NIOSH Recommends Controls for Diesel Exhaust in Fire Station
A recently published health hazard evaluation (HHE) report describes a NIOSH assessment of diesel exhaust exposures to personnel in a city fire station (PDF). Air concentrations of carbon monoxide, carbon dioxide, and diesel particulate matter in the apparatus bay and personnel living quarters were well below relevant occupational exposure limits, NIOSH found. Levels of ultrafine particulate matter at this fire station were also much lower than those measured during HHEs of two other local stations, which the report attributes to this station’s use of vehicle exhaust filters. But since diesel exhaust is a carcinogen that may cause eye, nose, throat, and lung irritation, especially in people with asthma, NIOSH recommends improving ventilation at the fire station, as well as addressing other health and safety issues.
At the request of fire department management, NIOSH visited this fire station in August 2024 and July 2025 to observe work processes and practices; collect area air samples of diesel particulate; measure concentrations of carbon monoxide, carbon dioxide, and particulates in areas throughout the station; measure particulate concentrations at the vehicles’ tailpipes when the engines were running; and assess the station’s ventilation. The report notes that all the station’s diesel-powered vehicles built after 2007 had ceramic diesel particulate filters installed directly on their mufflers, while the fire engine built in 2003 was equipped with an older model engine exhaust filter. Both systems require regular cleaning.
“Because there is no known safe level for most cancer-causing hazards, it is important to reduce exposures [to diesel exhaust] to as low as possible,” the report states.
NIOSH recommends that fire station personnel reduce diesel exhaust exposures by closing apparatus bay doors when vehicles are idling outside and opening the doors when engines are running inside the bays, such as during morning equipment checks. Firefighters should also be trained to correctly use and maintain engine exhaust filters.
The evaluation found that air in the station flowed from personnel living quarters into the apparatus bay, the preferred setup for lowering crew exposures to diesel exhaust. But air from the turnout gear room sometimes flowed into the living quarters, a setup that may increase exposures from off-gassing gear. NIOSH recommended that fire station personnel coordinate air supply and exhaust to maintain negative pressure in the turnout gear room.
The report also recommends addressing two other health and safety issues identified during the evaluation. First, NIOSH investigators saw that the filters in the air handling unit of the station’s energy recovery filter were folded, potentially allowing air to bypass them, so the report suggests installing vertical support bars to the filter holder. Agency staff also urge fire station personnel to store flammable liquids inside the designated safety cabinet when not in use.
The HHE report on diesel exhaust controls at a municipal fire station (PDF) may be downloaded from the NIOSH website.