non-governmental organizations. OELs are intended to represent the maximum airborne 7

concentrations of a chemical substance below wh ich workplace exposures should not cause adverse health 8

effects. OELs may apply to ceiling, short-term (STELs), or time-weighted average (TWA) limits. 9

Peak Concentration : Highest concentration of a substance record ed during a certain period of observation. 10

Permissible Exposure Limit (PEL) : Occupational exposure limits devel oped by OSHA (29 CFR 1910.1000) or 11

MSHA (30 CFR 57.5001) for allowable occupational air borne exposure concentr ations. PELs are legally 12

enforceable and may be designated as ceiling, STEL, or TWA limits. 13

14

Point of Departure (POD) : The point on the dose–response curve fro m which dose extrapolation is initiated. 15

This point can be the lower bound on dose for an estim ated incidence or a change in response level from a 16

concentration-response model (BMC), or it can be a NOAEL or LOAEL for an observed effect selected from 17

a dose evaluated in a health e ffects or toxicology study. 18

RD 50 : The statistically determined concentr ation of a substance in the air that is estimated to cause a 50% (one 19

half) decrease in the respiratory rate. 20

Recommended Exposure Limit (REL) : Recommended maximum exposure limit to prevent adverse health 21

effects based on human and animal studies and established for occupational (up to 10-hour shift, 40-hour 22

week) inhalation exposure by NIOSH. RELs may be designated as ceiling, STEL, or TWA limits. 23

Short-Term Exposure Limit (STEL) : A worker’s 15-minute time-weighted average exposure concentration that 24

shall not be exceeded at any time during a work day. 25

Target Organ : Organ in which the toxic injury manifests in terms of dysfunction or overt disease. 26

Threshold Limit Values (TLVs®) : Recommended guidelines for occupa tional exposure to airborne 27

contaminants, published by the American Conference of Governmental Industrial Hygienists (ACGIH). TLVs 28

refer to airborne concentrations of chemical substa nces and represent conditions under which it is believed 29

that nearly all workers may be repeatedly exposed, da y after day, over a working lifetime, without adverse 30

effects. TLVs may be designated as ceiling, short-term (STELs), or 8-hr TWA limits. 31

Time-Weighted Average (TWA) : A worker’s 8-hour (or up to 10-hour) time-weighted average exposure 32

concentration that shall not be exceeded during an 8- hour (or up to 10-hour) work shift of a 40-hour week. 33

The average concentration is weighted to take into ac count the duration of different exposure concentrations. 34

Toxicity : The degree to which a substance is able to ca use an adverse effect on an exposed organism. 35

36

Uncertainty Factors (UFs) : Mathematical adjustments applied to th e POD when developing IDLH values. The 37

UFs for IDLH value derivation are determined by consid ering the study and effect used for the POD, with 38

further modification based on the overall database. 39External Review Draft

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information quality guidelines. It has not been formally di sseminated by the National Institute for Occupational

Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. Workplace Environmental Exposure Levels (WEELs) : Exposure levels developed by the American Industrial 1

Hygiene Association (AIHA) that provide guidance fo r protecting most workers from adverse health effects 2

related to occupational chemical expos ures expressed as a TWA or ceiling limit. 3

4External Review Draft

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Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. 

## Acknowledgments 1

2

This document was developed by the Education and Info rmation Division (Paul Schulte, Ph.D., Director). G. 3

Scott Dotson, Ph.D., was the project officer and lead NIOS H author for this technical report. The basis for this 4

document was a report contracted by NIOSH and prepar ed by Andrew Maier, Ph.D., Ann Parker, and Lynn 5

Haber, Ph.D. (Toxicology Excellen ce for Risk Assessment [TERA]). 6

7

Education and Information Division 8

Devin Baker, M.Ed. 9

Charles L. Geraci, Ph.D. 10

Thomas J. Lentz, Ph.D. 11

Richard Niemeier, Ph.D. 12

Chris Sofge, Ph.D. 13

14

NIOSH would like to acknowledge the contribution of th e following subject matter experts for their critical 15

technical review of this report. 16

17

Mary A. Fox, Ph.D., Assistant Professor; Co-Direct or, Risk Sciences and Public Policy Institute; 18

Department of Health Policy and Management, Bl oomberg School of Public Health, Johns Hopkins 19

University 20

21

Richard B. Schlesinger, Ph.D., Fellow A.T.S., Senior Associate Dean for Academic Affairs and Research 22

Professor of Biology, Dyson College of Arts and Sciences, Pace University 23External Review Draft

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information quality guidelines. It has not been formally di sseminated by the National Institute for Occupational

Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. 

