Unsuspecting demolition contractors and building owners disposing of self-illuminating EXIT signs containing tritium are responsible for triggering radiation alarms at landfills and causing tritium to get into landfill leachate.

At a hearing by the Senate Environmental Resources and Energy Committee on June 28, David Allard, Director of DEP’s Bureau of Radiation Protection, explained how broken EXIT signs containing tubes of radioactive tritium end up in landfills and trigger the monitors.

Frequently demolition contractors and building owners do not know they have an EXIT sign that contains radioactive materials because the special labels that include identifying information and disposal instructions have been painted over or has come off.

The EXIT signs containing tritium are the self-illuminating type that are not lighted by any other means. Contractors and building owners remodeling or disposing of these signs are required by the Nuclear Regulatory Commission to either return them to their manufacturer or treat them like low-level radioactive waste and not dispose of them in the regular trash.

Broken EXIT signs can leak tritium into a landfill and then into the leachate that is treated and released into local streams or through a municipal wastewater plant. Allard said DEP did a special two-year study that sampled water down stream from discharge points for treated landfill leachate near drinking water intakes and found no levels that threatened public health. DEP has also added tritium to the regular quarterly groundwater and discharge monitoring done by landfills.

Allard noted dilution is the primary means of dealing with any tritium concentrations in water that may be found to be a health hazard. Tritium is extremely difficult to remove from water because it is technically radioactive hydrogen.

There are an estimated 2 to 3 million EXIT signs containing tritium in the U.S..

Several Senators suggested that an education campaign is needed to teach demolition and other contractors and building owners about how to identify EXIT signs containing tritium and how to properly dispose of them.

Since 2000, over 170 landfills, municipal waste incinerators and waste transfer stations have installed radiation monitors required by DEP. Each waste truck pass through the monitors before going into the facility to detect sources of radiation.

Most often, according to Allard, the monitors are triggered by radioactive material from animals or human patients who have undergone a nuclear medicine treatment.

When the monitor is triggered, staff at the facilities are trained to identify the radiation source using a special radiation monitor. If a radiation source is above certain levels established in DEP’s rules or if it cannot be identified, DEP staff is called to the site. The vehicle is then isolated and a search is conducted through the waste to find and properly deal with the radiation source.

To watch the hearing online or to get copies of all testimony presented, visit the Senate Environmental Resources and Energy Committee webpage.

Senator Mary Jo White (R-Venango) chairs the Senate Environmental Committee along with Senator Ray Musto (D-Luzerne) who is the Minority Chairman.

7/7/2006