The EPA on Monday finalized a rule banning the importation and all remaining uses of chrysotile asbestos, an action officials said has been necessary for decades due to the health effects associated with the toxic mineral.

The mineral has been long linked to lung cancer and mesothelioma, and while its use has waned, EPA Administrator Michael S. Regan said on a call with reporters that the action “is finally slamming the door on a chemical so dangerous that it has been banned in over 50 countries.”

“Because of its resistance to heat, fire and electrical conduction, it has remained in use for a variety of construction and industrial products,” Regan said. “But the science is clear and settled — there is simply no safe level of exposure to asbestos.”

Chrysotile asbestos is the only form known to be imported, processed or distributed in the United States.

The EPA first finalized a ban on asbestos in 1989 under the Toxic Substances Control Act, however much of that rule was struck down by the U.S. Court of Appeals for the Fifth Circuit. The inability to ban asbestos became symbolic of the inadequacies of TSCA and was one reason Congress passed amendments to the law in 2016 (PL 114-182) to enhance the EPA’s authority.

Regan said this new rule is the first issued under the process for evaluating and addressing the safety of existing chemicals as established by the 2016 amendments.

In the years since the first attempted ban, public awareness of the dangers of asbestos caused construction material manufacturers to shift course; domestic asbestos mining ended in 2002.

However, it is still used to produce sodium hydroxide and chlorine, a critical use to disinfect drinking water and wastewater, and to fabricate braking systems and sheet gaskets, which are used to create seals for piping and other machinery.

The rule will ban most sheet gaskets containing asbestos within two years, while allowing more time for those used in facilities processing nuclear materials. The use of asbestos in braking systems will be banned within six months.

The EPA will provide five years for facilities using asbestos diaphragms to manufacture chlorine and sodium hydroxide to switch to other diaphragms, and a staggered timeline for companies that want to switch to different technologies. After the rule was proposed in 2022, some industry groups expressed concern that a ban on asbestos could impact the operation of drinking water utilities.

Michal Freedhoff, assistant administrator of the Office of Chemical Safety and Pollution Prevention, told reporters that the agency built in extra time for the conversion of these facilities to ensure the utilities will have the chemicals they need.