## 1.0 Introduction 1



## 1.1 Overview of the IDLH Value for n-Butyl Acrylate 2

3

IDLH Value: 113 ppm 4

5

Basis for IDLH Value: The IDLH value for n-butyl acrylate is based on the 30-minute RD 50 (concentration 6

estimated to result in a 50% depression in breathing rate ) of 340 ppm in mice [Kirkpatrick 2003]. This effect is 7

classified as potentially escape impairing. Application of an uncertainty factor of 3 to account for extrapolation 8

from a threshold for escape-impairing effects in animals, animal to human differences, and human variability, 9

results in an IDLH value of 113 ppm. 10

11



## 1.2 Purpose 12

13

This IDLH Profile presents (1) a brief summary of technical data associated with acute inhalation exposures to n14

butyl acrylate and (2) the rationale behind the Immediately Dangerous to Life or Hea lth (IDLH) value for n-butyl 15

acrylate. IDLH values are developed based on the scientific rationale and logic outlined in the NIOSH Current 16

Intelligence Bulletin (CIB) 66: Derivation of Immediately Dangerous to Life or Health (IDLH) values [NIOSH 17

2013]. As described in CIB 66, NIOSH performs in-depth lite rature searches to ensure that all relevant data from 18

human and animal studies with acute exposures to the subs tance are identified. Information included in CIB 66 on 19

the literature search includes pertinent databases, key terms, and guides for evaluating data quality and relevance 20

for the establishment of an IDLH value. The information that is identified in the in -depth literature search is 21

evaluated with general considerations that include description of studies (i.e., species, study protocol, exposure 22

concentration and duration), health endpoint evaluated, and critical e ffect levels (e.g., NOAELs, LOAELs, LC 50 23

values). For n-butyl acrylate, the in-depth litera ture search was conducted through February 2014. 24

25



## 1.3 General Substance Information 26

27

Chemical: n-Butyl acrylate 28

29

CAS No: 141-32-2 30

31

Synonyms: 2-Propenoic acid butyl ester; Acrylic acid butyl ester (8Cl); Butyl acrylate * 32

33External Review Draft

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information quality guidelines. It has not been formally di sseminated by the National Institute for Occupational

Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. Chemical category: Carboxylic acid esters † 1

2

3

4

Structural formula: 5

6

7

8

Table 1 highlights selected physiochemical properties of n-butyl acrylate relevant to IDLH conditions. Table 2 9

provides alternative exposure guidelines for n-butyl acryl ate. Table 3 summarizes the Acute Exposure Guidelines 10

Level (AEGL) values for n-butyl acrylate. 11

12

Table 1: Physiochemical Properties of n-Butyl Acrylate 13

14

Property Value

Molecular weight 128.17 ‡

Chemical formula C 7 H 12 O 2 Description Colorless liquid

Odor Strong, fruity; Rancid; Plastic

Odor Threshold 0.00096-0.10 ppm *

UEL 8% †

LEL 1.2% †

Vapor pressure 5.45 mmHg at 25°C (77°F) ‡

Flash point 28.89°C (84°F) ‡

Ignition temperature 292.78°C (559°F) ‡

Solubility Slightly soluble in water †

Abbreviation: °C – Celsius; °F – Fahrenheit; mmHg – millimeter mercury; LEL – lower explosive limit; UEL – upper explosive limit 15

‡ HSDB [2014], * AEGL [2007]; † IFA [2014] 16

17

Table 2: Alternative Exposure Gu idelines for n-Butyl Acrylate 18

19

Organization Value

Original (SCP) IDLH value None

NIOSH REL 10 ppm (55 mg/m 3 ), TWA

OSHA PEL [2014] 10 ppm (55 mg/m 3 ), TWA 8-hr

ACGIH TLV [2014] 2 ppm, TWA

AIHA ERPG [2010] ERPG-1: 0.05 ppm; ERPG-2: 25 ppm; ERPG-3: 250 ppm

AIHA WEEL [2010] Not available

Abbreviation: ACGIH – American Conference of Governmental I ndustrial Hygienists; AIHA – Am erican Industrial Hygiene 20

Association; ERPG – Emergency Re sponse Preparedness Guidelines; IDLH – immediatel y dangerous to life or health; NIOSH – Nationa l 21

Institute for Occupational Safety and Hea lth; OSHA – Occupational Safety and Health Administration; PEL – permissible exposure limit; 22

REL – recommended exposure limit; SCP – Standards Completion Program; WEEL – workplace envi ronmental exposure level 23

