The U.S. Environmental Protection Agency on Wednesday said the air in a swath of Chicago’s Southwest Side does not meet federal standards for lead. The finding is preliminary, but could lead to a crackdown on a copper smelter.

The finding supports an Illinois determination that the air in an area of the city’s Pilsen neighborhood exceeds 2008 federal limits for lead. The area’s borders are Damen Avenue, Roosevelt Road and the Dan Ryan and Stevenson expressways.

Cheryl Newton, who directs the air division of an EPA region that includes Illinois, says the process could lead to a state plan “to make sure those elevated levels come down.”

A cleanup could be a problem for a Pilsen smelter owned by H. Kramer and Co. In April a U.S. EPA legal complaint accused Kramer of violating lead-emissions rules. Illinois regulators, meanwhile, asked the state attorney general to take action.

A Kramer spokeswoman said the company had no comment on the U.S. EPA’s preliminary finding.

Pilsen and an area near St. Louis are the only Illinois locations whose air, according to the state, does not meet the standards for lead. Early childhood exposure to lead, a heavy metal, can trigger learning disabilities.