A growing body of evidence suggests that EHS professionals should take a closer look at polychlorinated biphenyls (PCBs) in the built environment. PCBs have been identified in high concentrations in a number of building materials such as paints, mastics, and caulks, and can be emitted from intact materials. Identification and assessment of PCBs within a built-environment setting is the first step in evaluating whether PCBs are a potential risk to building occupants and construction and building maintenance workers who may come into contact with these materials.

PCBs are a group of man-made aromatic chemical compounds that share a similar biphenyl chemical structure. Each PCB compound has between one and 10 chlorine atoms. Based on the position of the chlorine atoms, there are a total of 209 different PCB compounds, also referred to as congeners.

In the United States, PCBs were manufactured from 1929 until 1979, primarily by the Monsanto Chemical Company, most commonly under the trade name Aroclor. PCBs range from viscous liquids to wax-like solid materials and were valued for their high dielectric constant, thermal and chemical stability, and low vapor pressure, among other physical and chemical properties. PCBs were used in a number of commercial applications including closed-system products such as dielectric fluids in transformers, capacitors, and light ballasts; partially closed system products such as hydraulic and heat transfer fluids, switches, and voltage regulators; and open application systems such as lubricants, waxes, adhesives, paints, caulks, and sealants. Manufacturing data for 1970, the peak of PCB production in the U.S., indicate that 85 million pounds of PCBs were produced, of which 56 percent was reportedly used in closed applications, 30 percent in open applications (for example, plasticizers in materials such as paints and caulks), and 12 percent in hydraulic fluids.

The use of PCBs in building materials appears to be a widespread concern. A 2004 paper in identified buildings constructed or renovated from the 1950s to the 1970s as those most likely impacted by the use of PCB-containing materials. Research in the journal that at least 154 million pounds of PCBs were sold for use in open application-type products from 1958 to 1971 and estimates that 46 percent of public and private schools were constructed between 1950 and 1970 when PCBs were in use in open-application building products. And a 2010 study of PCBs in sealants, published in , found that 14 percent of buildings surveyed in Toronto, Canada contained detectable quantities of PCBs (0.57 mg/g to 82 mg/g, n=95) in sealants. According to EPA, the largest source of exposure to PCBs among the general population is consumption of seafood, meat, and dairy products. For building occupants where PCB-containing materials are present, exposures may occur from inhalation of PCB vapors emitted from primary sources, such as light ballasts, paints, and caulks. Secondary sources can occur where PCBs have been absorbed into substrates from leaks or spills or adsorbed from gaseous emissions into porous materials. Another exposure source includes ingestion of PCB-containing dusts on contaminated surfaces. Environmental Health has documented airborne PCB concentrations exceeding EPA’s recommended public health guidelines in schools with PCB-containing components and building materials. By the mid-to-late 1970s, concerns regarding bioaccumulation and the persistence of PCBs in the environment resulted in the regulation of PCBs under TSCA. TSCA PCB regulations contain a number of restrictions and prohibitions on the manufacture, use, and disposal of PCB materials in the U.S. Much of the TSCA PCB regulations focus on liquid forms of PCBs (for example, dielectric liquids in transformers) and the associated impacts to soils and surfaces from spills. With respect to PCBs in building materials and the built environment, unless specifically exempted under TSCA, materials that contain greater than 50 parts per million (ppm) of PCBs are considered an “unauthorized use” and must be removed. TSCA regulations, however, do not require that a building owner or property manager conduct an assessment to determine if PCBs are present in building materials unless activities are planned that could generate waste streams containing PCBs during renovation, repair, or demolition activities. Application of the TSCA regulatory framework to PCB-containing building materials and components is based on the following factors:

1. nature and extent of migration from the PCB-containing building material to surrounding substrates
   
2. concentration of PCBs present in the building material
   
3. determination of PCB waste classification status, including PCB bulk product waste, PCB remediation waste, and excluded product
   
