Testing Services

EMSL’s Combustion-By-Products (Char, Black Carbon/Soot, Ash) Testing Program

This test is designed for analysis of fire residues for the presence of analytes of interest (char, black carbon/soot and ash). The results of this test offers valuable information related to the extent of damage produced by soot and smoke damage. These results are commonly used for cleaning assessments and to settle insurance claims.


Surface sampling:

  • • Alcohol prep wipes (recommended surfaces: TVs, computer displays, plastic surfaces, furniture, windows, mirrors, internal surfaces of refrigerators; avoid painted surfaces)
  • • Microvacuum: 25 mm 0.45 micron or 0.8 microns pore size MCE cassettes (recommended surfaces: main living areas, from top of interior door frame, window frame, from corners of floors, door tracks, attic areas)
  • • Tape lifts (see note 1) (recommended surfaces- same as for alcohol prep wipes)

Air sampling:

  • • PVC pre-weighed cassettes (for NIOSH 5000 only)
  • • Zefon CSI cassettes (1)
  • • Zefon Air-O-Cells (1)
  • • 25 mm 0.45 micron pore size MCE cassettes

Levels of analysis

EMSL offers a diverse combination of analytical levels depending on the complexity of the methods used in the analysis and tailored to the client’s specific needs. The analysis levels are listed below, the analytical complexity level and the overall value of the package increases from level 1 to 4.

Level 1

Char + Soot(1) + Ash

Level 2

Char + Soot (confirmation level) + Ash

Level 3

Char + Soot (confirmation level) + Ash + common components of environmental dust (such as fibrous glass, biological material, cellulose, synthetic fibers, pollen, quartz, calcite)

Level 4

Char + Soot (confirmation level) + Ash + common components of environmental dust (fibrous glass, biological material, cellulose, synthetic fibers, pollen, quartz, calcite) + Elemental composition of soot, char, and ash by SEM/EDX + pH (to determine overall corrosivity of the dust)

(1): Soot analysis is limited to presumptive analysis level only; TEM analysis for confirmation per ASTM D6602 cannot be performed on tape lifts, Air-O-Cells or CSI cassette samples. In order to resolve the submicron size and the aciniform morphology of the particles, confirmatory analysis by Transmission Electron Microscopy (TEM) is needed.

Level 1 is a screening level, affordable and valuable for quick and easy assessment of the overall degree of contamination.

Levels 2, 3 and 4 offer analyses using the best analytical methods for confirmatory presence of all the analytes of interest (including soot confirmatory analysis based on ASTM D6602); the results are legally defensible.


The concentration of analytes of interest in bulk samples is derived by the Visual Estimation Technique (VAE). This technique estimates the relative projected area of a certain type of particulate in a mixture by comparison with data derived from analysis of calibration materials having similar texture and particulate content. NIOSH 5000 is a gravimetric method. Counting technique is used for Zefon and MCE air sample cassettes.

The analysis is performed by analysts trained in advanced techniques of particles identification. Additional consultation regarding interpretation of the results and regulations is provided free of charge by senior scientists. Fast turnaround times can be provided: same day and week-end analysis are available when requested. EMSL’s senior scientists have experience in litigation support and expert witness testimony.