Identifying the environmental liabilities embedded in real property is the goal of environmental site assessments. For obvious reasons, the purchaser (and their lender) would prefer to have this settled before any transaction takes place. With environmental remediation often coming at such a high price, ignorance of environmental liabilities can easily make the difference between a mutually beneficial deal and a financial disaster for one party. While these assessments typically evaluate contamination of soil and groundwater and the presence of leaking drums and underground tanks, they often ignore building materials that could contain polychlorinated biphenyls (also known as PCBs). Is this an oversight? And if it is, how serious is it?

Got PCBs?

PCBs were used in a wide variety of building materials prior to their ban in the 1970s. While this is hard for us to fully comprehend today, PCBs were one of the “miracle chemicals” of their day, as a result they were added to many, many products; this was the era of “better living through chemistry”.

The best known uses of PCBs in building materials were in caulk and paint, but PCBs are just as likely to be found in adhesives, floor finishes and concrete form release oils – to name a just a few applications. There aren’t any good statistics on this, but odds are that a building built before 1980 has a 50% chance of containing PCBs; whether its use is institutional, commercial or residential.

There’s only one way to know for sure whether a building has PCBs, and that’s to collect samples and test them. But there’s a big problem with this simple approach, testing a building for PCBs is opening Pandora’s Box; an innocent act that risks lots of unintended consequences. While there’s no requirement to test building materials for PCBs, this often well intentioned act can trigger a cascade of PCB liabilities. Testing building materials for PCBs is often compared to playing Russian roulette.

What’s the Downside?

Until the last decade, the question of PCBs in buildings was largely academic, but that’s changing fast as experience shows PCB remediation costs are too high to ignore. The change is due to USEPA’s shifting policy towards PCB enforcement.

When the first PCB regulations were issued in 1978-79, they contained a provision known as the “in-service rule” that permitted the continued use of existing PCBs in building materials; no new PCB building materials could be added, but the existing stock was grandfathered–in. But, when EPA rewrote the PCB regulations in 1998, they quietly eliminated the in-service rule. The result was that all the PCB caulk, paint and window glazing in hundreds of thousands of buildings was suddenly outlawed. This change was not made because EPA determined that PCBs in building materials were dangerous, in fact it was made for reasons completely unrelated to PCBs in buildings.

Although there is no requirement for testing, once an owner determines that a building contains PCBs the only lawful option is to remove them. But taking PCBs out of a building is no easy task; over decades PCBs slowly move out of the caulk or paint where they started and into abutting concrete, brick or wall board. Removing PCBs from these abutting materials has proven to be much more expensive than removing the caulk or paint itself.

On top of the direct PCB removal costs it would be wise to also consider  EPA’s extra-regulatory requirements, such as the confirmation of cleanup effectiveness through air testing; total project costs quickly become unpredictable. What might have started as an expensive but manageable $100,000 cleanup can readily grow to an unmanageable multimillion dollar cleanup, with no end to the costs in sight. Abandoning otherwise useful buildings can become the only option.

Location, Location, Location

As the old saying goes, when it comes to real estate,  nothing is more important than location; as it turns out this is true of the PCB regulations too. At least for now, EPA’s PCB enforcement program is not implemented consistently across the country. Program implementation is in the hands of the 10 EPA Regional Offices, and each of these sets its own priorities. So while PCBs in building materials are a hot topic with EPA in New England, they are rarely discussed in the Southeast (just one example).

What to do?

If you own or are responsible for a building that may contain PCBs, at some point you will need guidance on what your options are. If the only advice you are receiving is from people telling you that you need to test the materials, consider whether it’s time to find a new adviser. There are other alternatives besides testing. And even if testing is your best (or only) option, you should go into it with your eyes open, aware of the potential risks and possible strategies to reduce those risks.

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.

While the first alarms bells about PCBs in school buildings may have sounded in New England, the echo of that call-to-arms can now be heard on the west coast.   The discovery of PCBs in Malibu California schools and the press coverage that followed, have shattered the myth that PCBs in schools are only found in older east coast buildings.  For those following the Malibu PCB news, it’s hard to deny the drama that only southern California brings to a story; it’s not hard to imagine this  being the basis for a made for TV movie.

What are the facts?

According to a Fact Sheet dated July 27, 2014 by the Santa Monica-Malibu Unified School District (SMMUSD) an evaluation of school building environmental quality was started after three Malibu High School employees were diagnosed with thyroid cancer.  Following consultation with California environmental and health agencies, the district retained Environ, an environmental engineering firm to assess conditions in the Malibu High School and in the Juan Cabrillo Elementary School.

