PCBs in Malibu Schools: How Risky are They?

There have been many recent press accounts regarding the discovery of PCBs (polychlorinated biphenyls) in certain building materials in Malibu California schools.  The Santa Monica-Malibu Unified School District (SMMUSD) retained Environ, an environmental firm, to serve as their consultant to evaluate the PCBs’ significance.  Environ tested indoor air samples, caulk samples and building material wipe samples for PCBs; based on the test results they developed an EPA approved plan for managing the PCBs in place.  But does this approach do enough to make the schools safe?

The Air Sampling Results

PCBs in school air are the primary health concern because all students and staff are breathing the air and would be exposed to PCBs if they were present.  Results of indoor air testing at the Malibu High School and at the Juan Cabrillo Elementary School show concentrations to be less than USEPA’s Public Health Values.  These levels are hundreds of time less than would be required to produce health effects.  Thus indoor air PCB concentration do not pose risk.

Wipe Sample Test Results

A secondary health concern is the potential for direct contact exposures to PCBs on walls, ceilings and other indoor school surfaces.  USEPA method wipe tests are used to evaluate surfaces for PCBs.  Wipe tests performed at the Malibu schools this summer found that PCBs were below USEPA’s concern level.  Thus, PCBs on building surfaces do not pose a risk.

Results of PCB Testing of Caulking

Caulking is the pliable material used to fill the narrow gaps between windows, walls and doors.  It is also used to fill joints between different construction materials like brick and concrete.  Ideally, caulk should remain soft and pliable for decades, but in practice this is hard to achieve.  When added to caulk, PCBs were terrific at helping caulk achieve these goals; until its use was banned.

Caulk is a building material often found with high PCB concentrations.  Some caulk samples from the Malibu schools do contain PCBs at greater than the USEPA limit, but this result has no bearing on health risk.  The positive air tests and wipe tests are relevant to health risk, the caulk tests are not.

Overall Evaluation of PCB Health Risk

Based on the test results for both Malibu schools, there does not appear to be cause for concern about adverse health effects from PCBs at the schools for either students or staff.

The Bigger PCB Issue

It’s well worth noting that no correlation has been found between the presence of PCBs in schools and adverse health effects in either students or staff.  This result is not surprising when you consider that the PCB exposure students and staff may receive is hundreds of times less than the amount required to cause a human health effect.

In fact, scientists have known for some time that risks from PCBs were seriously exaggerated as a result of a 1968 poisoning incident in Japan.  This incident, known as the Yusho rice oil poisoning, was thought to have been caused by PCBs and it received wide international attention.  It was not until many years later that Japanese scientists using better equipment discovered that the poisoning had not been caused by PCBs.  However, by then PCBs had been banned across much of the globe.

Almost every press article about PCBs includes these words in the opening line: either “cancer causing PCBs were discovered . . . ” or “probable cancer causing PCBs were discovered . . . “.  However, the scientific evidence (and there is quite a bit of this evidence) indicates that PCBs do not cause human cancer.  PCBs can cause liver cancer in rats, but rat liver physiology is different than human liver physiology.  Evidence of a link between PCBs and human liver cancer has not been found.

So while arguments about the risks from PCBs in schools are likely to continue, the science on human PCB toxicity is largely settled.  Remember that generations of students attended these same schools with these same PCBs for decades before anyone ever thought about it.  Everything points to these Americans being the healthiest and longest lived of any generation yet.