General Industry (29 CFR 1910)

Acrylonitrile

Verified vs OSHA sources · 2026-10-05

29 CFR 1910.1045

29 CFR 1910.1045 protects general-industry workers from acrylonitrile (AN, or vinyl cyanide), a carcinogen used to make acrylic fibers, ABS and SAN plastics, and nitrile rubber. It caps exposure at 2 ppm as an 8-hour TWA with a 10 ppm 15-minute ceiling and a 1 ppm action level, requiring monitoring, controls, regulated areas, and medical surveillance.

29 CFR 1910.1045 at a glance

PEL: 2 ppm as an 8-hour TWA (29 CFR 1910.1045(c)(1))
Ceiling: 10 ppm over any 15-minute period (1910.1045(c)(2))
Action level: 1 ppm (8-hr TWA): triggers monitoring and medical surveillance
Health effect: Carcinogen; acutely toxic (can release cyanide in the body)
Max penalty (2026): $16,550 per serious violation; $165,514 per willful
The #1 confusion: Acrylonitrile has a ceiling, not a STEL: it must never be exceeded over any 15 minutes

What 29 CFR 1910.1045 requires (plain English)

29 CFR 1910.1045 protects general-industry workers from acrylonitrile (AN, also called vinyl cyanide): a volatile, flammable liquid used to manufacture acrylic and modacrylic fibers, ABS and SAN plastics, nitrile rubber, and acrylamide. It is a carcinogen and is acutely toxic, capable of releasing cyanide as it is metabolized.

The standard sets a permissible exposure limit of 2 ppm as an 8-hour time-weighted average and a ceiling of 10 ppm that may not be exceeded over any 15-minute period, with an action level of 1 ppm that triggers monitoring and medical surveillance. Where exposures exceed the limits, engineering and work-practice controls (closed systems, ventilation) are the primary means of compliance, with regulated areas, respirators, protective equipment, and training added.

1910.1045 is a Subpart Z substance-specific health standard. Because AN is handled in large volumes in fiber and plastics plants and is both a carcinogen and an acute poison, the standard combines a long-term PEL, a short-term ceiling, and comprehensive monitoring and surveillance.

The regulatory text

“The employer shall assure that no employee is exposed to an airborne concentration of acrylonitrile in excess of two (2) parts acrylonitrile per million parts of air (2 ppm) as an eight (8)-hour time-weighted average.”

29 CFR 1910.1045(c)(1)

Key facts about 29 CFR 1910.1045

The acrylonitrile PEL is 2 ppm as an 8-hour TWA (1910.1045(c)(1)).
A ceiling limit caps exposure at 10 ppm over any 15-minute period (1910.1045(c)(2)).
The action level is 1 ppm (8-hr TWA) and triggers monitoring and medical surveillance.
Acrylonitrile (vinyl cyanide) is a carcinogen and acutely toxic: it can release cyanide.
It is used to make acrylic fibers, ABS and SAN plastics, and nitrile rubber.
Engineering controls (closed systems, ventilation) are the primary means of compliance.
The short-term limit is a ceiling, not a STEL: it must not be exceeded over any 15 minutes.

Scope: who 29 CFR 1910.1045 applies to

Regulatory framework: General Industry (29 CFR 1910)
Citation reference: 29 CFR 1910.1045
Enforcement status: In force and enforced
Jurisdiction: Federal OSHA (29 State-Plan jurisdictions may be stricter)

State-Plan states (e.g. California, Washington, Michigan) operate OSHA-approved programs that must be at least as effective as federal OSHA and frequently impose higher penalties or additional requirements. Confirm the rule as adopted in your state.

Key requirements of 29 CFR 1910.1045

#	Employer obligation
1	Limit exposure to 2 ppm PEL
2	Ceiling of 10 ppm (15-minute)
3	Monitor exposure above action level (1 ppm)
4	Provide medical surveillance
5	Establish regulated areas above PEL

Summarized from the text of 29 CFR 1910.1045. Always read the full regulation for the binding language.

