Colorado today has an industrial-chic vibe, with all its converted warehouses and whatnot. Until recently, though, a lot of these places were straight industrial, no chic — and the state is still wrestling with the pollutants that were left behind.

On the Front Range, Commerce City wants to build nearly 1,000 acres of homes, offices and stores on the Rocky Mountain Arsenal, according to Denver Business Journal. Because the place was fouled by decades of chemical-weapon and pesticide manufacturing, development can’t move ahead until Congress gives permission. Colorado’s U.S. senators and one representative are partnering up to try to change that, KUNC reports in a longer piece on the proposal.

In Pueblo, the Colorado Smelting Company operated its blast furnaces from 1883 to 1908. The government caught on to the possibility of contamination in the 1990s, according to the EPA, and dangerously lead-heavy dust most recently turned up in 19 homes near the smelter site, at levels nearing ten times the limit, The Pueblo Chieftain reported. The EPA still plans to test hundreds more homes.