The U.S. Environmental Protection Agency (EPA) knows that dozens of the chemicals used in fracking pose health hazards. The agency not only allows their use, but also lets the oil and gas industry keep the chemicals secret, according to a new report.

Between 2003 and 2014 the EPA identified health hazards for 41 chemicals used in fracking, according to a report from the Partnership for Policy Integrity and Earthworks, based on documents obtained through a Freedom of Information Act request. Fracking is the injection of a chemical slurry into drilling sites to free up underground oil and gas deposits. Hazards from the chemicals used included irritation to eyes and skin; harm to the liver, kidney and nervous system; and damage to the developing fetus.

Nonetheless, in most cases, the EPA allowed the chemicals to be manufactured and used without further testing. What’s more, the identities of the chemicals are hidden from the public, even though federal law authorizes the EPA to require disclosure of so-called trade secrets if there is unreasonable risk of injury to health or the environment.

In response to the report, more than 100 scientists, health professionals and first responders wrote the EPA, asking that it make public the identities of the chemicals known to pose health hazards.

“Citizens have a right to know what health hazards we are being exposed to, especially when these hazards have been identified by government health assessments … It is an unreasonable risk for people to be unknowingly exposed to chemicals that EPA, itself, has identified as potentially harmful,” said the letter. Signers included Sandra Steingraber, author of Living Downstream and other acclaimed books on environmental health, and Wilma Subra, winner of a MacArthur “genius” award for her work to help vulnerable communities document the health risks of industrial pollution.