(CNN) A long-awaited government study on the toxicity levels chemicals commonly used in manufacturing was made public on Wednesday, months after a White House official warned that it could be a "potential public relations nightmare."
The 800-plus-page draft report from the Agency for Toxic Substances and Disease Registry, a division of the US Department of Health and Human Services, indicates that the "minimal risk levels" for oral exposure to two chemicals known as PFOS and PFOA are lower than the threshold currently recommended by the US Environmental Protection Agency. The EPA's levels are 10 and 6.7 times higher, respectively.
These chemicals, known as polyfluoroalkyl and perfluoroalkyl substances or PFASs, have been linked to a variety of adverse health effects including liver damage, thyroid disease, decreased fertility, high cholesterol, obesity, hormone suppression and cancer.
"I think that people should be concerned about the amount of PFOA and PFOS that is in our environment," Susan M. Pinney, a professor in the Department of Environmental Health at the University of Cincinnati, wrote in an email. "These are chemicals with long half-lives," meaning they persist in the environment as well as the body.
"Exposure in utero may have the greatest effect on developing children ... and effects may last into adulthood," she said, adding that the science is still early.
Introduced more than 60 years ago, PFASs are manmade chemicals that degrade very slowly, if at all, in the environment.
The chemicals are used to make food packaging materials, such as pizza boxes and popcorn bags, fabrics, nonstick cooking pans and firefighting foams.
PFOA and PFOS are no longer manufactured or imported into the United States but were used widely until the mid-2000s. But similar "replacement chemicals for PFOA and PFOS such as GenX, may be just as persistent," Pinney said.
As a result of their ubiquity, the chemicals migrate into air, household dust, food, soil and ground and surface water, and they eventually make their way into drinking water.
Pinney said there are immediate things that can be done, including "granular activated charcoal filtration systems which will remove much (although not all) of the PFOA." She also said more research and information on the potential health effects of these chemicals and improved detection systems is needed.
The report was held up for months, and internal emails obtained in April by the science advocacy group Union of Concerned Scientists showed EPA and White House officials discussing the impact of the report. The emails said the report would show two chemicals, PFOA and PFOS, to be a danger at concentration levels allowed under current EPA guidelines. Politico first reported on the emails.
The emails became public around the time the EPA held a conference on these chemicals in water. EPA allowed a small number of reporters to attend EPA Administrator Scott Pruitt's remarks at this conference. CNN was among those excluded, and an Associated Press reporter asking to attend the meeting was shoved out of the building by a security guard.
Pruitt said at the conference that his agency would review and set limits on PFAS chemicals in water, but advocates voiced concern that the limits would not be strict enough and would put people at risk.