Respiratory Protection of Firefighters: Live-fire Assessment of CBRN Canisters during Firefighter Overhaul
Funded by Centers for Disease Control and Prevention, Grant No. 211-2015-62973
Study Partners
Northwest Fire Department (Tucson, AZ),
Yuma Fire Department (Yuma, AZ),
Purpose
Firefighters are at increased risk of developing cancer, possibly due to carcinogen exposure on the fire ground and during overhaul. Until recently, it was common practice to remove respiratory protection during overhaul activities. The use of self-contained breathing apparatus (SCBA) equipment during overhaul is common in some fire departments, but this has not yet become common practice in fire departments nationwide.
The current study aims to identify contaminants in the overhaul environment in both live-fire and simulated fire overhaul environments. Additionally, we will analyze the effectiveness of the SCBA and compare it against the effectiveness of a chemical, biological, radiological, nuclear CBRN filtration canister to determine if the CBRN canister and full-face respirator is a safe alternative for firefighters in overhaul.
From this we hope to gain a better understanding of the exposures firefighters are encountering in overhaul environments. In addition, we hope to determine if CBRN canisters are effective at preventing hazardous respiratory exposures in the overhaul environment. If so, we are hopeful that having the additional option to use CBRN canisters and full-face respirators will encourage fire departments to require respiratory protection during overhaul.
Aim #1:
Collect samples at 5 live fires and 15 simulated fires to determine the potential exposures firefighters are encountering when in overhaul.
Aim #2:
Determine the effectiveness of a CBRN canister to filter the contaminants in the overhaul environment.
- Compare in-mask SCBA samples to in-mask CBRN samples collected in the overhaul environment to assess the efficiency of the CBRN filter to the SCBA.
- Compare both samples to the overhaul environment samples collected in the overhaul environment.
Methods
Study Design and Sampling
- The University of Arizona (UA) breathing cart (pictured below) is equipped with two masked manikin heads connected to a Dynamic Breathing Machine. Each manikin head will wear one of the two types of respiratory protection, either SCBA or CBRN. While the breathing cart is operating in the overhaul environment, samples will be collected in each mask, from the ambient air and from the breathing zone of the firefighter.
- UA researchers will attend fires that Northwest Fire District (NWFD) is dispatched to. After the fire has been extinguished and the overhaul phase has begun, UA researchers will place the breathing cart in the overhaul setting for 20 minutes. At the same time, UA researchers will place sampling equipment on a firefighter that is participating in overhaul. At the end of the 20 minutes, the cart will be removed. Samples will be sent to an accredited lab and analyzed for concentrations of specific aldehydes, inorganic acid, polynuclear aromatic hydrocarbons, aromatic hydrocarbons, particulates, and nitrogen dioxide.
- UA researchers will complete 15 simulated fires using common household materials over two days with the Yuma Fire Department at the Yuma Fire Department Training Center. At the end of each burn, UA researchers will place the breathing cart in the overhaul environment for 20 minutes while a firefighter wearing the sampling equipment simulates overhaul activities. At the end of the 20 minutes, the cart will be removed. Samples will be sent to an accredited lab and analyzed for concentrations of specific aldehydes, inorganic acid, polynuclear aromatic hydrocarbons, aromatic hydrocarbons, particulates, and nitrogen dioxide.
- Samples taken from the overhaul environment will be compared to those taken in each mask to determine the effectiveness of the respiratory protection used on each manikin head. Samples collected from the breathing zone of the firefighter will be used to characterize the environment the firefighter comes in contact with while in overhaul.
Assessment of DPM Exposure in Firehouses and Potential Controls to Reduce Exposures
Funded by: Northwest Fire District (Tucson, AZ) and FEMA
Study Partners
Northwest Fire District
Purpose
Firefighters have an increased risk of cancer relative to the general population. Though firefighters wear self-contained breathing apparatus (SCBA) to protect themselves from smoke while at the scene of a fire, they remain exposed to other hazards such as diesel particulate matter (DPM) when they are not on scene. This DPM exposure is concerning as it is known to cause cancer in humans.
Diesel engines are the standard for fire engines and produce DPM when fuel is not burned at a high enough temperature. DPM exposure was evaluated in stations operated by two Tucson area fire departments and in nine volunteer stations nationwide. Samples were collected in the living quarters, the truck bays, and in outside (ambient) conditions at each station.
Firefighters, while in the station, are being exposed to low levels of DPM that are higher than normal conditions. Poor station ventilation was identified frequently and is believed to be the reason for DPM contamination in the apparatus bays and living quarters. Due to the cost, rather than sampling for DPM, fire departments should evaluate local exhaust ventilation and heating, ventilation and air conditioning (HVAC) systems and redesign/repair systems that cause DPM to remain in apparatus bays and in living quarters.
Study Design and Sampling
- DPM samples were collected every minute for a 24-hour period in the living quarters, truck bays and outside air in a total of 28 stations.
- Samples were compared to determine if the concentrations were higher in the station apparatus bay and/or living quarters than in outside conditions.
Recommendations
- Assume that there is at least a low level of DPM in the facility and take action to protect against it.
- Have all HVAC systems professionally evaluated to check that they are operating within their design specifications.
- Ensure that all fresh air intakes are not located near ventilation exhausts.
- Purchase cleaner burning vehicles whenever possible.
- Make sure the living quarters is under positive pressure relative to the apparatus bay.
- Keep doors that lead from the truck bays to the living quarters closed.