U.S. Fire Administration/Technical Report Series

Special Report:

Fires Involving Medical

Oxygen Equipment

USFA-TR-107/March 1999

U.S. Fire Administration Fire Investigations Program

T

he U.S. Fire Administration develops reports on selected major fires throughout the country. 

The fires usually involve multiple deaths or a large loss of property. But the primary criterion 

for deciding to do a report is whether it will result in significant “lessons learned.” In some 

cases these lessons bring to light new knowledge about fire--the effect of building construction or 

contents, human behavior in fire, etc. In other cases, the lessons are not new but are serious enough 

to highlight once again, with yet another fire tragedy report. In some cases, special reports are developed to discuss events, drills, or new technologies which are of interest to the fire service.

The reports are sent to fire magazines and are distributed at National and Regional fire meetings. The 

International Association of Fire Chiefs assists the USFA in disseminating the findings throughout the 

fire service. On a continuing basis the reports are available on request from the USFA; announcements of their availability are published widely in fire journals and newsletters.

This body of work provides detailed information on the nature of the fire problem for policymakers 

who must decide on allocations of resources between fire and other pressing problems, and within 

the fire service to improve codes and code enforcement, training, public fire education, building 

technology, and other related areas.

The Fire Administration, which has no regulatory authority, sends an experienced fire investigator 

into a community after a major incident only after having conferred with the local fire authorities 

to insure that the assistance and presence of the USFA would be supportive and would in no way 

interfere with any review of the incident they are themselves conducting. The intent is not to arrive 

during the event or even immediately after, but rather after the dust settles, so that a complete and 

objective review of all the important aspects of the incident can be made. Local authorities review 

the USFA’s report while it is in draft. The USFA investigator or team is available to local authorities 

should they wish to request technical assistance for their own investigation.

This report and its recommendations were developed by USFA staff and by Varley-Campbell & 

Associates, Inc. Miami and Chicago, its staff and consultants, who are under contract to assist the Fire 

Administration in carrying out the Fire Reports Program.

The U.S. Fire Administration greatly appreciates the cooperation received from Chief Tim McGrath 

and Chief Fred Friedl, III of the Gurnee Fire Department; Chief Bill Martin of the Union Colony 

Fire/Rescue Authority; Captain Kent Berg of the Greenville County Emergency Medial Service; David 

Wuertz of the Austin Emergency Medical Services; Chief Gerald Hammernik of the Oak Creek Fire 

Department; John Gillenwater of the Truckee Meadows Fire Protection District; Chief Steve Roehl of 

the Springfield Department of Fire and Life Safety; and the Compressed Gas Association.

For additional copies of this report write to the U.S. Fire Administration, 16825 South Seton Avenue, 

Emmitsburg, Maryland 21727. The report is available on the Administration’s Web site at http://

www.usfa.dhs.gov/

Special Report:

Fire Involving Medical

Oxygen Equipment

Investigated by: Thomas H. Miller, P.E.

This is Report 107 of the Major Fires Investigation Project conducted 

by Varley-Campbell and Associates, Inc./TriData Corporation under 

contract EME-97-CO-0506 to the United States Fire Administration, 

Federal Emergency Management Agency.

Department of Homeland Security

United States Fire Administration

National Fire Data Center

U.S. Fire Administration

Mission Statement

As an entity of the Department of Homeland 

Security, the mission of the USFA is to reduce life and economic losses due to fire 

and related emergencies, through leadership, advocacy, coordination, and support. 

We serve the Nation independently, in coordination with other Federal agencies, 

and in partnership with fire protection and 

emergency service communities. With a 

commitment to excellence, we provide public education, training, technology, and data 

initiatives.

AcknOwlEdgMEntS

The United States Fire Administration appreciates the help of the following persons that provided 

information for this report:

Fred Friedl, III Chief, Gurnee Fire Department, Gurnee, Illinois

Bill Martin Chief, Union Colony Fire/Rescue Authority, Greeley, Colorado

David Wuertz Austin Emergency Medical Service, Austin, Texas

Kent Berg Captain, Greenville County Emergency Medical Service, Greenville, 

South Carolina

Gerard Hammernik Chief, Oak Creek Fire Department, Oak Creek, Wisconsin

John Gillenwater Truckee Meadows Fire Protection District, Reno, Nevada

Steve Roehl Chief, Department of Fire & Life Safety, Springfield, Oregon

Dr. Michael J. Jule, Director of Genesee Emergency Services, Grand Blanc, Michigan

DO, FACEP

Charles Henrici Chief, River Forest Fire Department, River Forest, Illinois

Matthew Cole, P.E. U.S. Department of Energy, Germantown, Maryland

Frank Washenitz, II National Institute for Occupational Safety & Health, Morgantown, 

West Virginia

Ta

OVERVIEW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

KEY ISSUES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

HAZARDS OF OXYGEN-ENRICHED ATMOSPHERES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

SPECIAL HAZARDS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

INCIDENT DESCRIPTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Department of Fire & Life Safety, Springfield, Oregon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Union Colony Fire/Rescue Authority, Greeley, Colorado. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Austin Fire Department, Austin Emergency Medical Services, Austin, Texas. . . . . . . . . . . . . . . . 7

Houston Fire Department, Houston, Texas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Gurnee Fire Department, Gurnee, Illinois. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Broward County Fire/Rescue, Broward County, Florida. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Greenville County Emergency Medical Service, Greenville, South Carolina. . . . . . . . . . . . . . . 13

Oak Creek Fire Department, Oak Creek, Wisconsin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Truckee Meadows Fire Protection District, Reno, Nevada. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Additional Incidents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

OXYGEN REGULATOR RECALL AND SAFETY NOTICE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

MAINTENANCE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

CONTRIBUTING FACTORS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

LESSONS LEARNED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

APPENDIX A: Additional Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

APPENDIX B: Compressed Gas Association Bulletins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

APPENDIX C: Recall Notice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1

OVERVIEw

The United States Fire Administration has noted with growing concern the number of flash fire incidents linked to lightweight, portable oxygen equipment. The following report describes the general 

hazards associated with oxygen-enriched atmospheres, including aluminum in contact with highpressure oxygen, a number of recent incidents, maintenance recommendations, and contributing 

factors are also included.

