Jump to main content.

Radiation Protection Basics
Understanding Radiation:  

Radiation Symbols

Radiation Protection Basics
Tri-Foils Symbol

The the "tri-foil" is the international symbol for radiation. The symbol can be magenta or black, on a yellow background. This sign is posted where radioactive materials are handled, or where radiation-producing equipment is used. This sign is used as a warning to protect people from being exposed to radioactivity.

This symbol is used with other messages that describe the nature of the radiation hazard, as shown below. They are displayed at locations such as, radioactively contaminated sites during the clean-up process, the nuclear medicine area of a hospital, or in university or commercial research facilities.

Caution Radiation Area Sign
Danger High Radiation Sign
Caution Radioactive Materials Sign

Fallout Shelter Sign

Fallout Shelter Sign

This sign shows the symbol for a fallout shelter. Although the designs are similar, the fallout symbol a slight variation of the radiation symbol.

Fallout shelters were principally the work of the Defense Civil Preparedness Agency, in conjunction with state and local officials. The shelters were part of a comprehensive program created to prepare U.S. citizens in the event of a nuclear attack.

The Federal Emergency Management Agency took over the Defense Civil Preparedness Agency responsibilities in 1979 (along with a few other Federal agencies). FEMA is still involved in disaster and emergency response along with state and local governments, and other federal agencies include the Environmental Protection Agency (EPA). For more information on EPA's role, visit the radiological emergency response pages.


For more information about the radiation symbol and fallout shelter image, read an article by Paul Frame, Ph.D., CHP, on the University of Michigan's Radiation and Health Physics Page. Exit EPA Disclaimer

United Nations Symbol

UN Radiation Symbol

In February of 2007, the United Nations introduced a new symbol to help reduce accidental exposure to large radioactive sources. The new icon is aimed at alerting anyone, anywhere to the potential dangers of being close to a large source of ionizing radiation.

The new symbol will not be visible under normal use, but only if someone attempts to disassemble a device that is a source of dangerous radiation. It will not be located on building access doors, transportation packages or containers.

The new symbol is the result of a 5-year project conducted in 11 countries around the world. It was developed by human factor experts, graphic artists, radiation protection experts, and tested on a total of 1,650 individuals in Brazil, Mexico, Morocco, Kenya, Saudi Arabia, China, India, Thailand, Poland, Ukraine the United States to ensure that its message of danger - "stay away" was crystal clear & understood by all.
(Source United Nations New Center article, accessed 03/08/07 Exit EPA Disclaimer)


Local Navigation

Radiation Home

Jump to main content.