29 CFR 1910.1028: OSHA Benzene Standard

Regulatory citation: 29 CFR 1910.1028, Benzene

What Is the OSHA Benzene Standard?

Section 1910.1028 covers occupational exposure to benzene. It affects refineries, petrochemical plants, chemical manufacturing, bulk fuel terminals, tire manufacturing and laboratories. It sets exposure limits and requires monitoring, regulated areas, controls, respirators, medical surveillance and training.

Several activities are exempt. These include storage, transport, distribution, dispensing, sale or use of gasoline and other fuels after final discharge from bulk wholesale storage, oil and gas drilling, production and servicing, coke oven batteries, and mixtures with 0.1% benzene or less. Containers and pipelines are also exempt while they remain intact.

Why Benzene Matters

Benzene damages the blood-forming system and is a known human carcinogen linked to leukemia. Because effects show up in blood counts, the standard relies heavily on blood testing.

Core Obligations

1. Keep Exposure Below the Limits (1910.1028(b) and (c))

The permissible exposure limit (PEL) is 1 part per million (ppm) as an 8-hour time-weighted average (TWA). The short-term exposure limit (STEL) is 5 ppm over any 15-minute period. The action level is 0.5 ppm as an 8-hour TWA.

2. Set Up Regulated Areas (1910.1028(d))

Regulated areas are required wherever benzene levels exceed, or can reasonably be expected to exceed, the PEL or STEL. Access is limited to authorized persons, and boundaries are set to keep the number of exposed employees low.

3. Monitor Exposure (1910.1028(e))

Exposure is measured with breathing zone samples. Where exposure is at or above the action level but at or below the PEL, monitoring is repeated at least annually. Above the PEL, it is repeated at least every 6 months. Monitoring can be reduced or stopped after two consecutive results, at least 7 days apart, fall below the relevant level. Additional monitoring is needed after process changes and after spills or leaks. Employees must be told their results within 15 working days.

4. Use Controls and a Written Program (1910.1028(f))

Engineering and work practice controls must be used first to meet the limits. Where exposure is above the PEL, a written compliance program with a schedule for controls is required. Where benzene is used fewer than 30 days a year, respirators or other controls may be used to meet the PELs, but engineering and work practice controls must still be used to reduce exposure to 10 ppm as an 8-hour TWA where feasible.

5. Provide Respirators and Protective Clothing (1910.1028(g) and (h))

Respirators are required while controls are installed, where controls are not feasible or not enough, and in emergencies. They must be used under a program meeting 29 CFR 1910.134. Air-purifying cartridges and canisters must be replaced at the end of their service life or at the start of each shift, whichever comes first. Protective clothing must be provided at no cost to prevent eye contact and limit skin contact with liquid benzene.

6. Provide Medical Surveillance (1910.1028(i))

Medical surveillance covers employees exposed at or above the action level 30 or more days a year, or at or above the PEL 10 or more days a year. It also covers tire building machine operators using solvents with more than 0.1% benzene. The initial exam includes a work and medical history, a physical exam and a complete blood count (CBC), with periodic exams annually. Persistent abnormal blood results require referral to a hematologist or internist, and an employee removed from exposure keeps wages, seniority and benefits for up to 6 months.

7. Communicate Hazards, Train and Keep Records (1910.1028(j) and (k))

Hazard communication rules apply to benzene, and regulated area signs must state that benzene may cause cancer. Training is required at initial assignment and annually for employees exposed above the action level. Exposure records must be kept for at least 30 years, and medical records for the duration of employment plus 30 years.

Common Compliance Approaches

Map Benzene Sources

List tanks, sample points, loading racks and maintenance tasks where benzene can be released, and match each to a sampling and control plan.

Treat Line Breaks as High-Exposure Tasks

Opening lines, changing filters and taking samples cause short peaks that can exceed the STEL even when 8-hour averages are low.

Example: Benzene Controls in Practice

A chemical plant samples operators who draw product samples from a benzene line. The 8-hour results are 0.3 ppm, but 15-minute samples during sampling reach 7 ppm, above the STEL. The plant installs closed-loop sample stations, sets up a regulated area around the sample point and requires respirators until follow-up sampling shows the STEL is met. Operators with enough exposure days are placed in the medical program with annual blood counts.

Related regulations: OSHA Process Safety Management, OSHA respiratory protection, OSHA access to exposure and medical records.

Note: In July 2025 OSHA proposed changes to the respirator provisions of this standard. OSHA reopened the comment period in July 2026 and held public hearings in August 2026. No final rule had been issued as of October 2026, so check for updates. State plan states may set stricter rules.

Frequently Asked Questions

Does the benzene standard cover gas stations?

Generally no. Fuel handling after final discharge from bulk wholesale storage is exempt, except for indoor gasoline dispensing for more than 4 hours a day.

What triggers medical surveillance?

Exposure at or above the action level for 30 or more days a year, exposure at or above the PEL for 10 or more days a year, or work as a tire building machine operator using solvents with more than 0.1% benzene.

How often must benzene exposure be monitored?

At least annually for results at or above the action level and at or below the PEL, and at least every 6 months for results above the PEL.