# Oxygen Regulator Flash Severely Burns One Fire Fighter - Florida/Investigation

​ INVESTIGATION
On June 12, 1998, at approximately 0730 hours, the victim arrived at his assigned station (Station 17) and prepared to start his 0800 hour shift. Arriving early, the victim decided to perform an equipment check on the Engine to which he was assigned as two additional fire fighters finished their shift by washing the Engine with a garden hose. As the victim sorted through the Engine’s equipment compartments, he opened the airway equipment compartment, removed the airway bag, and prepared to perform a routine pressure check. The airway bag consisted of an aluminum cylinder filled with 99.7% pure oxygen, an aluminum regulator attached to the cylinder, and airway supplies (Photo 1). To charge the cylinder and check its oxygen pressure, the victim set the cylinder upright, from a horizontal to vertical position. As he opened the cylinder post valve, the cylinder emitted a loud popping sound and then flashed, releasing two 4-foot flames, one toward the victim and the other toward the Engine (Photo 2). The victim turned, pushing the cylinder away, and fell to the ground with his clothes ignited from the waist up. One of the fire fighters, who was washing the other side of the Engine, stated that he heard a noise which sounded like one of the brake lines had burst. As he leaned under the Engine to check the lines, he saw the victim fall to the ground surrounded by flames. The other fire fighter washing the Engine stated that he watched the victim open the cylinder valve and heard the cylinder emit a loud pop and then flash, releasing two 4-foot flames, one toward the victim and the other toward the Engine. The fire fighter who witnessed the incident called for the other fire fighter washing the Engine to bring the hose he was using around to the victim. The fire fighter stretched the garden hose around the Engine, and spraying water on the victim, extinguished the flames approximately 10 seconds after the cylinder flashed. The fire fighter then turned the hose on the cylinder, which was emitting a loud whistling sound. The cylinder continued to burn for approximately 30 to 40 seconds before the fire was completely extinguished. The fire fighter turned the hose back on the victim, trying to cool him down as the on-duty medical personnel provided assistance. They removed his shirt and wrapped him in a burn blanket, and approximately 2 to 3 minutes later, he was placed in a rescue vehicle. A fire fighter/medic who had just arrived to start his shift saw the commotion, and proceeded to the rescue vehicle. The medic entered the rescue vehicle and took over medical responsibilities. The medic stated that en route to the local trauma center, they secured the victim’s airway, started intravenous fluids, and flushed his eyes. During transport, the medics reported that the victim had approximately 35 to 40 percent first-, second-, and third-degree burns. The victim was later air-lifted to an area burn center.
NIOSH investigators visited the oxygen cylinder refilling stations located at Stations 34 and 28. The cylinder involved in the incident was filled at Station 28, where the filling station is separate from all other activity, and the environment is air conditioned, organized, and clean. This filling station is kept locked when not in use. The filling station at Station 34, however, is housed in the station’s bay along with the trucks and equipment. The bay is not air conditioned. After the incident, for additional safety at Station 28, the fire department installed a steel cage with a steel rolling door to enclose the cylinders while they are being filled. NIOSH investigators also reviewed the logs in which the station recorded information about filling the cylinders with oxygen, and the logs appeared to be up-to-date and sufficient. The records indicated that on the 12th of June, a Captain from the fire department, along with a representative from an independent medical service, checked the oxygen quality at both ​filling Stations 34 and 28. At Station 28, the readings were taken with an oxygen analyzer supplied by the independent medical service while at Station 34 the readings were taken with the station’s oxygen analyzer. The oxygen purity readings for both stations were 99.7% pure oxygen. Random samples taken from cylinders in the field also proved sufficient.
The fire fighters involved in the process of filling cylinders with oxygen are trained in the proper procedures. The oxygen cylinders commonly filled by the fire department and used as medical equipment by the paramedics and EMTs are D- and E-size cylinders (Photo 3). These cylinders are filled from a cascade system of 12 M-size (300-cubic-ft.) cylinders connected in series (Photo 4). The cascade systems used at Station 34 and 28 are capable of refilling 14 D- or E-size oxygen cylinders at a time. Two banks of 7 cylinders each are arranged in a storage rack for filling (Photo 5). As cylinders are refilled, 1 out of every 14 is sampled to ensure the cylinder is filled with 99.7% pure oxygen. If a sample is found to fall below 99.7%, the entire lot of 14 is isolated until the problem is identified and corrected. After filling, each cylinder is capped with a plastic plug over the post valve opening to keep the valve clean and to identify cylinders that are ready for use.
The fire department’s standard procedure requires at least 300 psi of pressure to remain in the cylinders awaiting to be filled. If cylinder pressure is less than 300 psi, the cylinder is taken out of service, flushed with nitrogen using compressed nitrogen from a size M cylinder and a Model DOA-V192-AA gas pump, and returned to the vender for hydrostatic testing and inspection. Standard procedures also require the cascade operator to check the hydrostatic date of each cylinder before it is refilled. Steel and aluminum cylinders must be inspected and hydrostatically retested every 5 years per U.S. Department of Transportation regulation Title 49, Code of Federal Regulation (CFR) Part 173.34 (e).
A representative from the fire department stated that the oxygen resuscitator involved in the incident was pressure checked by a fire fighter on the earlier shift, and the resuscitator appeared to be working properly. The department also stated that the oxygen resuscitator was not used for patient care during the shift prior to the incident.
The representative from the fire department stated that it had previously experienced an incident with an oxygen cylinder and regulator of the same type involved in this investigation. Although the incident did not cause serious injury, the fire department replaced all of its cylinder regulators with a different model from a new manufacturer. After the regulators were changed out, the fire department received a notice from the manufacturer of the previous regulators stating that the regulator had been associated with fire in six incidents reported over the past 3 years. The manufacturer notice indicated that a retrofit kit would be forwarded to the fire department upon request. The retrofit kit included a bronze sintered-inlet filter, a new warning label, an allen wrench, and an instruction sheet necessary to retrofit the existing regulator. The fire department’s previously used regulators were listed in the notice so the fire department notified the manufacturer, who supplied the department with retrofit kits for all of the previous regulators. The fire department retrofitted all of it’s regulators but did not put them back into service. Even though these regulators were not put back into service, the regulator involved in the incident (which was retrofitted) was mistakenly placed into service during a maintenance changeover.
In addition to the replacement parts, the retrofit kit contained a warning sticker that was to be placed on each regulator as soon as it had been retrofitted (Photo 6). The sticker read: WARNING: 1. The introduction of contaminates and hydrocarbon substances into the regulator may cause combustion; 2. Open the cylinder post valve slowly. The sudden inrush of oxygen into the regulator may cause combustion if contaminates are present. The sticker served not only as a warning but also as an identifier to indicate regulators that had been retrofitted. A retrofit sticker had been placed on the regulator involved in this incident. After the incident, the fire department sent the cylinder and regulator involved in the incident to an independent testing laboratory for further testing. Oxygen resuscitators are medical devices which come under the jurisdiction of the Food and Drug Administration (FDA). NIOSH has been working with the FDA on the issues identified through the NIOSH investigation. The FDA recently issued a Public Health Advisory jointly with NIOSH entitled Explosions and Fires in Aluminum Oxygen Regulators. A copy of this advisory is available on the FDA homepage at: www.fda.gov/cdrh/safety.html.