4. location of PCB-containing building material
   

The first step in identifying and assessing suspected PCB-containing building components and materials is to examine some of the most common PCBs sources in buildings built or renovated between 1950 and 1979. In most cases, the determination of PCB content is made by collecting representative bulk samples of suspected PCB-containing building materials and submitting the samples for laboratory analysis. Appropriate personal protective equipment (PPE) should be used when collecting bulk samples from suspected PCB-containing materials. The PPE typically used would be similar to that used during collection of bulk samples for determination of asbestos or lead content. EPA advises that PCB-containing fluorescent light fixtures may be present in buildings constructed before 1979. The T12 fluorescent light ballast (FLB) may contain PCBs in the interior potting material and the capacitor portion of the ballast. The older T12 FLBs are prone to leaks and rupturing due to the length of time they’ve been in service. In addition, PCB-containing FLBs are known to emit vapor-phase PCBs during normal use. T8 and T5 FLBs are not known to contain PCBs.

When conducting an assessment, a visual inspection of the FLB should be completed to determine if PCBs may be present based on the manufacture date and the following criteria:

• Ballasts manufactured after July 1, 1998, are not required to be labeled, but many manufacturers label them anyway.
  
• Ballasts that were manufactured between July 1, 1978, and July 1, 1998, and that did not contain PCBs, were required to be labeled “No PCBs.”
  
• Ballasts that are not labeled “No PCBs” should be assumed to contain PCBs unless known to be manufactured after 1979.

Other common sources of PCBs in buildings built or renovated between 1950 and 1979 are caulking and elastic sealants. PCBs were used as a plasticizer to enhance the pliability and durability of these materials. Common product applications included caulking used to seal joints in masonry around windows and doors, stairwells, and building expansion joints. EPA has reported concentrations in caulks and sealants ranging from less than 50 ppm to greater than 440,000 ppm. Exposure to PCBs can occur due to off-gassing of vapor-phase PCBs in intact caulks and sealants. Deteriorated caulks and sealants can lead to PCB-containing dust and debris, which can contaminate adjacent surfaces and soils. Migration of PCBs from caulks and sealants into surrounding or adjacent porous substrates such as wood and concrete is well documented.

A visual inspection of representative building caulks and sealants should be conducted at the start of the assessment. The inspection should be made to identify and determine the location, quantity, homogeneity, and condition of caulks and sealants. Homogeneous caulks and sealants should be grouped together for sampling purposes, and information including material locations, color, and use of each homogeneous material type should be recorded.

Samples should be collected by personnel wearing appropriate PPE and using hand tools such as disposable stainless steel scalpels or utility blades. If disposable sampling equipment is not used, field sampling equipment must be appropriately decontaminated between sample collections. Each sample should be collected in a pre-cleaned amber glass jar with Teflon-lined cap, labeled with a unique sample number and shipped chilled (4°C) to a qualified laboratory. Surface contamination can occur due to spills of liquid PCBs, settled dusts from deteriorated PCB-containing materials (for example, caulks or paints), and from run-off due to rain or other weather onto PCB-containing materials, typically in exterior areas of a building or structure. Surface wipe sampling can be conducted using PCB wipe kits. A standard PCB wipe kit will include a PCB-free wipe material such as cotton gauze, stored in amber glass vials with Teflon-lined caps and with a small amount of hexane to act as the wipe solvent. The wipe kits can be provided by a qualified laboratory prior to sampling.

Wipe samples should be collected from within a known surface area, usually standardized to 100 square centimeters if possible, using a PCB-free template material. If an irregular shape or surface geometry prevents the collection of a 100 cm2 sample, the actual area wiped should be recorded by the sampler. Wipe samples should be labeled with a unique sample number and shipped chilled to a qualified laboratory. Evaluation of soil contamination may be recommended in situations where PCBs are identified in exterior building materials such as caulks and paints. These exterior materials are exposed to weather and other deteriorating elements such as ultraviolet radiation, which can cause them to become brittle and degraded, and lead to contamination of surrounding soils. Soil contamination is typically limited to the soils closest to the building exterior. Representative soil samples should be collected from multiple locations starting close to the building exterior and moving outwards. Samples collected from suspected PCB-containing building materials and soil should be analyzed by a qualified, accredited, state-certified laboratory to determine total PCB content. Several analytical methods are available to determine PCB content.

