An official website of the United States government.

Search Frequent Questions

Displaying 1 - 15 of 2567

How does the drinking water PAG work with EPA’s existing Safe Drinking Water Act regulations?

The drinking water PAG is non-regulatory guidance for emergency situations only. Immediately following a radiological incident, community water systems must return to compliance with the EPA’s Radionuclides Rule. Public water suppliers will be required t

At what point and what concentrations will I be told to stop drinking tap water during a radiological emergency?

State and local officials will make decisions about continued use of tap water based upon the conditions on-site during a radiological emergency. The drinking water PAG provides information they will consider.

How often are RadNet’s near-real-time air monitoring data updated on the EPA website?

Learn the refresh schedule for the EPA's RadNet near-real-time air monitors.

What units does EPA use to report laboratory analysis results (drinking water, air filter and precipitation)?

EPA reports RadNet laboratory results in US conventional units, such as the Curie (Ci).

What is background radiation? Is background radiation a risk to me and my family?

Natural background radiation is all around us. Background radiation varies from place to place and over time, depending on the amount of naturally-occurring radioactive elements in soil, water and air.

Where can I find trainings on using the 2017 PAG Manual?

For current trainings and announced webinars, please visit the Trainings section of the PAGs page on

When do states need to implement the 2017 PAG Manual?

The PAG Manual provides non-mandatory guidance for state, local and tribal governments to use at their own discretion when planning for and responding to a radiological emergency.

I’m having trouble with the CAP-88 software; who can I ask for help?

For questions and troubleshooting help with the CAP-88 software, please contact the Environmental Protection Agency.

How do I merge my population datasets from older versions of CAP-88 to CAP-88 Version 4?

The EPA recommends that you first try the Migration Utility that is a part of CAP 88-PC Version 4. When you first install Version 4, you must do two things: First, install the code, and, second, run the Migration Utility.

What authority does EPA have to set standards that protect public health and the environment at Yucca Mountain?

The Environmental Protection Agency’s authority to set site-specific standards for Yucca Mountain comes from the Energy Policy Act of 1992. 

What is the Yucca Mountain repository?

The Yucca Mountain repository is the proposed spent nuclear fuel (SNF) and high-level radioactive waste (HLW) repository where both types of radioactive waste could be disposed

Who regulates waste from nuclear power plants?

The Nuclear Regulatory Commission (NRC) has regulatory authority over storage and disposal of all commercially-generated nuclear wastes in the United States, as well as disposal of spent fuel and high-level wastes generated by the Department of Energy.

What other agencies regulate nuclear waste?

The EPA currently has the authority to regulate the Waste Isolation Pilot Plant (WIPP) which is a Department of Energy repository that permanently disposes of transuranic waste from defense programs.

What kinds of experts and equipment does the EPA’s radiation protection program have to support a radiological emergency response effort?

The EPA is a member of several interdisciplinary radiological emergency response teams. Any one of these teams can be called upon to support a radiological emergency. Some of these teams are listed here. Federal Radiological Monitoring and Assessment

Will it be safe for me to eat food or drink water from my area after a radiological emergency?

Food in sealed containers, bottled water, sealed juice, unopened soda containers and any unspoiled food in your refrigerator or freezer will be safe to eat. Use a damp towel or cloth to wipe off cans, bottles, packaged foods, counters, plates, pots and ute