Environ’s evaluation included testing air, surfaces and certain building materials (paint and caulk) for PCBs.  Note that there is no known correlation between PCB exposure and human or animal thyroid cancer.  While PCBs were found throughout the schools, the detected concentrations were in most case well below USEPA regulatory and public health levels.  No air concentrations exceeded EPA recommended levels, although some caulk samples contained PCB concentrations greater than EPA’s 50 ppm regulatory criteria.

On August 14, 2014 the USEPA Region 9 Regional Administrator issued a letter in which he approved of the plans and actions taken by SMMUSD without exception.  The next day the SMMUSD issued a press release which informed the public that the district’s response to PCBs in the schools had won the endorsement of the USEPA.

What was the public reaction?

In 2013, after PCBs were found in the schools, an organization called Malibu Unites began seeking more testing and ultimately the removal of PCBs from the schools.  The group boasts a membership that includes “parents, teachers, community members, celebrity environmentalists, medical professionals, scientists, and environmental organizations working together for healthy, toxin-free schools”.   The presence of “celebrity environmentalists” has drawn a good deal of attention and press coverage to the group.

Here is an excerpt from an August 29, 2014 article published in the Los Angeles Register that helps convey the sense of frustration felt by the more concerned public:

“Unhappy with the school district’s current clean-up plan, Mayor Skylar Peak said he plans to demand further testing of toxic chemicals at the city’s public schools.

“The City of Malibu doesn’t have any control over its public schools because of state law, but council members decided to put the item on the next agenda after more than an hour of public comments from concerned parents during Monday’s City Council meeting.

“At least 24 parents have taken their children out of Malibu public schools because of elevated levels of PCBs – polychlorinated biphenyl – found in at least five classrooms at Malibu High School.  PCBs are found in window caulking, and sometimes the lighting, of structures built from the 1950s until the chemical was banned by the federal government in 1979.

“Parents and Peak want the district to test the source: the caulk.  The district says the classrooms are safe to re-enter.  Currently, the district is relying on “best practices” of cleaning, dust sampling and air sampling to identify PCB levels”.

Also, a notice of intent to sue the district and the EPA pursuant to the Toxic Substances Control Act was served by the Vititoe Law Group and the Public Employees for Environmental Responsibility (PEER) on August 20, 2014.   The notice gives SMMUSD 60 days to remove toxic materials from the schools or face a federal lawsuit.

Is Malibu the tipping point for PCBs in schools?

In his 2000 best-selling book “The Tipping Point”, Malcolm Gladwell explored the process by which some trends achieve great popularity, while others eventually fade.  The issue of PCBs in schools and other buildings has been simmering just below the surface of public awareness for several years, but outside of the small community of regulators, environmental lawyers and technical consultants, the full potential significance of PCBs in schools and other  buildings has not been understood.

For this post I am not offering my own analysis or opinion about the specific circumstances or health risks associated with PCBs in the Malibu schools.  What I am questioning is whether the Malibu PCB situation may draw sufficient public awareness that it becomes the tipping point that triggers an increased national awareness and policy development regarding PCBs in schools. We’ll see.

 At the end of May I posted an article that reviewed the routes of exposure by which people are exposed to PCBs.  After some general discussion, the article focused on the total PCB intake for three elementary school-aged child receptors who attended schools with different indoor air PCB concentrations:

• A school with a relatively low 100 ng/m³ (nanograms per cubic meter) of PCBs in air;
•  A second school with 300ng/m³ of PCBs in air (this is the EPA Public Health Level); and
•  The third school with 400 ng/m³ of PCBs in air, 33% greater than the EPA Public Health Level.

The article calculated a total average daily dose of PCBs for these different student receptors by adding the amount of PCBs they ingested each day from food (this worked out to be 11.8 ug/day, aka micrograms per day), to the amount of PCB they inhaled at school and the amount they inhaled at home.  Recall that there are 1,000 ng in 1.0 ug.  Here is the summary table I ended up with:

Table 3 – Percentage of Daily PCB Exposure from Food and Air

The article’s conclusions were: 1) for these student receptors the overwhelming majority of their daily PCB dose comes from their diet; and 2) trying to reduce their daily PCB intake by reducing the concentration of PCBs in school air was a poor use of limited school resources because the proportion of the student’s daily PCB dose coming from air was too small to be of consequence.

What Happens When PCB Air Concentrations are even higher?

