Toxicology Consultants & Assessment Specialists, LLC

Hazardous Substances

TCAS provides toxicological assessment services for a wide range of hazardous substances
TCAS provides toxicological assessment services for a wide range of hazardous substances[a]

Hazardous substances constitute a special class of toxic agents in that they pose immediate dangers to human health via simple contact or proximity. TCAS provides toxicological consulting and assessment services for a wide range of hazardous toxic substances, including environmental hazards, industrial chemicals, hydrocarbons, petroleum products, heavy metals and compounds, dioxins, pesticides and many others.

TCAS routinely collects and evaluates site data, compiles geophysical data and historical information, identifies substances present at a site and produces exposure assessments on behalf of clients. Such assessments establish toxic exposure pathways, quantify toxicity with respect to adverse health effects associated with exposures and provide reasonable estimates with respect to current and future land-use assumptions.

Hazardous Substance Toxicological Reference

This section summarizes some of the substances for which TCAS has regularly performed toxicological assessments, produced written reports and/or provided expert testimony subsequent to being retained by defendants, plaintiffs, prosecutors, state attorney generals, public defenders' offices and U.S. Attorneys' offices.

For purposes of quick reference, hazardous substances can be divided into five basic groups: (1) Environmental Hazards, (2) Industrial Chemicals, (3) Hydrocarbons, (4) Metals & Compounds and (5) Pesticides. Collectively, these groups represent a universe of toxic synthetic and biological agents. As it is impossible to summarize them all within the scope of this website, the table below presents an abbreviated list of some hazardous substances for which TCAS has regularly produced toxicological assessments and provided expert opinions and testimony over a period of more than 34 years.

Click on any substance to view the corresponding entry.


  1. Montage of public domain thumbnail images: International Association of Fire Chiefs, Woods Hole Oceanographic Institute, et al.

A Message from Dr. William R. Sawyer
Chief Toxicologist, TCAS, LLC

A message from Dr. William R. Sawyer, Expert Toxicologist

Hazardous substance toxicology requires application of scrupulous attention to detail and methodology. Many years of experience are a virtue in conducting such assessments, particularly in cases involving widespread contamination.

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This is an informational and instructional website devoted to toxicology. It presents both original and edited public-domain content compiled as a useful educational resource. References and footnotes have been included wherever possible and image sources have been cited where appropriate. Although most pages can be printed or downloaded as PDF files (and we encourage you to make constructive use of our information), this website is copyrighted and material may only be reproduced and/or distributed with prior permission from TCAS, LLC.