On Oct. 28, the Nuclear Regulatory Commission cited Walmart (WMT) for improperly disposing of nuclear material. The items in question were exit signs that contained tritium, a hydrogen isotope, and Walmart had apparently been lax in its removal of 2,979 of them. The massive retailer also neglected to hire someone to keep track of its radioactive signage, in direct contravention of the NRC's requirements.

The NRC could, if it wished, levy a $369,300 fine on Walmart; however, it chose to waive the fee because the chain quickly responded to the citation. Walmart tallied the tritium-based signs at its stores, cleaned up radioactive spills created by its broken signs, and eventually decided to switch from tritium-based signs to more conventional -- and nonradioactive -- signs.
Although tritium is probably best known for its role as a neutron initiator and booster in nuclear weapons, it is used for a wide variety of civilian purposes. Its ability to glow in the dark makes it handy for firearm manufacturers, who use it in rifle sights; timepiece manufacturers often paint watch hands and numbers with the isotope for the same reason.

And, as Walmart's recent problems demonstrate, tritium can be handy for exit signs. Since they provide illumination without electricity, tritium-based signs can be placed far from electrical outlets, will continue to work when electricity shuts down, and can run for up to twenty years with minimal maintenance. Unfortunately, they also have one major downside: if they are damaged, they can release tritium gas, a radioactive pollutant that can enter the body through the lungs, open wounds, or the skin. On the bright side, tritium gas dissipates quickly in well-ventilated areas, and its tendency to leave the body quickly means that it would require exposure to large amounts to cause cancer.

Walmart isn't the only retailer getting targeted by the NRC for questionable disposal of tritium-based exit signs. Sixty other companies, including Home Depot (HD), Northwest Airlines (DAL) and Bed, Bath and Beyond (BBBY) are also facing investigation. And, lest it appear that the government is unfairly targeting commercial and industrial groups, it's worth noting that NASA, West Point, the U.S. Postal Service and dozens of other government-owned and administered facilities are also facing investigation by the NRC.

As the NRC joins the SEC and the FDA in launching new, energetic investigations, it's worth asking if the government has suddenly grown a fresh set of very sharp teeth!