Understanding what PCBs are, their health effects, and how to properly identify, abate, and dispose of them allows companies to develop accurate bid specifications; estimate project costs; protect workers, clients, the public, and the environment; and reduce company liability. If not handled properly, PCB-related projects can expose a company to legal and financial risk and reputational damage.

PCBs are synthetic organic chemicals sharing similar structures and properties. They were widely used in building products from the 1920s until their ban in 1979 under the Toxic Substances Control Act (TSCA). There are 209 different types of PCBs, known as congeners.

PCBs used in building materials are mixtures of these congeners. PCBs are typically colorless to light yellow and range in consistency from oil to a waxy solid. They have no known taste or odor and can off-gas into the air as vapors. The chemical properties that made PCBs useful in manufacturing – such as non-flammability, chemical stability, and insulating capabilities – also make them environmentally persistent and harmful to humans, animals, and ecosystems.

PCB Prevalence in the Built Environment

PCBs have been found in many building materials, including:

• Caulking
• Coatings and paints
• Window glazing
• Gaskets
• Dielectric fluids used in transformers, capacitors, and high-voltage cables
• Rubber & plastics
• Adhesives and sealants
• Inks and pesticide carriers
• Hydraulic and heat-transfer fluids
• Fluorescent light ballasts
• Ceiling tiles, flooring materials, and mastics
• Structural fireproofing

From 1958 through 1971, more than 75 million kilograms of PCBs were sold in the United States for use in industrial products (NIOSH, 1975).

Due to the widespread use and large production volume of PCBs, they may be present in many buildings. An estimated 800,000 government and non-government buildings – comprising roughly 12 billion square feet of interior space – were constructed between 1958 and 1971 and could contain PCBs (EIA, 2008). Approximately 46% of U.S. schools – about 55,000 – built during that period likely contain PCBs based on indoor air quality surveys (Moglia et al., 2006).

The Environmental Protection Agency (EPA) estimates that cleaning up PCB-contaminated buildings across the U.S. could cost between $150 and $200 billion. Due to the high likelihood of contamination in buildings constructed before 1979, it is important to understand the associated health effects, environmental impact, and worker safety concerns.

PCBs were used and later banned during the same time period as other well-known hazardous materials, such as asbestos and lead, and are often found in combination in older buildings.

Health Effects of PCB Exposure

PCBs are lipophilic – meaning they accumulate in fat tissue and persist in the body and environment. Human exposure occurs primarily through ingestion of contaminated food, especially fish, meat, and dairy products. Inhalation and skin contact, especially in occupational settings, are also important exposure routes. Short-term (acute) exposure to high levels of PCBs can result in:

• Chloracne (a severe skin condition)
• Skin rashes and irritation
• Eye and respiratory tract irritation

Long-term (chronic) exposure has been associated with:

• Increased cancer risk – PCBs are classified as probable human carcinogens by the International Agency for Research on Cancer (IARC) and the EPA
• Liver and biliary tract cancers
• Possible breast cancer

Non-cancer chronic effects include:

• Suppressed immune function
• Endocrine disruption
• Neurodevelopmental delays in children (lower IQ, attention deficits, and other developmental impairments)
• Cardiovascular disease, thyroid dysfunction, and reproductive effects in adults

Environmental Issues

PCBs are classified as persistent organic pollutants (POPs) – meaning they do not easily degrade and can remain in the environment for decades. Due to their persistence and global distribution, PCBs were banned under the Stockholm Convention on Persistent Organic Pollutants in 2001. They can travel long distances through the atmosphere and have been detected in remote regions such as the Arctic. In the environment, PCBs bind to soils and sediments, bioaccumulate in aquatic organisms and move up the food chain, affecting fish, birds, and mammals (e.g., humans). Environmental impacts include documented reproductive failure in animals, immune system suppression and developmental abnormalities in wildlife.

