EPA issues Explanation of Significant Differences-August 2017: 
EPA  issued an ESD for the cleanup plan for the contaminated soils, or Operable Unit 3, at the Site. The ESD modifies the Early-Interim Record of Decision from June 2016 to excavate additional radionuclide-contaminated soil and debris.

The 10-acre Safety Light Corporation (SLC) site is located in South Centre Township near Bloomsburg, Pennsylvania. Past activities at the Site include the manufacturing of self-illuminated watches and instrument dials, smoke detectors, neutron sources, exit signs and other merchandise containing radioactive materials, as well as activities regulated by the U. S. Nuclear Regulatory Commission (NRC). Wastes generated at the Site include solid and liquid waste streams contaminated with radioactive materials, such as radium-226, strontium-90, cesium-137 and tritium.

The Site cleanup is divided into three separate units called Operable Units (OUs). OU-1 addresses on-site buildings and debris; OU-2 addresses on-site groundwater; and OU-3 addresses on-site soils, surface water and sediment.

From the 1940s to the 1960s, product manufacturing at the Site involved using several radioactive materials such as radium.  The facility was once owned by the U.S. Radium company.  After 1980, exit signs were the main products manufactured at the Site, which involved using tritium.

In 1981, the NRC conducted an environmental survey of the Site property; during which monitoring wells were found to contain elevated levels of tritium and strontium-90. Elevated levels of radium-226, cesium-137 and strontium-90 were also found in surface and sub-surface soils. The NRC required Safety Light Corp. to begin remediating radiological waste disposed in the two underground silos.

The NRC requested the United States Environmental Protection Agency’s (EPA's) assistance for the cleanup of the property because Safety Light Corp. had insufficient funds to complete this remediation project and proceed with any other cleanup actions.

In 2005, EPA added the Safety Light Corp. Site to the National Priorities List (NPL) making it eligible for federal cleanup funds under the Superfund program.