AUGUSTA — State health officials are urging residents to sign up for free disposal of unusable pesticides at locations throughout the state.

The Obsolete Pesticide Collection program is aimed at family-owned farms, greenhouse owners, other business owners and even homeowners with unusable pesticides.

Unusable pesticides, such as weed killers and bug killers, can be dangerous to humans, pets and the environment. Pesticides can become unusable due to age, freezing or evaporation, or because their legal registration changes. Improper disposal of these products can contaminate land and water resources, including drinking water.

Participants must preregister by Oct 5. Drop-ins are not permitted. Collections will occur at four sites: Presque Isle, Bangor, Augusta and Portland.

To register and learn important information about the temporary storage and transportation of obsolete pesticides, go to the BPC website at thinkfirstspraylast.org or call 207-287-2731.

The program is sponsored by the Maine Department of Agriculture, Conservation and Forestry’s Board of Pesticides Control and the Maine Department of Environmental Protection. The program is funded through product registration fees; since 1982 it has kept more than 103 tons of pesticides out of the waste stream.