The Postal Service™ must respond to a request from the Nuclear Regulatory Commission (NRC) on possession, transfer, and disposal of EXIT signs that contain tritium, a natural occurring radioactive gas. The NRC and various state regulatory agencies require proper recordkeeping and disposal of such signs. To comply with the request, the Postal Service is collecting information that will be based on a nationwide survey of emergency EXIT signs at each facility.
n Installation heads, postmasters, and station managers should do the following:
1. Survey their facilities to identify existing and in-stock emergency EXIT signs to determine if they are the tritium-containing type. (See “How to Identify Tritum EXIT Signs” here.)
2. If tritium-containing EXIT signs are found, use the survey form found in this article to collect the following data for each sign:
n Serial number.
n Date of manufacture.
n Manufacturer’s name.
n Location of sign.
n Condition (Are all tubes or only one or more illuminated?).
Note: Data collection applies to tritium-containing emergency EXIT signs only.
3. Submit the completed form via e-mail or fax to their servicing safety office by April 24, 2009.
n Plant safety specialists should do the following:
Send responses they receive to the district safety office (DSO).
n DSOs should do the following:
1. Follow up with offices on any apparent false positives or damaged signs.
2. Consolidate the information by district.
3. Submit it to the manager, Safety and Environmental Performance Management, at Headquarters by May 8, 2009.
Tritium-containing signs:
n Are commonly used in areas where it is difficult to install electric signs, and do not require electricity or batteries.
n Usually are less than 1 1/2 inches thick.
n Have a permanent warning label that:
n Mentions tritium (H-3), states “Caution-Radioactive Materials,” and displays the three–bladed radiation warning symbol (see sample warning symbol below).
n Is usually on the bottom or an edge, and the radiation trefoil symbol is usually visible.
n Displays the sign manufacture date and how much tritium it contains, e.g., “7 Curies.”
If the label is not observable, try extinguishing all lights in the vicinity. If the word “EXIT” is green, the light contains tritium. Each letter in EXIT is an individual tube. If all four letters of EXIT are not fully lit, the sign may be damaged and may need to be replaced.
Sample of 3-bladed radiation warning symbol
The NRC has stated that the tritium gas in these EXIT signs poses little to no risk to the health and safety of the public and does not constitute a security risk. The signs are considered inherently safe enough to be handled or used by anyone with no radiation training or experience.
For information on safe handling of tritium-containing EXIT signs, see the environmental InfoPak on Management of Tritium Containing Exit Signs, available at http://safety toolkit.usps.gov/resources/resources.aspx.
