(CHICAGO) Three companies have been cited by the U.S. Department of Labor’s Occupational Safety and Health Administration for exposing workers to lead during the renovation of Chicago’s Old Post Office.

OSHA inspected the post office site in August 2017 after receiving referrals from the Chicago and Illinois Departments of Public Health after both health agencies reported reported an elevated blood level for an employee performing sandblasting work, according to a statement from the federal agency.

OSHA found that American Demolition Corporation, Valor Technologies Inc. and Tecnica Environmental Services Inc. failed to comply with OSHA’s respiratory protection, provide training and properly handle personal protective equipment, according to the statement.

American Demolition was also cited for failing to establish a written lead compliance program, according to the statement.

The companies face a total of 31 citations.

Proposed penalties for American Demolition were $10,765; the penalties for Valor are $64,538; and Tecnica was penalized $50,194, according to the statement.

“It is well known that exposure to lead can cause chronic adverse health effects,” Des Plaines Area Office OSHA Director Angelina Loftus said in the statement.

“Employers must monitor lead hazards and limit employee exposure through proper respiratory use, personal protective equipment, and training,” Loftus said.

The companies have 15 business days to comply, request an informal conference with OSHA’s area director or contest the findings before the indpendent OSHA Commission.