Used Engine Oil

Why am I being warned about potential exposure to used engine oil?

Used engine oil contains chemicals such as benzo[a]pyrene and other polycyclic aromatic hydrocarbons (PAHs), which are on the Proposition 65 list because they can cause cancer.
Used mineral-based engine oil is on the Proposition 65 list under the entry for “soot, tars, and mineral oils (untreated and mildly treated oils and used engine oils)” because it can cause cancer.
Exposure to used engine oil may increase the risk of cancer.
Proposition 65 requires businesses to determine if they must provide a warning about significant exposure to listed chemicals.

What is used engine oil?

It is oil that has been used to lubricate various parts of an internal combustion engine, such as the crankcase, gears, or transmission. Used engine oil is also commonly referred to as used motor oil.
Mineral-based engine oil is made with base oils from petroleum. Synthetic engine oil is usually made without base oils from petroleum. Both synthetic and mineral-based used engine oils contain carcinogenic PAHs.

How does exposure to used engine oil occur?

You can be exposed to used engine oil by:
- Touching it, for example, when replacing engine oil, or handling a used engine oil filter. Some chemicals in used engine oil can be absorbed through the skin.
- Breathing in chemicals that are released into the air from used engine oil.
During pregnancy, some listed chemicals in used engine oil can pass from mother to baby.

Main ways you can be exposed to listed chemicals in used engine oil:

How can I reduce my exposure to used engine oil?

If you are changing used engine oil, try not to do so in an enclosed space. Wear gloves and safely dispose of the oil and filter.
- Used engine oil is a hazardous waste. Do not dump it in a storm drain, sewer, septic tank, or on the ground. Do not put the used oil or oil filter in regular household trash.
- Take these items to a designated used oil collection center or inquire about used engine oil collection kits and curbside pickup. If properly handled, most used engine oil can be recycled.
After handling used engine oil, wash your hands, especially before preparing food, and before eating.

For more information:

General Fact Sheets and Resources

Scientific Information on Used Engine Oil

World Health Organization (WHO)
International Agency for Research on Cancer (IARC)
- “Mineral Oils, Untreated or Mildly Treated” section in Chemical Agents and Related Occupations (2012), vol. 100F, pages 179-196.
US Department of Health and Human Services (HHS)
Agency for Toxic Substances and Disease Registry (ATSDR)
- Public Health Statement for Used Mineral-Based Crankcase Oil

Proposition 65

California Environmental Protection Agency (CalEPA)
Office of Environmental Health Hazard Assessment (OEHHA)
- Proposition 65: Background
- Proposition 65: The List of Chemicals
- Proposition 65: Fact Sheets