Announcements

Public Comment Period Extension

EPA has extended the public comment period for the Explanation of Significant Differences to accept comments through October 15. 

EPA is proposing to lower lead cleanup levels for soil and indoor dust at residential properties. In October 2025, EPA lowered screening levels for lead at residential Superfund sites nationwide. The Colorado Smelter site team evaluated the current residential cleanup levels based on this directive. EPA’s proposed revised cleanup levels are listed in the Explanation of Significant Differences (pdf) (1.2 MB). EPA is requesting feedback on this proposed cleanup level change for lead. We encourage all residents and interested parties to read the document thoroughly and participate in the comment period. Written comments will be accepted from September 1 to October 15.

Please submit comments one of the following ways:

• Via email: chan.sydney@epa.gov
• Via hard copy mail:  
  • Sydney Chan, EPA, SEM-RB-A
    1595 Wynkoop Street
    Denver, CO 80202

• Read more in the Engineer Evaluation and Cost Analysis document (pdf) (4.4 MB). This comment period closed on September 26. Comments will be addressed in the finalization of the EE/CA