Common Acrylonitrile violations

Deficiencies OSHA cites under 29 CFR 1910.1045 include the ones below, in no particular order. Distinct deficiencies can be cited as separate items, and each serious item carries up to $16,550 (2026). Broader per-instance stacking exists but is a discretionary, case-by-case OSHA enforcement policy, not an automatic multiplier.

No exposure monitoring in acrylonitrile production or polymer operations (1910.1045(e)).
Exposures above the PEL or ceiling without adequate controls (1910.1045(g)).
No medical surveillance for workers at or above the action level (1910.1045(n)).
No regulated area where exposure exceeds the PEL or ceiling (1910.1045(f)).
Reliance on respirators instead of closed systems and ventilation (1910.1045(g)).

Acrylonitrile has a ceiling, not a STEL: the 15-minute value must never be exceeded

The short-term limit for acrylonitrile is a ceiling of 10 ppm, not a short-term exposure limit (STEL). The distinction matters: a STEL is a 15-minute time-weighted average that may be reached a limited number of times a day, but a ceiling represents a concentration that must not be exceeded at any point, evaluated over a 15-minute period. Treating the acrylonitrile ceiling like a STEL, averaging brief spikes against lower readings, understates real exposure. Combined with the 2 ppm 8-hour PEL, the ceiling is meant to catch the short, high peaks that occur during transfers, sampling, and upsets, which is where much of the acute and carcinogenic risk lies.

What OSHA inspectors look for

A compliance officer checks exposure monitoring in acrylonitrile production and polymer operations, verifies engineering controls and regulated areas where the PEL or ceiling is exceeded, and confirms medical surveillance above the action level. Reliance on respirators instead of closed systems is a common finding.

Example: how a violation is cited

Workers at an acrylic-fiber plant are exposed to acrylonitrile from an open transfer and leaking seals, above the ceiling, with no monitoring. OSHA cites 1910.1045 for the overexposure and missing surveillance, with penalties from $16,550.

Illustrative example, not a specific OSHA case.

Acrylonitrile compliance checklist

Use this to evaluate your compliance with 29 CFR 1910.1045. Each item is a key requirement OSHA may verify during an inspection.

Monitor exposures in production, polymerization, and transfer and sampling areas.
Reduce exposure to the 2 ppm PEL and 10 ppm ceiling with closed systems and ventilation.
Provide medical surveillance for workers at or above the 1 ppm action level.
Establish regulated areas where exposure exceeds the limits.
Provide respirators and impervious PPE where controls are insufficient, and plan for the acute cyanide-type hazard.
Train workers on the carcinogenic and acute (cyanide) hazards and on ceiling control.

2026 penalties for 29 CFR 1910.1045

Maximums set by 29 CFR 1903.15(d). 2026 amounts unchanged from 2025 (no CPI adjustment; OMB M-26-11). Not an increase. The 2025 OSHA penalty levels remain in effect for 2026; OSHA made no inflation adjustment for 2026. 29 CFR 1903.15 identifies January 15, 2025 as the effective reference for these amounts, while OSHA's public penalties page currently references penalties assessed after Jan. 15, 2026.

Violation type	Minimum	Maximum	When it applies
Serious	$1,085	$16,550	Substantial probability of death or serious physical harm.
Other-Than-Serious	$0	$16,550	Relates to safety/health but unlikely to cause death or serious harm.
Willful	$11,823	$165,514	Intentional, knowing, or voluntary disregard of the requirement.
Repeated	$4,256	$165,514	A substantially similar violation cited within the last 5 years.
Failure to Abate	None	$16,550/day	up to $16,550 per day; total capped at 30x the daily amount (FOM Ch.6)

Acrylonitrile citations follow health inspections of fiber, plastics, and rubber operations. Serious violations reach $16,550 and willful or repeat violations $165,514; overexposure above the ceiling without controls is the usual finding.