24 H 2 C

O CH 3 OExternal Review DraftMarch 20153This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not beenformally disseminated by the National Institute for Occupational Safety and Health. It does not represent and should not be construed to represent anyagency determination or policy.Table 3: AEGL Values for n-Butyl Acrylate12Classification 10-min 30-min 1-hour4-hour 8-hour Endpoint [reference]AEGL-1 8.3 ppm44.0 mg/m38.3 ppm44.0 mg/m38.3 ppm44.0 mg/m38.3 ppm44.0 mg/m38.3 ppm44.0 mg/m3No clinical signs with repeatedexposures [Rohm and Haas Co. 1992;Merkle and Klimisch 1983]AEGL-2 160.0 ppm850.0 mg/m3160.0 ppm850.0 mg/m3130.0 ppm690.0 mg/m381.0 ppm430.0 mg/m353.0 ppm280.0 mg/m3Clinical signs and histopathology withrepeated exposure[Klimisch et al. 1978]AEGL-3 820.0 ppm4,400.0 mg/m3820.0 ppm4,400.0 mg/m3480.0 ppm2,600.0 mg/m3170.0 ppm906.0 mg/m397.0 ppm520.0 mg/m3Calculated BMCL05from LC50data[Oberly and Tansy 1985]Abbreviation: AEGL – acute exposure guideline levels; mg/m3– milligrams per cubic meter; min – minute; NR – not recommended due to inadequate data; ppm – parts per million3*References: NAS [2007]4External Review Draft

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Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. 

## 2.0 Animal Toxicity Data 1

2

The available data on n-butyl acrylate lethality and toxicity are limited. LC 50 values were not substantially 3

different among hamsters, rats, and mice . Engelhardt and Klimisch [1983] e xposed hamsters and rats to n-butyl 4

acrylate for 6 hours/day for 4 days at concentrations of 817 and 820 ppm, respectively. Clinical signs, dyspnea, 5

disequilibrium, and bloody discharge fro m the eyes and noses were observed; no deaths occurred in rats, however, 6

four male hamsters died during the exposure period. N- butyl acrylate caused clinical signs of irritation in all 7

species tested. 8

9

The most reliable animal lethality data ca me from the Oberly and Tansy [1985] 4-hour LC 50 study in rats. Male 10

Sprague-Dawley rats were exposed whole body for 4 hours to 1,990, 2,035, 2,500, 2,828, or 3,041 ppm n-butyl 11

acrylate followed by a 14-day observation period. Vapor c oncentration was determined by gas chromatography. 12

During exposures animals had normal behavior during the firs t few minutes, then exhibited irritation of the eyes, 13

nose, and respiratory tract and labored breathing. All d eaths occurred within 24 hours and were attributed to 14

cardiopulmonary collapse. The number of deaths at each con centration was 0, 1, 3, 5, and 7, respectively. The 4- 15

hour LC 50 was calculated as 2,730 ppm. NAS [2007] calculated a 4-hour lethality BMCL 05 value (a statistical 16

lower confidence limit on the dose that produces a predetermine d change in response rate of an adverse effect) by 17

log-probit analysis using US EPA Benchmark Dose Software version 1.3.2. The resulting 4-hour BMCL 05 of 18

1,652 ppm was adjusted to a 30-minute exposure durati on concentration of 8,179 ppm. Kirkpatrick [2003] 19

measured respiratory depression in mice; the lowest e ffect level for respiratory depression was 100 ppm, the no 20

effect level was 30 ppm, and the calculated RD 50 was 340 ppm. In a 4-hour LC 50 study in rats, BASF [1979b,c; 21

1980] reported severe irritation at 677 ppm. 22

23

Table 4 summarizes the LC data identified in animal st udies and provides 30-minute equivalent derived values for 24

n-butyl acrylate. Table 5 provides non-lethal data repor ted in animal studies with 30-minute equivalent derived 25

values. Information in this table includes species of test animals, toxicological metrics (i.e., LC, NOAEL, 26