Let’s say you are growing a little skeptical about the potential health benefit of reducing PCBs in indoor air when the reduction is from 400 to 300 ng/m³.  But, what if the original indoor air PCB concentration is much higher than 400 ng/m³, what if it were 800ng/m³ (new Scenario 4) or 1,600 ng/m³ (new Scenario 5)?  Okay, take a look at Table 4:

Table 4 – Updated Sum of PCB Daily Exposures from Food and Air (in ug)

What I’ve done here is added the average daily dose of PCBs from food to the average daily dose of PCBs from air for our hypothetical elementary school students.  Scenarios 2 and 3 are the same as before, but new Scenarios 4 and 5 incorporate more extreme indoor air concentrations.  Scenario 5 is an unusually extreme indoor air concentration of PCBs.

Table 5 (below) uses the information just presented in Table 4 to identify what percentage of the student’s average daily PCB intake is coming from food and air with the new scenarios 4 and 5.

Table 5 – Percentage of Daily PCB Exposure from Food and Air

Table 5 shows that even when elementary school indoor air concentrations reach 1,600 ng/m³, only 27% of an elementary school student’s daily dose of PCBs would be from air (mostly from school air, but some from air at home too).

The Upside of Removing PCBs from Schools

Finally, Table 6 identifies the percentage reduction in average daily student PCB intake that can be achieved by reducing the indoor air concentration to the EPA Public Health Level of 300 ng/m³:

Table 6 – Percent of PCB Exposure Reduction from Reducing Indoor Air Levels

A Lot of Pain to Reduce PCB Air Concentrations, but is there Real Gain?

A conclusion that I did not highlight in the earlier article is that bringing indoor air concentrations down from 400 ng/m³ (a level well above the EPA public Health Level) to 300 ng/m³ will reduce a student’s average daily PCB intake by roughly 2%.  From a toxicological standpoint a 2% reduction cannot be expected to have any discernible health benefit, in fact it is almost certainly a difference too small to measure using even advanced methods.

      By reducing an indoor air concentration from 800 ng/m³ to 300 ng/m³ the total dose reduction for an average student would be just under 10%, again this difference in total PCB dose is too small to measure in a student population if the study were to be done.  Just think about the quality control acceptance criteria for PCB analysis (generally results that fall between 70% and 140% of the true value are considered accurate).  It is unlikely that a 10% difference in dose could be reliably detected.

      For scenario 5, the case with 1,600 ng/m³ PCB in air, it is harder to dismiss a potential 21% reduction in PCB dose as inconsequential.  That large a reduction in dose could in-fact be significant from a health perspective if the total dose received were on the “steep portion” of the dose-response curve.  The steep portion of a dose-response curve is the dose range where small changes in dose are most likely to have the biggest effect.  However, in the case of PCBs the steep part of the dose-response curve just begins at doses between 50 to 500 times greater than the doses we have been considering.  In other words, reducing PCB air concentrations in schools, even those as high as 1,600 ng/m³, are unlikely to produce any measurable health benefit because:

1. The PCB dose received from the average student diet is still much greater than the dose received from air; and
2. The total average daily dose of PCBs received by average elementary school children is much less than dose needed to produce detectable health effects.

 It is well known that all people have some amount of polychlorinated biphenyls (PCBs) in their body.  Now the total amount of PCBs we have in us is quite small and there is no real evidence that it is doing us any harm.  But, it is still a good question to ask: how did this happen?  Where did those PCBs come from?  More specifically, what types of exposures caused each of us to acquire our own personal cache of PCBs? 

 When you think the question through, you realize there are really just three possibilities:

 1. We were born with them, in other words we received them from our mothers during gestation in her womb;

2. We absorb PCBs that occur in small amounts from our food; and/or

3. We breathe air that contains small amounts of PCBs and retain them in our bodies.

 Which one of these is the best explanation?  Let’s see what we can figure out.  By the way, in the discussion that follows I am focusing on mean (average) consumers of food and breathers of air.  There are certainly people who for portions of their lives may differ significantly from these means, but most of the population will fall close to these values.

 Were we Born with PCBs?

 It was long assumed that a fetus was protected from drugs and other chemicals present in the maternal blood supply by the action of the placenta and its semi-independent circulatory system.  However, the thalidomide disaster proved that assumption to be false.  From human studies we know that the PCB concentration of umbilical cord blood has roughly half the PCB content of maternal blood.  So while the amount of PCB reaching the fetus from the mother is moderated, it is not eliminated.

 Still, we also know that young children generally have low to non-detectable concentrations of PCBs in their blood.  This may reflect a more rapid rate of PCB excretion for children, or it may be that the total body burden of PCBs received from the mother is small.  So while some portion of an adult’s PCB body burden may have been received from her/his mother during fetal development, the role of maternal PCB transfer to her infant appears to be small and transient.