Maximums and the willful minimum are set by 29 CFR 1903.15(d); the serious and repeated minimums are OSHA policy floors from its annual penalty adjustment memo. OSHA applies gravity-based and size, good-faith and history reductions (FOM CPL 02-00-164 Ch.6). Estimates only, not legal advice.

The business case for Acrylonitrile compliance

Acrylonitrile is a carcinogen and an acutely toxic chemical, it can release cyanide in the body, used in large volumes to make acrylic fibers, plastics, and rubber. Keeping exposure under the 2 ppm PEL and 10 ppm ceiling with closed systems and monitoring is what protects the fiber and plastics workforce from both cancer and acute poisoning.

Free compliance tools for 29 CFR 1910.1045

SDS Gap Analyzer Respiratory Protection Program Builder PPE Selector

Acrylonitrile penalties by state

Penalties and enforcement vary by state. State-Plan states may impose higher penalties and additional requirements beyond federal 29 CFR 1910.1045.

Alabama Arkansas Colorado Connecticut Delaware District of Columbia

View all 50 states + DC →

Frequently asked questions about 29 CFR 1910.1045

What is the OSHA acrylonitrile PEL?

Under 1910.1045(c), the permissible exposure limit for acrylonitrile is 2 ppm as an 8-hour time-weighted average, with a ceiling of 10 ppm that may not be exceeded over any 15-minute period. An action level of 1 ppm (8-hour TWA) triggers exposure monitoring and medical surveillance.

Is acrylonitrile a cyanide hazard?

Acrylonitrile is also called vinyl cyanide, and it is acutely toxic partly because it can release cyanide as the body metabolizes it, in addition to being a carcinogen. Symptoms of acute overexposure can resemble cyanide poisoning. That dual hazard, chronic cancer risk plus acute toxicity, is why 1910.1045 pairs an 8-hour PEL with a strict 15-minute ceiling and requires medical surveillance.

What is the difference between the acrylonitrile ceiling and a STEL?

The 10 ppm value is a ceiling, meaning exposure must not exceed it at any time (evaluated over 15 minutes), whereas a STEL is a 15-minute average that may be reached a limited number of times per day. The ceiling is stricter about short peaks, which is appropriate for a chemical that is both carcinogenic and acutely toxic. Averaging spikes against low readings, as one might with a STEL, would understate acrylonitrile exposure.

Where are workers exposed to acrylonitrile?

Mainly in chemical plants that produce acrylonitrile and facilities that use it to make acrylic and modacrylic fibers, ABS and SAN plastics, nitrile rubber, and acrylamide. Exposure is highest during transfers, sampling, maintenance, and upsets. 1910.1045 applies wherever acrylonitrile is used and workers can be exposed above the action level.

Regulatory history of 29 CFR 1910.1045

OSHA issued the acrylonitrile standard in 1978 (43 FR 45762) after evidence linked it to cancer in exposed workers, setting the 2 ppm PEL and 10 ppm ceiling with monitoring, regulated areas, and medical surveillance. It protects the acrylic-fiber, plastics, and nitrile-rubber workforce.

Related glossary terms

Key terms that appear in 29 CFR 1910.1045, each with a full plain-English explainer.

Permissible Exposure Limit (PEL)Action Level Medical Surveillance Engineering Controls Respiratory Protection Program IDLH

Related guides & articles

Workplace Chemical Exposure Limits: PEL vs TLV OSHA Chemical Storage Requirements Complete Guide

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29 CFR 1910.1000

Air Contaminants / PELs

29 CFR 1910.1001

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29 CFR 1910.1003

OSHA 13 Carcinogens

29 CFR 1910.1018

Inorganic Arsenic

Primary sources

OSHA figures on this page are imported from HazComFast's verified regulatory module (verified 2026-10-05 against eCFR, OSHA.gov, and the Federal Register).

This page is an educational summary, not legal advice. OSHA standards and penalty amounts change; confirm requirements against the current regulation and your applicable State-Plan before acting.

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OSHA does not give advance notice of inspections (29 CFR 1903.6). Get the binder in order before the opening conference, not during it.

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