ARDEN HILLS — Work to clean up and clear what once was Minnesota’s largest contaminated Superfund site has reached a milestone. 

Ramsey County officials said the former Twin Cities Army Ammunition Plant in Arden Hills has been cleaned to standards for residential development, paving the way for the Rice Creek Commons development.

Ramsey County bought the heavily contaminated property for $28 million in 2012. The county said it is working with the state and federal pollution control agencies to certify the cleanup and remove the site from the Superfund list. Officials said 93 percent of the materials removed from the 427-acre site have been recycled or reused in new roads.

Employment at the small arms ammunition plant was at its peak in 1943 when about 26,000 people worked there. More than half were women.