Radiation Protection

Subpart K: National Emission Standards for Radionuclide Emissions From Elemental Phosphorus Plants

Rule Summary

Subpart K protects the public and the environment from the hazards of emissions of polonium-210 and lead-210 to the ambient airHelpambient airThe air that surrounds us from phosphorus plants. The standard limits annual air emissions of polonium-210 to two curies of polonium-210 for certain processes. The standard focuses on polonium-210 because control measures that limit polonium-210 also limit emissions of lead-210.  

Elemental phosphorus plants extract pure phosphorus from ore for use in the chemical industry. Phosphate ore has a large concentration of uranium and its decay productsHelpdecay productsThe atoms formed and the energy and particles emitted as radioactive material decays to reach a stable form.. These decay products, especially polonium-210 and lead-210, become airborne through volatilization during the extraction process and could potentially enter the atmosphere in large concentrations. Exposure comes from inhaling the radionuclides, with the lungs receiving virtually all of the dose, causing an increased risk of lung cancer.

Except under certain conditions, owners or operators must test emissions annually and submit the results to EPA.


Compliance may be demonstrated if total polonium-210 emissions from the plant do not exceed 4.5 curies per year when certain scrubbing equipment is used.

All facilities subject to any NESHAP must meet 40 CFR Part 61, Subpart A: General Provisions.