LOAEL), adjusted 30-minute concentration, and the justifi cation for the composite uncertainty factors applied to 27

calculate the derived values. 28External Review DraftMarch 20155This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not beenformally disseminated by the National Institute for Occupational Safety and Health. It does not represent and should not be construed to represent anyagency determination or policy.Table 4: Lethal Concentration Data for n-Butyl Acrylate12Reference SpeciesLC50(ppm)LC10(ppm)Time(min)Adjusted30-minConcentration*CompositeUncertaintyFactorDerivedValue(ppm)†BASF [1979a] Hamster 1,201 -- 240 5,946 30‡ 198BASF [1979a] Mouse 1,278 -- 240 6,327 30‡ 211Oberly and Tansy [1985]Rat2,730--24013,516 30‡ 451Oberly and Tansy [1985] Rat -- 1,652 240 8,179 10±818BASF [1979b,c; 1980] Rat 1,936 -- 240 9,585 30‡ 3203Abbreviation:LC – lethal concentration; LC10– concentration estimated to cause a 10% mortality rate; LC50– median lethal concentration; LCLo– lowest concentration4of a chemical that caused death in humans or animals; min – minute; ppm – parts per million5*NAS [2007] empirically estimated n = 1.3 by combining 1- and 4- hour LC50data sets from ethyl acrylate in a 3-dimensional probit analysis. The n = 1.3 was used during6all duration adjustments for n-butyl acrylate.7†The derived value is the result of the adjusted 30-minute LC value divided by the composite uncertainty factor.8‡Composite uncertainty factor to account for adjustment of LC50values to LC01values, use of lethal concentration threshold in animals, interspecies differences and9human variability.10±Composite uncertainty factor to account forlethal concentration threshold in animals,interspecies differences and human variability.11extrapolation from a threshold for escape-impairing effects in animals, animal to human differences, and human variability12External Review DraftMarch 20156This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not beenformally disseminated by the National Institute for Occupational Safety and Health. It does not represent and should not be construed to represent anyagency determination or policy.Table 5: Non-lethal Concentration Data for n-Butyl Acrylate12Reference SpeciesNOAEL(ppm)LOAEL(ppm)Time(min)Adjusted30-minConcentration*CompositeUncertaintyFactorDerivedValue(ppm)†Kirkpatrick [2003]+Mouse -- 340‡30 340 3±1133Abbreviation:NOAEL – no observed adverse effect level; min – minute; LOAEL – lowest observed adverse effect level; ppm – parts per million4*NAS [2007] empirically estimated n = 1.3 by combining 1- and 4- hour LC50data sets from ethyl acrylate in a 3-dimensional probit analysis. The n = 1.3 was used during5all duration adjustments for n-butyl acrylate.6†The derived value is the result of the adjusted 30-min value divided by the composite uncertainty factor. The composite uncertainty factor used varies for each study7based on the nature and severity of the endpoint observed.8+Identified study is the primary basis ofthe IDLH value for n-butyl acrylate.9‡This concentration was determined to be a RD50(concentration estimated to result in a 50% depression in breathing rate).10±Composite uncertainty factor to account forextrapolation from a threshold for escape-impairing effects in animals, animal to human differences, and human variability.1112External Review Draft

March 2015

7

This information is distributed solely for the purpose of pre-dissemination peer review under applicable

information quality guidelines. It has not been formally di sseminated by the National Institute for Occupational

Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. 

## 3.0 Human Data 1

2

No reports of human fatalities from exposure to n-butyl acr ylate were found. Very little information is available 3

concerning human exposure to n-butyl acrylate. Symptoms of irritation were occasionally reported in chemical 4

plant workers [Tucek et al. 2002]. Dermal sensitizatio n has been reported [BIBRA 1991], but not respiratory 5

sensitization. 6



## 4.0 Summary 7

8

In the absence of adequate human data, the IDLH value is based on animal data. Although lethality data are 9

available (see Table 4), the preferred data that serve as the basis of the IDLH value indicate respiratory 10

depression, which is categorized as an escape-impair ing effect. Kirkpatrick [2003] reported a 30-minute RD 50 11

value in mice exposed to 340 ppm. This effect is classified as potentially escape impairing. No duration 12

adjustment was needed. Application of a composite uncertainty factor of 3 to account for extrapolation from a 13

threshold for escape-impairing effects in animals, animal to human differences, and human variability yielded an 14

IDLH value of 113 ppm

. 15External Review Draft

March 2015

8

This information is distributed solely for the purpose of pre-dissemination peer review under applicable

information quality guidelines. It has not been formally di sseminated by the National Institute for Occupational

Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. 

## 5.0 References 1

2

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BASF [1979a]. Unpublished studies (78/623) . Ludwigshafen, Germany: BASF. 27

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information quality guidelines. It has not been formally di sseminated by the National Institute for Occupational

Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. [http://gestis-en.itrust.de/nxt/gateway.dll?f=templates&f n=default.htm&vid=gestiseng: sdbeng]. Date accessed: 1

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Safety and Health. It does not represent and should not be construed to represent any agency determination or

policy. 1

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