Worker Health and Safety Concerns

Workers in construction, manufacturing, remediation and waste management have historically been exposed to PCBs through inhalation of vapors or dust and direct skin contact with PCB-containing materials.

Although the Occupational Safety & Health Administration (OSHA) does not have a specific standard for PCBs, it does enforce permissible exposure limits (PELs) for workplace air concentrations of 1.0 mg/m³ for PCBs with 42% chlorine and 0.5 mg/m³ for PCBs with 54% chlorine.

However, since PCBs are probable human carcinogens, any exposure should be considered potentially harmful.

To protect workers, employers must abide by their hazard communication program and provide required training; ensure the use of appropriate Personal Protective Equipment (PPE); conduct exposure assessments; and implement exposure controls. Additionally, employers need to train workers in safe handling, contamination control, decontamination, and PCB waste disposal procedures. Worker safety is particularly critical during construction operations or remediation and abatement projects involving PCB contaminated materials.

Legal and Regulatory Considerations

Due to the health and environmental risks of PCBs, several regulatory frameworks govern their use, cleanup, and disposal.

The Toxic Substances Control Act (TSCA) of 1976 banned the manufacture, processing, and distribution of PCBs. Under TSCA, the EPA has the authority to regulate:

• Storage and disposal
• Cleanup of contaminated materials and sites
• Reporting requirements for PCB incidents

The EPA’s 40 CFR Part 761 regulations define “PCB remediation waste” and set standards for allowable levels – including a cleanup level of one part per million (ppm) for high-occupancy areas without further restrictions; while waste containing over 50 ppm of PCBs (e.g., soil, caulking) is classified as hazardous and must be disposed of in regulated facilities.

Many materials installed before 1980 may contain PCBs and should be tested prior to disturbance. State and local regulations may also require testing and compliance with specific demolition or disposal protocols. Special caution should be taken with materials like caulking and paint, which are common sources of PCB contamination.

In addition to TSCA, the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) or Superfund holds parties financially liable for the cleanup of PCB contamination. This has led to major legal actions and multimillion-dollar settlements against companies responsible for PCB pollution.

HETI…Providing PCB Management Assistance

Even decades after their ban, PCBs continue to present serious health, environmental, and legal challenges. Their persistence in older buildings and ecosystems, combined with their toxicity, make them a top concern for environmental health and occupational safety. By understanding where PCBs are found, how exposure occurs, and how to manage cleanup safely and legally, companies can protect workers and occupants, limit their liability, and ensure their environmental and legal compliance.

HETI’s staff of certified industrial hygienists and environmental professionals can assist clients with proper testing, abatement, and disposal procedures for PCB-containing building materials and soil/water contamination – critical for managing PCB risks effectively.

To find out more about this and other HETI industrial hygiene services, please contact us. Bernie Mizula, MS, CIH, CSP, CIT, RPIH Senior Industrial Hygienist

Vapor intrusion (VI) occurs naturally as volatile or semi-volatile contaminants emit from soil, groundwater, or their interface and impact the interior space of buildings above. This impact can occur directly, such as when contaminated groundwater flows into a basement sump pit, or indirectly, where soil gas carrying vapor-phase contaminants is pulled into the building through plumbing and electrical chases. The types of chemicals can include:

• Volatiles: hydrocarbons (e.g., gasoline), solvents (e.g., toluene)
• Semi-volatiles: perchloroethylene, diesel fuel, creosote, etc.
• Metals: mercury, etc.
• Inorganic gases: radon, ammonia, etc.

Once inside a building, occupants can be exposed to these vapors, and, in some cases, at levels that could be hazardous. As a result of these potential exposures, federal and state regulatory agencies have moved to provide resources for building owners, occupants, and technical experts to assess risk and control exposures.

