Biologic hazards may come from human and/or animal bodies, poisonous plants, bugs and animal bites. These hazards can usually be mitigated by the effective use of proper personal protective equipment (PPE). While these conditions must be considered during the scene safety assessment, they are either present or they are not. Toxic hazards on the other hand are present at every fire scene. The primary toxic hazards are from the many gases contained in fire smoke and fire debris. Fire smoke consists of invisible vapors and visible particulates, and both are hazardous to the fire investigator. Fire debris contains many different chemicals, gases and particulates that are hazardous. During and immediately after a fire there are many fire gases present. But after the fire, and often for a considerable time, there are particulates, vapors and gases present that can be a threat to the fire investigator. While much has been written in the last ten years about the effects of these toxic gases on firefighters, not enough has been said about their effects on fire investigators.
There have been a number of studies involving firefighters during structural firefighting and overhaul operations in Sweden, the United Kingdom, New Zealand, the United States and Canada that all indicate the need for atmospheric monitoring and SCBA use during salvage and overhaul. The results of these studies are very relevant to fire investigators because they tell us that toxic gases may well be present at their fire scenes, even several days after the fire in some cases, and that air monitoring needs to be conducted and appropriate respiratory protection needs to be used.
The first documented research relating to fire investigators was the NIOSH/ATF study in 1996-97 that studied actual fires & test burns. They found that fire investigator exposures to irritants that cause acute effects and carcinogens that have chronic effects are of concern and that the use of respiratory protection and mechanical ventilation equipment can reduce the potential for exposure.
A 2010 survey of 70 fire investigators attending an IAAI Arizona chapter seminar found that nearly 50% of the investigators did not routinely use any type of respiratory protection. As a follow-up to this survey, in 2011 a Phoenix FD fire investigator using a four-gas meter and two sampling pumps that tested for O2, CO, HS, HCN and broad-spectrum aldehydes took air samples while conducting investigations at 16 fire scenes. Eight fires contained detectable levels of airborne hazardous toxins and three of those fires approached or exceeded the ceiling limit exposure levels. Ventilation appeared to be the most significant factor in influencing the amount of airborne hazardous toxins that remained in the fire scene after overhaul. Time, by itself, however, was not a good predictor of possible hazards. In one instance high levels of formaldehyde were found at a scene three days after fire. Other findings included:
The size of the fire was not a good indicator of the potential hazards
The size of the fire in relation to the structure was not a good predictor of possible hazards
A small kitchen fire produced the highest readings
Many factors affect results:
o Amount and type of ventilation
o Size/location of fire
o Type of structure
Ventilation may help with gases but may not with particulates
There have been several other studies conducted with similar results.
The cumulative results of all this research tell us that:
Fire investigators generally are at more fire scenes than most firefighters
More particulates are present during and after overhaul
Fire investigators generally wear less PPE than firefighters
Fire investigators have a high exposure risk to toxic hazards
While we are seeing more SCBA use by firefighters during overhaul, investigators are generally not properly using respiratory protection
What does all of this mean for fire investigators? Investigator welfare and safety needs to be a higher priority than it is in many agencies. We need to be proactive by knowing and following the applicable SOPs and local, state and federal regulations; wearing the proper PPE, including respiratory protection, at all times while at fire scenes; knowing the warning signs of acute toxicity and ensuring that atmospheric monitoring for CO and HCN is conducted during all fire scene examinations. We can no longer afford to just assume that a scene is safe; we must know the conditions before we enter and include atmospheric testing with all of the other considerations made during the initial scene safety assessment. But low readings do not mean that the atmosphere is completely safe.
Today’s fire scene is vastly different than that of twenty or more years ago and it is getting more hazardous as the use of man-made materials increases. Even though we crawl around in and dig up debris that contains particulates and can release toxic gases, or the gases just ride along on the particulates on their trip into your unprotected lungs, the culture of the past has been, “It hasn’t hurt me yet so why should I change?” or “That’s the way we’ve always done it” or even worse, “It isn’t manly to wear all that stuff.” Unfortunately this old school mentality is exacerbated by the fact that, absent something bad happening at or immediately after being at a scene (acute symptoms), we go home feeling pretty OK and not thinking about the cumulative or chronic effects of these exposures so when medical issues do develop in later years it is too late to go back and change things. This is an inherently dangerous attitude that needs to change. Establishing, following and enforcing scene safety protocols today will save fire investigator’s
lives in the future. The number one way to accomplish this is through the proper use of PPE, especially respiratory protection.
