The U.S. Environmental Protection Agency has taken offline the datasets that underpin its flagship assessment of cancer risk from air pollution, cutting off access to the modeling tools that regulators, researchers and community groups use to gauge exposure at the facility and neighborhood level.

The affected resource is the EPA's air toxics screening work, built on the National Air Toxics Assessment (NATA) framework and its successor, the AirToxScreen assessments. These products combine emissions inventory data from industrial sources — including cement kilns, secondary metals processors, hazardous waste combustors and other combustion facilities that also sit in the waste and recycling stream — with dispersion modeling to estimate long-term cancer and respiratory risk by census tract.

With the data dark, the public cannot retrieve the tract-level risk estimates that previously allowed comparison between jurisdictions, identification of hotspots near industrial operations, and tracking of whether risk levels were rising or falling as emissions controls and plant closures changed the source landscape.

For the waste and recycling sector, the loss is concrete. AirToxScreen and NATA outputs have served as screening inputs for environmental justice analyses around landfills, kilns that burn hazardous waste, and scrap processing operations. Community groups and permit opponents have cited the assessments in comments on facility permits and in litigation. State and local air agencies have used the same data to prioritize monitoring and enforcement.

The EPA has not announced a replacement timeline for restoring public access, and it remains unclear whether the assessments will continue to be produced on their annual cycle. That uncertainty leaves a gap ahead of the next round of Clean Air Act risk reviews — including the periodic residual-risk and technology reviews for major source categories such as hazardous waste incinerators — where screening-level risk estimates have historically informed the regulatory record.

What comes next depends on whether the EPA resumes publication of the assessments and on what Congress and the agency's inspector general do in response to the disappearance of the data from the public record.