Polychlorinated biphenyls (PCBs) are a class of 209 synthetic chlorinated compounds that were widely used in electrical equipment, building materials, and industrial applications in Australia until their ban in 1986. When buildings containing PCB materials are damaged by fire, the PCBs are released into smoke and soot — and more critically, the heat of combustion can convert PCBs into polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), which are among the most toxic substances known to science.

What Are PCBs and Where Are They Found in Buildings?

Polychlorinated biphenyls are a family of 209 individual compounds (congeners) consisting of two linked benzene rings with varying numbers of chlorine atoms attached. They were valued for their chemical stability, electrical insulating properties, and heat resistance — the very properties that make them persistent environmental contaminants and biological hazards.

In Australia, PCBs were manufactured and imported until the federal government banned their import in 1986, with a scheduled phase-out of existing PCB-containing equipment extending through the 1990s. However, PCB-containing materials remain in many older buildings and infrastructure. Common sources in fire-damaged buildings include:

• Electrical transformers and capacitors — PCB-containing dielectric fluids (such as Aroclor, Askarel, and Pyroclor) were used in transformers, capacitors, and voltage regulators. Buildings with their own transformer substations (common in commercial and industrial properties) are at highest risk.
• Fluorescent light ballasts — ballasts manufactured before 1980 commonly contained small PCB-filled capacitors. A single building can contain hundreds of ballasts, each with a few grams of PCB fluid.
• Caulking and sealants — PCB-containing caulking compounds were used extensively in concrete and masonry construction from the 1950s to 1970s, particularly around windows, expansion joints, and curtain wall panels.
• Paints and surface coatings — some industrial paints and coatings manufactured before the 1970s contained PCBs as plasticisers.
• Hydraulic fluids and lubricants — PCB-based hydraulic fluids were used in some industrial equipment and building systems.

When PCBs Become Lethal: Dioxin and Furan Formation in Fire

The critical danger with PCBs in fire-damaged buildings is not the PCBs themselves — though they are serious contaminants — but what they become when heated. When PCB-containing materials are exposed to temperatures above approximately 300 degrees Celsius (well within the temperature range of building fires), the PCB molecules undergo thermal rearrangement to form polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs).

Dioxins and furans are among the most toxic compounds ever studied. The most toxic congener, 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD), has health effects at concentrations measured in parts per trillion — thousands of times lower than the thresholds for most other environmental contaminants. The toxicity of dioxin/furan mixtures is expressed as toxic equivalency (TEQ) relative to 2,3,7,8-TCDD.

In our assessments of fire-damaged buildings where PCB sources were present, we have documented dioxin/furan contamination extending well beyond the immediate fire zone, carried by smoke and soot throughout the building and deposited on surfaces, in dust, and within HVAC systems. This contamination represents a serious long-term health risk that is invisible without specific laboratory analysis.

Health Risks: IARC Group 1 Carcinogen and Endocrine Disruptor

PCBs are classified as Group 1 carcinogens (carcinogenic to humans) by the International Agency for Research on Cancer (IARC), based on sufficient evidence of carcinogenicity in both humans and animals. Documented health effects from PCB exposure include:

• Cancer — increased risk of liver cancer, non-Hodgkin lymphoma, and malignant melanoma.
• Endocrine disruption — PCBs mimic and interfere with thyroid and sex hormones, disrupting metabolic, reproductive, and developmental processes.
• Developmental effects — prenatal and early childhood PCB exposure is associated with reduced IQ, impaired cognitive development, and behavioural problems. This makes PCB contamination in residential buildings and schools particularly concerning.
• Immune system suppression — reduced immune function increases susceptibility to infections and may impair vaccine effectiveness.
• Reproductive effects — reduced fertility, altered menstrual cycles, and reduced sperm quality.
• Dermal effects — chloracne (a severe, persistent skin condition) is a hallmark of high-level PCB exposure.

PCBs are highly lipophilic (fat-soluble) and bioaccumulate in the body over time, meaning that even low-level chronic exposure can lead to significant body burden. They are also extremely persistent in the environment, with half-lives measured in years to decades.

Australian Guidelines: NEPM and Safe Work Australia Standards

The assessment and management of PCB contamination in Australia is governed by several regulatory frameworks:

The NEPM (2013) establishes health investigation levels for PCBs in soil: HIL-A (residential with garden/accessible soil) is 1 mg/kg for total PCBs. For commercial/industrial use (HIL-D), the threshold is 7 mg/kg. These are among the lowest investigation levels in the NEPM, reflecting the high toxicity and bioaccumulation potential of PCBs.

Safe Work Australia sets a workplace exposure standard (WES) for PCBs of 0.5 mg/m3 (as chlorodiphenyl, 54% chlorine) as an 8-hour time-weighted average. This applies to workers entering PCB-contaminated buildings for remediation or assessment.

For dioxins and furans, the NEPM (2013) HIL-A for residential soil is 0.00015 mg/kg (150 nanograms/kg TEQ) — a threshold so low it requires specialised high-resolution analytical methods to measure accurately. This extremely low threshold reflects the extraordinary toxicity of these compounds.

State and territory EPA authorities also regulate PCB waste management and disposal under their respective environmental protection legislation. PCB-contaminated materials are classified as hazardous waste and must be disposed of at licensed facilities.

Sampling and Analysis Methods for PCBs After Fire

PCB assessment in fire-damaged buildings requires targeted sampling based on the identified or suspected PCB sources. At Test Australia, our sampling methodology for PCB assessment includes:

Surface wipe samples: Collected from hard surfaces using hexane-moistened wipes, targeting areas near suspected PCB sources and areas of visible soot deposition. Wipe samples are analysed for total PCBs and, where elevated, for individual congener profiles.

Bulk material samples: Collected from soot deposits, dust accumulations, insulation, and building materials. These samples characterise the concentration of PCBs (and potentially dioxins/furans) in the contamination matrix.

Soil samples: Collected around the building perimeter and from areas where firefighting water runoff may have deposited contaminated material. Compared directly against NEPM (2013) HIL values.

Laboratory analysis is performed by independent NATA-accredited laboratories using gas chromatography with electron capture detection (GC-ECD) for screening and gas chromatography-mass spectrometry (GC-MS) for confirmation and quantification of individual PCB congeners. Where dioxin/furan analysis is required, high-resolution gas chromatography with high-resolution mass spectrometry (HRGC-HRMS) is used — this is one of the most sophisticated analytical techniques available and is performed by only a small number of specialised laboratories in Australia.

Management, Remediation, and Hazardous Waste Disposal

When PCB contamination is confirmed in a fire-damaged building, management must follow hazardous waste regulations. PCB-contaminated materials cannot be disposed of in standard landfill — they must be managed through licensed hazardous waste facilities capable of high-temperature incineration (above 1,100 degrees Celsius) or other approved destruction methods.

Remediation of PCB contamination typically involves removal and replacement of contaminated materials rather than in-situ treatment. The remediation contractor must hold appropriate licences for handling hazardous waste, and workers must be equipped with appropriate PPE including chemical-resistant suits and supplied-air respirators.

After remediation, independent clearance testing must verify that PCB levels have been reduced below the relevant health investigation levels. Given the extremely low guideline values for dioxins/furans, clearance testing for these compounds requires the specialised HRGC-HRMS analysis mentioned above.

If you suspect PCB contamination in a fire-damaged building — particularly any building constructed before 1986 — contact Test Australia for an independent assessment. Our Chartered Chemist qualifications and forensic science expertise ensure accurate identification and quantification of PCB contamination, with results that meet regulatory requirements and support insurance claims.