 PCBs from Food

 It has been known for some time that PCBs are present throughout the human food supply.  The concentration of PCBs in food has been declining for decades and currently ranges from 2-6 micrograms of PCBs per kilogram of food (ug/kg) for fruits, vegetables and grains to 10-50+ ug/kg for chicken, meat, oils, butter and fish.

 To estimate the average daily PCB consumption from food, we need to know how much of the different types of food the average person eats, and the average PCB concentration in that food.  To keep things simple, I am assuming 100% of the PCBs ingested with food are absorbed into the body; a reasonable assumption in most cases.

 Using the USDA data on the average American food consumption and a mid-point in the range of PCB concentrations by food type I calculate that the average American consumes about 15.7 micrograms of PCBs per day in their food.  For comparison a person with a vegan diet (consuming no dairy or meat), the total PCB intake from food would be about 8.9 micrograms per day. 

 For the scenarios considered in the following section, I’ve reduced the average American dietary intake by 25% because the receptor in the exposure scenarios is an elementary school child (1,500 calories/day).  This results in a corresponding 25% reduction in PCB intake (11.8 ug/day for regular diet; 6.68 ug/day for a vegan diet).  If you would like to see my spreadsheet for these calcs please send me an email and I will forward them.

 PCBs from Air

 To estimate the average exposure to PCBs in air we need to know the breathing rate for the average elementary school student and the average PCB concentration in the air they breathe.  Table 6-1 of EPA’s Exposure Factor Handbook is a good source of information on breathing rate.  In the interest of simplicity, I am going to use a breathing rate of 12 cubic meters of air per day (m³/day) for the student. 

 This would be low for an adult and about right for a child.   Someone who is physically exerting themselves will have a much higher breathing rate while the activity lasts, but I am more interested in long-term average exposures than in peak short-term exposures.

 PCB background concentrations in outdoor air can be as low as 0.05 ng/m³ in remote areas and as high as 10 ng/m³ in outdoor urban environments (note that ng/m³ means nanograms per cubic meter; also note that 1,000 ng = 1.0 ug) .  Published data on indoor air PCB concentrations in cases where there is no PCB source material in the building is hard to find. 

 For the purpose of this post, I’m considering three theoretical air exposure scenarios:  

1) a student who lives in a home with 20 ng/m³ PCB in air who attends school in a building 32.5 hours/ week, 36 weeks/year with 100ng/m³ PCB;

2) a student who lives in a home with 20 ng/m³ PCBs in air who spends 32.5 hours per week 36 weeks/year in a building with 300 ng/m³; and

3) a student who lives in a home with 20 ng/m³ and who spends 32.5 hours/week, 36 weeks/year in a building with 400 ng/m³ PCBs.

 The indoor air concentration of 300 ng/m³ corresponds to the USEPA Public Health Level for elementary school age children.  The 400 ng/m³ indoor air concentration corresponds to a level 33% greater than the USEPA Public Health Level for elementary school age children.  Once again, if you’d like to see the spreadsheets, send me an email and I will pass them along.  For simplicity I’m assuming these individuals spend no time at all outside.  The following table shows the results.

Table 1 – Exposures to PCBs in Air

Total Daily PCB Exposure

The sum the PCB exposures from eating and breathing are shown in Table 2:

Table 2 – Sum of PCB Daily Exposures from Food and Air (in ug)

Finally in Table 3 let’s consider what percentage of daily PCB exposure comes from food and what percentage comes from air:

Table 3 – Percentage of Daily PCB Exposure from Food and Air

From Table 3 it is apparent that the major exposures to PCBs for these student receptors occurs through the diet and only a relatively small proportion is due to inhalation of PCBs in air, unless the air concentrations are significantly greater than 400 ng/m³.  So food appears to be the major route by which people receive their PCB body burden.

Based on this analysis, efforts to reduce human PCB exposure by reducing PCB concentrations in air in a school setting are often fundamentally flawed because the percentage of total PCB dose received through air is not great enough to make a significant difference in total PCB exposure.  Efforts to reduce PCBs in schools through expensive remediation programs can often be particularly misguided during a period of tight educational budgets.

There is an important limitation to this analysis, it only considers indoor air PCB concentrations up to 400 ng/m³.  Now 400 ng/m³ is a concentration well above normal levels, but indoor air concentration can be this high, or even higher, in some situations.  In my next blog post I’ll take a look at PCBs at higher indoor air concentrations.