Following a fire event, a variety of people spend considerable time in the post-fire environment. In addition to first responders, fire and law enforcement, the individuals performing investigations in the property can include insurance claims adjusters, origin and cause fire investigators, inventory assessors, and damage assessors. The fire service, EMS and law enforcement may typically be assumed to be wearing appropriate personal protective equipment (PPE), but exposure to post fire hazards should be considered for those entering the property and performing work well after the fire event.
Many exposure hazards can exist in a post fire setting independent of the property's age. Gasses, vapors and chemical hazards may be present in levels that can cause adverse health effects. Additionally, suspended particulates may include polycyclic aromatic hydrocarbons (PAHs), asbestos and other hazardous materials. These hazards are not necessarily limited to the immediate area of the fire, as particulates can remain airborne for long periods of time and be re-entrained in the air with any air movement.
To lower the risks to those entering properties after a fire event, the following should be considered as part of the planning processes in assigning or performing field adjusting, contents inventory, fire origin and cause investigations, and engineering or environmental assessments:
- While direct exposure to inhalation hazards can be minimized through the use of respiratory protection, be sure to use filters for both particulate (HEPA filters) and volatile organic compounds (charcoal charged filters). Generally these "dual cartridge" respirator filters are color coded with dual colors: with magenta (for particulate) and yellow (for chemical hazards). Also be reminded of potential breathing restrictions and increased potential for heat stress on a warm day. Leave sufficient time to remove yourself from the building, hydrate and recharge before continuing with your work.
- During application, many building products 'off-gas' at various rates based upon the product and chemical composition. Some products require significant ventilation when applied due to their high volatility (glues, mastics, foams) while others a more gradual curing process (consider wall paint). Once burned, these chemicals are released back into the air, generally all at the same time. Be sure there is adequate ventilation throughout your inspection areas.
- Garments repeatedly used for these types of investigations can contribute to secondary exposures to these chemicals or hazardous particulate. In cold weather, hardhat liners, gloves, boots, and jackets all are exposed to the post fire environment and may not be under coveralls. Routinely replace these items.
- Decontamination of equipment, no matter how small, should be performed to avoid another route of secondary exposure. Investigators tools of choice should be kept separate from non-fire scene equipment, be enclosed/encased to provide separation from vehicle interiors (and the ventilation system of the vehicle).
- Consider the potential for hazardous materials on evidence removed from a fire scene. An open air cleaning of the evidence, if possible, will limit the potential for secondary exposures of others in the investigation chain (materials laboratories, other investigators, etc.). Of course spoliation of evidence concerns must also be considered in the handling of this decontamination process.
- Real time reading instrumentation is useful, but understand that a multi-gas detector does not measure dust and dust detectors don't measure volatiles.
- Don't assume a "newer" property is free from asbestos containing building materials (ACBMs). There is no definitive date where ACBMs will not be found and assumptions on post-1982, post 1985, post-1990 may not be prudent. Some field observations:
- Don't limit your concern of asbestos contaminants to "friable" materials only. Many non-friable materials such as floor tiles, cement board, and mastics, when burned, exhibit the same properties as friable materials: they can be pulverized under hand pressure and release asbestos fibers.
- "Renovations": Layered, older material can be present behind newer finishes. Examples include felt paper liners in subflooring, glues and mastics under carpeting or newer floor tiles, older wallboard/plaster behind reconfigurations of a new floor plan.
- Asbestos-containing Wallboard joint compound is not just present at joints or corners. Consider the application uses 6 to 18 inch trowels to feather the product and make the wall joints indistinguishable.
- Consider how binders and additives were mixed on site for building products such as textured wall or ceilings, joint compound, glues and mastics for flooring, ceilings or decorative fixtures. Some of these additives contained asbestos for thermal and binding properties and could have been stored on site or stockpiled elsewhere for future use.
Keith Pokorny, LEED AP, Vice President of Environmental Services, has more than 25 years of experience in Environmental, Engineering, and Construction Management services. He specializes in large project coordination and assists clients in implementing construction-related capital improvement programs.
©Copyright - All Rights Reserved
DO NOT REPRODUCE WITHOUT WRITTEN PERMISSION BY AUTHOR.