Subpart T: Disposal of Uranium Mill Tailings
Subpart T protects people and the environment from radon-222 emissions from uranium mill tailings piles that are no longer operational. The radon-222 emission rate from a uranium mill tailings pile to the surrounding (ambient) air must not exceed 20 pico curies per square meter per second. As with Subpart I, Subpart T does not apply to Nuclear Regulatory Licensees, because they are covered by NRC's regulatory system.
Releases occur both during and following the processing of uranium ores and originate from residual radioactive material and the disposal of uranium mill tailings. The Department of Energy controls 24 abandoned uranium mill tailings piles.
The original deadline for bringing uranium mill tailings piles into compliance with the standard was December 15, 1991. EPA establishes compliance agreements with owners or operators of uranium mill tailings piles that were not in compliance by that date to assure that they are disposed of as quickly as possible.
Owner operators must conduct emissions tests on piles they have sealed to prevent the escape of the radon gas and notify EPA of both what they have done and the results of the emissions tests.
In addition, there are general requirements that all facilities subject to any NESHAP must meet, 40CFR61, Subpart A: General Provisions .