LCS Laboratory Inc., routinely performs analysis of roofing tar for presence of coal tar. This screening test relies on tar solubility as a cost efficient way to estimate if the roofing material consists of coal tar or petroleum tar.  The ultimate proof that the material contains coal tar, is analysis for Polynuclear Aromatic Hydrocarbons (PAH) in roofing material. PAH’s are aromatic compounds with two aromatic rings (naphthalene) and more. There are several hundreds PAH’s including very complex branched molecules. EPA selected 16 PAH’s into a priority list based on their dominant presence in coal tar: 

NIHMS68764.htmlNaphthalene [91-20-3]
Acenaphthylene [208-96-8]
Acenaphthene [83-32-9]
Fluorene [86-73-7]
Phenanthrene [85-01-8]
Anthracene [120-12-7]
Fluoranthene [206-44-0]
Pyrene [129-00-0]
Benz[a]anthracene [56-55-3]
Chrysene [218-01-9]
Benzo[b]fluoranthene [205-99-2]
Benzo[k]fluoranthene [207-08-9]
Benzo[a]pyrene [50-32-8]
Dibenz[a,h]anthracene [215-58-7]
Benzo[ghi]perylene [191-24-2]
Indeno[1,2,3-cd]pyrene [193-39-5]

In this study 7 roofing tar samples that were positively identified as Coal Tar by the solubility test, were re-analysed for PAH’s using NIOSH method 5515. Method was modified for analysis of bulk tar. The samples were collected by 3 professional consultants operating in different parts of North America. Samples were taken as a part of Health and Safety protocol before starting roof repair projects.  The history of the samples is unknown, but we believe they had been exposed to sunlight and normal environmental weathering for 10 years or more.

Laboratory test reveals that all samples contain noticeable amount of PAH’s between 4% and 23% as total Polycyclic Hydrocarbons. The average concentration of individual PAH’s between 7 samples was as follows:

Average concentration of selected PAH's in roofing Coal Tar

Average concentration of selected PAH’s 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%
Crysene 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 (g,h,i) perylene 1.0%

The study proves that concentration of individual PAH’s in aged roofing tar still extremely high. Remediation of the coal tar requires extreme precaution, and implementation of vigorous safety program.   LCS Laboratory offers full laboratory support for your Coal Tar Investigation: analysis of roofing tar for coal tar presence; PAH’s in Coal Tar; PAH’s on wipe samples, PAH’s in air . To discuss the project or to order the test, please email us at your convenience