Fire & Smoke Investigations


One of the most difficult challenges in cleaning up after a fire is determining the level of remaining fire and smoke residue.  We typically are aware of these residues as visual traces (e.g., soot, char, or ash on surfaces), smoky odors, or health effects (e.g., burning eyes, difficulty breathing, etc.).  There are two primary concerns with fire and smoke residue:

  1. Has the fire or smoke residue been removed to an acceptable level?

  2. Are there any health or exposure concerns with any remaining traces?


Fire produces a complicated mixture of particulates (soot, ash, and char) and chemicals that makes a comprehensive analysis challenging.  By combining analyses of these major components a far better and more inclusive picture of the residues can be accomplished.

There are two primary fire situations, indoor or structure fires and wild fires.  Indoor fires are complicated by the contents and building materials, as well as the level and strength of the fire.  Wild fire smoke can travel long distances and impact buildings miles away from the main fire.

In addition to the fire and smoke residue, mold is often a concern in post-fire situations because the water or other fire-fighting measures used creates excess moisture that mold can use to grow.

For assistance with planning your upcoming project or to learn more about fire and smoke residue testing, contact us at or 989-772-5088.

Air Sampling

One of the most noticeable after effects of a fire is the smoky odor.  This is caused by certain chemicals in the air that are given off by burned materials or by non-burned materials that have adsorbed these chemicals and are re-emitting them slowly over time.  There are other chemicals without a noticeable odor that are also produced as a result of a fire that are also present in the air that can be detected with an air sample.

Material Sampling

During cleanup or remediation most of the lighter chemicals will dissipate due to normal ventilation or as part of the remediation, but the more persistent chemicals, which are also the heavier or less volatile chemicals, can linger for months or even years.  Since these persistent chemicals are not very volatile they will often condense out of the air or be adsorbed by various materials.  In these cases, an analysis of materials that were near the fire or smoke (e.g., furniture upholstery or padding, carpet, drywall, dust, etc.) may be the best way to determine if residual contamination is still present.


Fire and smoke produce a complex mixture of chemicals.  Because of this complexity, it is not sufficient to simply perform a chemical analysis of fire, that analysis must also be placed into context with chemicals produced by other sources.  This drives the use of specific chemical indicators that are relatively unique (i.e., have few other sources) and yet are common to multiple fire types or conditions to stand in for all the other chemicals produced by the fire.

Particulate Sampling

Microscopy analysis of the size, shape, and chemical composition of dust or particulate residue leading to the identification of  soot, ash, and char has long been the standard in fire residue analysis.  This type of analysis is also complicated by the variety of fire conditions and secondary sources, making definitive evaluation of fire residue by this method alone challenging.  Dan Baxter of Environmental Analysis Associates (EAA) has pioneered the development of innovative tools to enhance this process and, together with the chemical analysis provided by Prism, produced a more comprehensive and useful process of assessing the level of fire and smoke contamination.