Identifying and quantifying Polynuclear Aromatic Hydrocarbons (PAHs) in roofing coal tar is critical for assessing environmental and occupational risks during roof repair projects. LCS Laboratory Inc. employs advanced analytical techniques to support the identification and safe management of coal tar in roofing materials.
Purpose of Coal Tar Analysis
Roofing tar can contain coal tar or petroleum tar. Screening tests based on tar solubility provide a cost-efficient way to estimate the composition. However, definitive identification of coal tar relies on analysing PAHs—aromatic compounds with two or more aromatic rings, such as naphthalene. The U.S. Environmental Protection Agency (EPA) has prioritized 16 PAHs commonly associated with coal tar due to their high concentrations and environmental relevance.
Technical Details of the Study
In this study, seven roofing tar samples, positively identified as coal tar through solubility tests, were analysed for PAHs using a modified NIOSH 5515 method for bulk tar. Samples were collected by professional consultants across North America as part of health and safety protocols before roof repairs. Though the exact history of the samples is unknown, they are believed to have been exposed to sunlight and environmental weathering for over a decade.
Laboratory analysis revealed PAH concentrations ranging from 4% to 23% of total polycyclic hydrocarbons in the samples. The average concentrations of individual PAHs across the seven samples were as follows:
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The average concentration of selected PAHs in roofing Coal Tar
Naphthalene: 0.2%
- Acenaphthylene: 0.1%
- Acenaphthene: 0.2%
- Fluorene: 0.2%
- Phenanthrene: 1.6%
- Anthracene: 0.5%
- Fluoranthene: 1.7%
- Pyrene: 1.2%
- Benzo[a]anthracene: 0.7%
- Chrysene: 0.7%
- Benzo[b]fluoranthene: 1.1%
- Benzo[k]fluoranthene: 0.4%
- Benzo[a]pyrene: 1.3%
- Indeno[1,2,3-cd]pyrene: 1.1%
- Dibenz[a,h]anthracene: 0.1%
- Benzo[ghi]perylene: 1.0%
The findings demonstrate that even aged roofing coal tar contains significant concentrations of PAHs, posing substantial health and environmental risks.
Implications for Safety and Remediation
The high PAH concentrations in aged coal tar highlight the need for stringent safety measures during remediation. Proper precautions, including detailed risk assessments and robust safety programs, are essential to protect workers and the environment.
How LCS Laboratory Can Help
LCS Laboratory Inc. provides comprehensive laboratory support for coal tar investigations, including:
- Analysis of roofing tar for coal tar identification.
- Quantification of PAHs in coal tar.
- Analysis of PAHs in wipe and air samples.
For more information or to discuss your project, please email us. Our team is ready to assist with all your analytical needs.
