Apr-10-2009 10:12
El Toro’s Radium Contaminated Hangar ‘in Limbo’
Robert J. O'Dowd Salem-News.comHangar 296, constructed in 1944 is over 200,000 square feet in area. It is the second of two huge maintenance hangars in the highly industrialized section of El Toro.
 The now-closed El Toro Marine Corps Air Station is seriously contaminated by TCE- trichloroethylene, but problems around Hangar 296 are radioactive, and research indicates that ra-226 contaminants will be around for a long time. Salem-News.com photo by Tim King |
(IRVINE, Calif.) - A huge maintenance hangar at former MCAS El Toro remains “radiological restricted” over California Department of Public Health concerns about a Navy radiological survey.
The California Department of Public Health (CDPH) has not approved an MCAS El Toro hangar contaminated with Radium-226, despite a July 2002 Navy report recommending unrestricted use.
The Navy recommended that Hangar 296 and 297 be “radiologically released” from unrestricted use in July 2002. The Radium 226 was found only in Hangar 296. CDPH did release Hangar 297 for unrestricted use, but not its twin, Hangar 296.
Both maintenance hangars have been identified as sources of the trichloroethylene (TCE) plume spreading into Orange County’s principal aquifer. Follow-up by the Salem-News.com with CDPH indicated that the state had concerns about the Navy’s radiological survey of the hangar. CDPH did not respond to requests for additional information on the specific concerns preventing unrestricted use.
Based on an agreement with the U.S. Nuclear Regulatory Commission, CDPH “has been designated as the agency responsible for administering programs to protect the citizens of California from unnecessary exposure to radioactive materials. Although the NRC has responsibility for monitoring facilities under Federal jurisdiction, DHS becomes involved when a Federal facility, such as MCAS El Toro, is undergoing closure in a plan to revert to State control.”
Radium 226 (Ra-226) at high levels is a known human carcinogen. Navy monitoring wells on base reported elevated levels of alpha radiation from Ra-226 in groundwater confined to an area near several landfills, but there does not appear to be any risk of exposure to local residents. However, no efforts were made to contact Marine veterans who worked in the area and may have been exposed to radiation.
For some Marine veterans of El Toro, the news of Ra-226 contamination in this hangar must seem like a “double whammy.” Hangars 296 and 297 had been identified by EPA as primary sources of the trichloroethylene (TCE) plume, spreading into Orange County for over twenty years. No El Toro Marine veterans were ever notified by the Navy or Marine Corps of their possible exposure to TCE and its health effects and it appears unlikely that any veterans who worked in Hangar 296 will be informed of their possible exposure to Ra-226 and its health effects.
El Toro closed in July 1999 with much of the former base sold at a public auction in July 2005. Many El Toro veterans are now geographically dispersed throughout the country. Even if the Defense Department was required to notify these veterans, it would not be an easy task. For example, there is no database for the Navy or Marine Corps to readily identify El Toro veterans. EPA, responsible for oversight of Superfund sites like El Toro, has not even listed Ra-226 as a contaminant of concern so anyone accessing EPA’s El Toro Superfund site would be unaware of their possible exposure to Ra-226.
Hangar 296, constructed in 1944 is over 200,000 square feet in area. It is the second of two huge maintenance hangars in the highly industrialized section of El Toro. The hangar was the site of the base’s radium paint room, located in the lower north mezzanine of the building. According to the Navy, the radium paint room operated from the 1940s until the mid-1960s. Marines used radium luminescent paint on military aircraft’s instruments and gauges to allow pilots to fly at night without detection. The use of Ra-226 for this process was discontinued by the Navy and Marine Corps in the 1960s.
A radium paint room was a common feature on many military airfields. Discovered by Marie and Pierre Curie in 1893, radium salts were first mixed with zinc sulfide during WW I to make a luminous paint. The luminous paint was used on various military instruments and gauges. Alpha particles from the radium collided with zinc sulfide molecules emitting a light over the painted surface. It served as an effective means of illuminating watches and even gun sights to allow the user to view the item at night.
One major problem with Ra-226 is that it has a half-life of 1,600 years. According to McGraw-Hill’s Encyclopedia of Science and Technology, “half life is the average time interval required for one-half of any quantity of identical radioactive atoms to undergo radioactive decay.” When radium decays, it divides into two parts. Radiation is one part and the second part or daughter is like radium unstable and divides into radiation and another daughter until a stable, nonradioactive daughter is formed. During this lengthy decay process, alpha, beta, and gamma radiations are released. For example, if there were 2 grams of Ra-226 in the year 409, then 1 gram would still remain in 2009. It’s obvious that any Ra-226 contaminants will be around a long time.
Radiological Survey
Roy Weston, a Navy consultant, reported in July 2002 that engineering drawings and a base radiological assessment “showed the existence of a radium room and supporting rooms in the north mezzanine of Hangar 296. Records have been found to substantiate that refinishing of radio-luminescent dials was authorized from March 1949 to October 1950. In addition, other areas of Hangars 296 and 297 stored and used aircraft equipment containing radioactive strontium and krypton until closure in 1999.”
Based on a review of Weston’s report, the Navy contractor reported that “all areas [in the hangar] “were considered impacted and were surveyed. Impacted areas were further divided into one of three classifications:
Class 1 Areas: Areas that have, or had, a potential for radioactive contamination based on site history, or known contamination above established release limits.
Class 2 Areas: Areas that have, or had, a potential for radioactive contamination based on site history, but are not expected to exceed established release limits.
Class 3 Areas: Areas that are not expected to contain any residual radioactivity. These areas have a very low potential for residual radioactive contamination, but insufficient information exists to justify a non-impacted classification.
Roy Weston’s radiological survey results showed that most of the lower North mezzanine Hangar and a section of the upper North mezzanine (administrative work space) were classified as either Class 1 or Class 2 areas.
The Navy completed remediation activity in the hangar, including dismantling the entire portion of the ventilation system from the radium room and removing it from the area, resurfacing the hangar roof, removing plumbing system components, and removal of some floor tiles.
An unanswered question is what’s holding up the state’s approval of unrestricted use of this hangar?
