The U.S. Environmental Protection Agency is seeking proposals from small business to clean up abandoned uranium mines on the Navajo Nation and in northwestern New Mexico.

About 140 people attended a workshop held this week in Window Rock to learn more about the $220 million project.

The EPA expects to award multiple contracts to businesses with less than 750 employees.

The funding comes from a roughly $1 billion settlement with the successor of a company that mined the region. Companies extracted nearly 30 million tons of uranium for Cold War weaponry.

The EPA says it has funding to assess and clean up about 220 of the more than 520 abandoned mines.

Contract proposals are due May 28 for work on the reservation and around Grants, New Mexico.