Benzene

Benzene is a clear, sweet-smelling liquid that evaporates easily. It is a known cause of cancer, particularly leukemia, and it also damages the blood and bone marrow. It is found in gasoline, crude oil and many industrial processes. Because it’s so common in fuel, many workers are exposed without realizing it.

• General Industry
• Oil & Gas
• Mechanics

Where workers meet benzene

• Gasoline contains a small percentage of benzene. Fueling, tank work, spills, siphoning and fuel system repair expose workers.
• Refineries, petrochemical plants, chemical plants, oil and gas wells and pipelines where benzene is made, processed or comes out of the ground with crude oil. See Oil & Gas Well Sites and Refinery Turnarounds.
• Tank cleaning, tanker and railcar loading and sampling.
• Solvents, paints, glues, degreasers and cleaning products may contain traces of benzene. Modern products usually contain less, but check the label and the SDS.
• Coke ovens, steel mills, laboratories and some rubber and plastics operations.
• Tobacco smoke also contains benzene.

Health effects

• Short-term: dizziness, headache, drowsiness, confusion, nausea, irritation of the eyes, nose and throat. High exposure can cause unconsciousness and death.
• Long-term: damage to bone marrow, leading to anemia, low white blood cells and low platelets, so the body can’t fight infection or stop bleeding. Benzene causes leukemia (including acute myeloid leukemia) and is linked to other blood cancers.
• Reproductive effects: it can affect menstrual cycles and may harm a developing baby. See Reproductive Hazards.
• Benzene absorbs through the skin and the vapor is easily breathed in. Effects can show up years later, so don’t judge safety by how you feel today. See Occupational Cancer.

OSHA limits

OSHA’s benzene standard (29 CFR 1910.1028 for general industry and 1926.1128 for construction) sets:

• A permissible exposure limit (PEL) of 1 part per million (ppm) averaged over 8 hours.
• A short-term exposure limit (STEL) of 5 ppm averaged over 15 minutes.
• An action level of 0.5 ppm averaged over 8 hours. At or above it, the employer must monitor exposure and offer medical surveillance.

There are exceptions for some operations, such as certain gasoline-handling and low-benzene liquids. See Exposure Limits for how PELs and action levels work. You can’t smell benzene reliably. The odor can be noticed at levels that are above the PEL, but some people don’t smell it, and your nose adjusts, so never rely on smell.

What employers must do

• Monitor the air when exposure may be at or above the action level, and tell workers the results. See Air Sampling & Exposure Monitoring.
• Use controls first: substitute a less hazardous product, enclose the process, use local exhaust, ventilation and closed transfer systems. See Ventilation and Hierarchy of Controls.
• Set up regulated areas where exposure may exceed the limits, with signs and restricted access.
• Provide respirators when controls aren’t enough, with a program, fit testing and medical evaluation. See Respiratory Protection.
• Provide protective clothing and gloves that resist benzene, plus eye protection, and have workers change out of contaminated clothing. See Chemical-Protective Clothing.
• Offer medical surveillance at no cost to workers exposed at or above the action level for 30 or more days a year, including blood tests (a complete blood count). See Medical Surveillance Requirements.
• Train workers and label hazards as the Hazard Communication standard requires. See Hazard Communication.
• Keep exposure and medical records. See Access to Records.

What workers can do

• Read the SDS and label of every fuel, solvent and cleaner. Look for benzene in Section 3 and 8. See Safety Data Sheets.
• Avoid skin contact and don’t wash hands or tools in gasoline or solvents. Use the right gloves, since many common gloves let benzene through.
• Stay upwind when fueling or opening tanks. Don’t siphon gasoline by mouth.
• Use the equipment, ventilation and respirators provided, and keep containers closed.
• Wash up before eating, drinking or smoking, and leave contaminated clothing at work.
• Report symptoms such as easy bruising, frequent infections, fatigue or unusual bleeding, and get your blood tests as scheduled.

Fire and spills

Benzene is flammable, and its vapor is heavier than air, so it collects in low areas and can travel to an ignition source. Bond and ground transfers, keep ignition sources away and clean up spills using the SDS. See Flammable Liquids, Static, Bonding & Grounding and Spill Response.

Benzene checklist

• I know which products and processes on my job contain benzene
• Exposure has been monitored and I know the results
• Controls, ventilation and the right respirator and gloves are in use
• I avoid skin contact and never use fuel to wash up
• I get my medical tests and report symptoms

Last updated: October 4, 2026