The U.S. Environmental Protection Agency has imposed a record $1.4 million fine against Detroit Public Schools for failing to monitor asbestos adequately in 256 of its 263 schools.

The agency found the districts, among other things, failed to make asbestos inspections every three years as required by law. But without reports to go on, the EPA could not say whether any schools were unsafe.

In an administrative complaint filed against the district, the EPA’s Region V office in Chicago said Detroit officials reported in January that 256 of the district’s 263 buildings did not meet federal requirements.

The EPA began investigating the district in December 1998 following a parent’s complaint.

The Asbestos Hazard Emergency Response Act requires school districts to conduct asbestos inspections every three years to determine if the material has become damaged or deteriorated, and whether it poses a health risk to students and faculty.

“Our complaint is not about minor ‘paperwork’ violations, but goes to the heart of how the asbestos program is supposed to function to protect public health in schools,” EPA Regional Administrator Francis X. Lyons said in a statement.

The fine is the largest ever levied by the EPA under the Asbestos Hazard Emergency Response Act, officials said. The law allows a $5,500 fine for each building in violation.

The EPA has talked with school and city officials in Detroit, and all are working to resolve the agency’s concerns, Lyons said. The district has 30 days to appeal the fine.

Asbestos, a naturally occurring mineral, was commonly used as a fireproofing and thermal insulating material. Exposure to airborne asbestos fibers can cause people to develop asbestosis, a lung disease, or mesothelioma, a type of lung cancer, years after exposure.