Quenching steel with engine oil is a practice that should be avoided due to significant health, safety, and environmental risks. While it may seem like a convenient and cost-effective option, the repercussions far outweigh the benefits.
Engine oil is a complex blend of hydrocarbons, additives, and contaminants. When heated during the quenching process, it releases a variety of harmful fumes, including:
- Benzene: A known carcinogen, long-term exposure to benzene can lead to blood disorders such as anemia and even increase the risk of leukemia.
- Formaldehyde: Classified as a carcinogen, it poses risks of respiratory issues and skin irritation.
- Polycyclic Aromatic Hydrocarbons (PAHs): These compounds are linked to skin, lung, and other cancers upon long-term exposure.
- Acetaldehyde: A probable carcinogen, it can cause eye and skin irritation.
- Acrolein: Known for causing respiratory issues, it may also contribute to heart disease.
- Carbon Monoxide: An odorless gas that can cause headaches, dizziness, and in extreme cases, can be fatal.
The health implications of exposure to these chemicals range from immediate symptoms like headaches and respiratory irritation to long-term risks such as cancer and neurological damage. The fumes can be especially harmful in a closed environment, posing severe health risks to the bladesmith.
If you cannot use commercial oil quenchants Canola and Mineral oil are better and safer options.
I cannot think of any reasons to be quenching steel with engine oil, and there are many reasons not to.