State of Regulation

The United States Environmental Protection Agency (USEPA), as well as nearly all state governments and the District of Columbia, currently provide general guidance for assessing and controlling VI in homes and businesses. However, some states, such as Massachusetts, New Jersey and Pennsylvania, do have more specific regulations regarding protocols for testing structures close to any known subsurface contamination. These regulations indicate that when subsurface concentrations of volatiles are known to exist above an established level (typically called a “screening level”), then nearby buildings should be tested to determine if VI is occurring.

Other regulations will apply to VI, such as those regarding limits of subsurface contamination. In addition, state agencies can compel VI assessments. Also, if VI impacts a commercial or industrial building, the Occupational Safety & Health Administration (OSHA) Permissible Exposure Limits and Short-Term Exposure Limits apply to the occupants.

For example, in the case of gasoline-contaminated shallow soils, causing VI in a warehouse, the owner of the warehouse is obligated to ensure that the employees therein are safe. Gasoline is a volatile mixture of dozens of chemicals, including benzene, toluene, xylene, hexane, etc., each with its own exposure limit. Proper indoor air assessment will determine which chemicals are present, and if any are found in concentrations above the OSHA limits, controls will have to be instituted to ensure worker safety.

For residential structures, the most relevant exposure limits are Reference Doses (RfDs) established by USEPA. Although some RfDs are contested as being overly conservative, these limits are extrapolated from published, peer-reviewed toxicology studies, and establish a limit below which exposure is safe to an average human continuously for 70 years.

Technology to Assess and Control Intrusion

Assessing the presence of VI can be a difficult proposition. Typically, the interior of a potentially affected building is tested over a minimum 24-hour period using various methodologies. For example, if a subsurface contamination plume intersecting a building is composed of diesel fuel, which contains dozens of potentially hazardous chemicals, USEPA’s sampling and analysis method TO-15 is often employed. This method can detect hundreds of chemicals at very low concentrations. TO-15 requires that samples be placed on the floor of the lowest level when possible, to detect chemicals as they enter the building airspace. They are also often located close to penetrations in the foundation, such as pipes, electrical wires, or sump pits.

In addition, testing below the foundation could be appropriate, especially in locations where multiple contamination plumes may be present. This is typically accomplished by installing soil vapor probes through the foundation and then testing the air entering the probes at various depths to determine what chemicals are entering the building above.

If vapors are detected above established human safety levels, there are several ways to mitigate them. Most common is a “radon fan” – which can intercept vapors before they enter the building – consisting of a tube or pipe running from beneath the building’s foundation to, typically, above the roofline of adjacent buildings. An electric fan installed in the system pulls the vapors from the subsurface and vents them into open air, bypassing the interior of the building.

In extreme cases, or with new construction in an area with known potential for VI, a vapor barrier can be installed beneath the building’s foundation to prevent vapors from entering the building. Typically a thick plastic sheeting is installed in a continuous layer below the foundation as a vapor barrier. A permeable layer of sand or similar material may be installed above the barrier to allow a concrete foundation to cure and age more evenly, or below the barrier to prevent the buildup of vapors below the building. Note that these vapor barriers will also prevent subsurface moisture vapor from entering the building, preventing moisture damage to any floor coverings or finishes.

In cases where VI potential is high, both referenced technologies can be employed in conjunction with each other to ensure that healthy indoor air quality levels are maintained. No matter what control measure is installed, the building should be tested regularly to ensure that the system functions properly.

HETI…Helping Manage Vapor Intrusion

Vapor intrusion can be a serious concern for any building near subsurface contamination. Testing the building and the subsurface are critical to determine the presence of vapors that may require control.

HETI’s staff of geologists, environmental professionals and industrial hygienists has many years of experience assessing and managing vapor intrusion. We are available to provide valuable technical support to our clients with testing, assessment and establishing appropriate engineering controls, as needed.

For further information about this and other HETI environmental health & safety services, please contact us.

Patrick A. Walsh, CIH Senior Industrial Hygienist

Phone: 978.263.4044 development@hetiservices.com