The most common laboratory analytical method is PCBs as Aroclors (EPA SW-846 8082A), which uses low-resolution gas chromatography equipped with electron capture detectors or electrolytic conductivity detectors. The results are reported as seven Aroclor types (1016, 1221, 1232, 1242, 1248, 1254, and 1260). Interpretation of the chromatographic peaks can be difficult because the composition of PCB congeners in a building material can change over time due to loss of volatile congeners. This phenomenon, commonly referred to as “weathering,” makes comparison against known Aroclor standard chromatograms more difficult. PCBs as Aroclors is a relatively low-cost method and is widely available commercially.

The method PCBs as Homologs (EPA SW-846 8270D / EPA Method 680) is based on the fact that there are 10 groups of PCB congeners, all of which have the same number of chlorine atoms attached to the biphenyl ring in different positions. Analysis of PCBs as Homologs is conducted using gas chromatography/low-resolution mass spectrometry (GC/LRMS). The method is generally considered more accurate in determining total PCBs than PCBs as Aroclors, but it is also more expensive and not as widely available.

The method PCBs as Congeners (EPA SW-846 1668B) is able to differentiate each of the 209 PCB congeners using high-resolution gas chromatography/high-resolution mass spectrometry. Compared to PCBs as Aroclors and PCBs as Homologs, the PCBs as Congeners method can achieve lower detection limits but is more expensive and not as widely available.

The interpretation of PCB bulk and surface sampling results for clean-up and disposal requirements is outlined in TSCA and any applicable state regulations. EPA defines PCB bulk product waste as waste derived from manufactured products containing PCBs in a non-liquid state, at any concentration where the PCB concentration at the time of designation for disposal is greater than or equal to 50 ppm.

PCB remediation waste, as defined by EPA, is waste that has become contaminated as a result of a spill, release, or other unauthorized disposal of PCBs. This includes environmental media, such as soil, sediments, gravel, sewage, and industrial sludge, rags, and other debris generated as a result of any PCB spill cleanup, as well as building materials (for example, concrete, masonry). Industrial hygienists are well suited to take a leading role in the anticipation, recognition, evaluation, and control of PCBs in building materials. Beyond the initial steps of identifying and assessing PCB content in building materials, there are a number of activities that may be useful after PCBs are suspected or have been identified. You can conduct air sampling to determine ambient indoor PCB levels to evaluate exposures for building occupants. You can implement best management practices to minimize health risks from PCB-containing building materials to building occupants and maintenance or construction personnel. You can develop clean-up plans that protect building occupants and remediation workers during removal activities. You can coordinate and interact with regulatory agencies before, during, and after removal activities to help ensure compliance with applicable state and federal regulations. And finally, you can communicate the risks to building occupants, maintenance or construction workers, and other stakeholders.

AIHA: “Assessment and Remediation of PCBs in the Built Environment” (2017).

Agency for Toxic Substances and Disease Registry: (PCBs) (November 2000).

“Continuing Sources of PCBs: The Significance of Building Sealants” (August 2010).

“Mitigation of Building-Related Polychlorinated Biphenyls in Indoor Air of a School” (2012).

“An Unrecognized Source of PCB Contamination in Schools and Other Buildings” (July 2004).

EPA: “.”

EPA: Method 1668B Chlorinated Biphenyl Congeners in Water, Soil, Sediment, Biosolids and Tissue by HRGC/HRMS (November 2008).

EPA: (February 2007).

EPA: Method 8270D: Semivolatile Organic Compounds by Gas Chromatography/Mass Spectrometry, (, July 2014).

EPA: “PCBs in Building Materials—Questions & Answers” (, July 2015).

EPA: Polychlorinated Biphenyls Inspection Manual (2004).

NIOSH: (PCBs) (November 1975).

United Nations Environment Programme: Guidelines for the Identification of PCBs and Materials Containing PCBs (1999).