More than 2,000 animal feeding operations (AFOs) have signed agreements to participate in the Environmental Protection Agency's (EPA) air compliance initiative.

Many operations that signed up have several farms that will come under the agreement, says EPA.

Applicants hail from 37 states and represent pork, egg layers, meat birds and dairy industries.

By signing up, farms commit to air monitoring and taking steps to comply with clean air standards. In return, EPA will not sue AFOs for certain violations of the Clean Air Act.

The two-year monitoring study is set to start in early 2006.