For many years, the deadly properties of PCBs – short for polychlorinated biphenyls – were not well known. What was known was that this family of chemicals, used as a coolant in electrical transformers, made a great weed killer. Consequently, it was not unusual for Navy personnel at Pearl Harbor, after making their quarterly maintenance rounds at the transformer stations, to toss their samples of coolant fluid out the window and onto the surrounding soil in a well intentioned, if misguided, effort to keep the weeds from taking over.
In May of 1990, the Navy completed a survey of transformers that were under the custody of the Pearl Harbor Public Works Center, that unit of the Navy responsible generally for maintaining infrastructure, services and utilities. It identified 170 separate stations where PCBs were used in the coolant at one or another time. Of those 170, 20 were selected for site investigation inasmuch as there was a potential high risk for human exposure. The sites included transformer stations near schoolyards, commissaries, air raid shelters, vending machines, and residential areas.
The Environmental Protection Agency has set stringent cleanup standards for PCBs. Any furnishings, toys, or other household items contaminated with PCBs must be disposed of as hazardous waste. Indoor solid surfaces must be cleaned to no more than 10 micrograms per 100 square centimeters (about 16 square inches) – although areas where access to the public is restricted (such as in locked transformer vaults) maybe allowed to have up to 100 micrograms per 100 square centimeters. Soil must be cleaned up to where it is no more than 10 parts per million at depths greater than 10 inches below surface, and no more than 1 part per million down to 10 inches.
Against this background one can gain some idea of the extent of the cleanup job the Navy faces. For example, a wipe sample taken from a basement surface at the Camp Smith Officers’ Club, near a food storage area, showed PCBs to be present at a level of 310,000 micrograms per square centimeter – or 31,000,000 per 100 square centimeters, to use the surface area measurement cited in EPA standards. This represents contamination that is three million times the level permitted by federal regulations. A soil sample showed 2,800 parts per million PCBs, roughly 300 times the EPA’s subsurface soil cleanup standard, and 3,000 times its surface soil standard.
PCB contamination did not show up at all 20 sites included in the survey. At one site where contamination was found, however, the human exposure risk was so high that an immediate cleanup program was undertaken. That site is the Armed Services Special Education Training Society – or ASSETS -School, a private school for dyslexic and highly gifted students having a total enrollment, in grades K-12, of about 300. A transformer station lies between the schools classrooms and a combination playground-lunch area. A preliminary test showed PCBs were present in soil at the playground. More extensive tests conducted last December showed playground contamination by PCBs to be as high as 240 parts per million.
Moving at warp speed, the Navy prepared a cleanup plan and by March 1991, the playground area was excavated to depths ranging from one to three feet. The site has since been backfilled with clean soil and recovered with turf.
Volume 2, Number 6 December 1991