Petroleum distillates are separated from crude oil for many industrial uses. They can be found on a pesticide product label as active or "other/inert" ingredients. Mineral oil, naphtha, heavy fuel oil, waxes, and benzene are examples of petroleum distillates.

Pesticide manufacturers are not usually required to list other/inert ingredients. There are exceptions, like when a product contains more than 10% petroleum distillates. This is because of possible negative health effects.

Petroleum distillates as other/inert ingredients:

• evaporate slower than water drops, reducing drift
• allow pesticides to reach their targets better, similar to adjuvants
• reduce runoff and improve rain resistance
• may not be listed if less than 10% of the product

Petroleum distillates as active ingredients:

• are often called "horticultural oils"
• control pests physically by blocking insects' air holes
• can act as poisons and affect how insects eat

Consider these tips when choosing or using pesticides:

• A local expert with county extension may be able to help with product choices.
• The manufacturer may be able to answer questions about petroleum distillates in a product.
• Manufacturers may reveal other/inert ingredients to medical staff for treatment.
• Always follow the label.

Additional Resources:

• Insect Control: Horticultural Oils - Colorado State Extension
• Using Oils as Pesticides - Texas A&M AgriLife Extension
• Petroleum or Mineral Oils IPM Guidelines - Queensland Government
• Label Review Manual, Chapter 5: Ingredient Statement - US Environmental Protection Agency (EPA)
• Crude Oil Distillation - US Energy Information Administration (EIA)

If you have questions about this, or any pesticide-related topic, please call NPIC at 800-858-7378 (8:00am - 12:00pm PST), or email us at npic@oregonstate.edu.