The United States Food and Drug Administration (USFDA) has received 16 reports of flash fire incidents from 1993 to 1999. Each incident involved portable oxygen cylinders and combination pressure and flow regulators. Collectively, those incidents caused severe burns to 11 health care workers, 

emergency medial service providers, firefighters, and patients.

The typical applications of the equipment involved were ambulance/emergency jump bags. The incidents involved patient transfers both within and to health care facilities, and in some cases, people 

receiving continuous oxygen therapy which they carried with them. The combination pressure and 

flow regulators involved in the 16 fire incidents were constructed of aluminum and the aluminum 

was exposed to pure oxygen in the regulator’s high-pressure section. The regulators were attached 

to “D” or “E” sizes high-pressure oxygen cylinders. Where oxygen cylinder construction was identified, aluminum cylinders were involved more often than steel. However, the recommendations, 

precautions, and procedures in this report apply regardless of the regulator’s or cylinder’s construction material.

This report contains information on ten flash fire incidents that involved either fire service or emergency medical service personnel. No attempt was made to analyze experience from the other application. The incidents resulted in serious injuries to emergency personnel and property damage, 

including the loss of two ambulances and considerable destruction to a fire station. Patient treatment 

was affected in some incidents as the newly injured had to be attended to and additional equipment 

and service providers placed into service.

Allied Healthcare Products estimated that between one-quarter million to one million combination pressure and 

flow regulators are currently in service in the United States. It is not clear how many of these regulators are 

constructed of aluminum versus other metals such as brass. While all of the ten incidents addressed 

in this report involved aluminum-bodied regulators, fires involving contaminated brass-bodied 

regulators on larger “H” size medical oxygen cylinders have also occurred. The type of metal that 

the regulator is constructed of does not eliminate the fire hazard associated with pure oxygen, especially 

when it is under high pressure. However, brass is substantially less likely to ignite than aluminum 

under the same conditions because it does not react as energetically with high-pressure oxygen.

Special Report:

Fire Involving Medical

Oxygen Equipment

March 1999
2 U.S. Fire Administration/Technical Report Series

K

Issues Comments

Pressure Regulator Construction 

Material

Aluminum and many aluminum alloys are susceptible to ignition in standard test in pure 

oxygen at pressures as low as 25 psi. Brass and metals rich in copper are much more 

resistant to ignition even at oxygen pressures above 8,000 psi.

Change in Material Flammability Enriched oxygen atmospheres will change a material’s flammability and ease of ignition. 

Most materials, including those considered noncombustible in air, can be ignited and will 

burn vigorously in an oxygen rich environment.

Contamination While oxygen is a nonflammable gas, it enhances the ignition and combustion of many 

materials. Oxygen can react with contaminants resulting in a flash fire.

Heat of Compression As the oxygen cylinder is opened, the pressure in the regulator rapidly increases and 

the result is a dramatic temperature climb. The temperature may reach a level where the 

contaminants present can ignite.

Aluminum Construction The ten flash fires in this report all involved aluminum bodied regulators. The USFDA and 

some oxygen distributors recommend brass or nickel plated brass regulators for oxygen 

service because the metals are less of a flash fire hazard.

HAZARdS OF OXYgEn-EnRIcHEd AtMOSPHERES

By definition, an oxygen-enriched atmosphere exists whenever the oxygen concentration exceeds 

21 percent by volume or the partial pressure of oxygen exceeds 160 millimeters of mercury1

. While 

not all oxygen-enriched atmospheres represent an increased fire hazard, the administration of medical oxygen will usually produce an area of increased fire hazard. During the use of medical oxygen, 

the atmospheric pressure does not change; however, the oxygen displaces the air which contains 

mostly inert nitrogen, thereby raising the oxygen volume above 21 percent.

A less obvious means to raise the oxygen concentration above 21 percent by volume is to increase 

the pressure in the space beyond the atmospheric pressure of 14.7 psi. Examples of these spaces are 

hospital hyperbaric treatment chambers, diving and decompression chambers, and deep underground or pressurized tunneling work. As the space’s pressure increases above 14/7 psi, the oxygen 

concentration will rise even if the space is pressurized by using normal air. A several psi increase can 

qualify the higher-pressure atmosphere as oxygen-enriched.

The use of 100 percent oxygen during medical emergencies is a routine practice and all personnel should be familiar with the prohibitions of open flame and smoking when oxygen is in use. 

The volume (size) of the oxygen-enriched atmosphere will increase starting from the point of use. 

The amount of oxygen flowing, the size of the room or space, and the degree of confinement will 

determine the extent of the hazard. The interior of cars, ambulances, bathrooms, private offices, and 

bedrooms are examples of small volume area where the oxygen concentration could rise above 21 

percent. Emergency responders should always consider the space within three feet of the oxygen 

release point as being oxygen-enriched.

1Calculated by starting with atmospheric pressure at sea level of 760 millimeters of mercury (mm Hg) and multiply 

this number by the usual oxygen concentration by volume of 21 percent. Other forms of measurement of atmospheric 

pressure are 14.7 psi or 760 torr at sea level.
USFA-TR-107/March 1999 3

As the percentage of oxygen increases above 21 percent the fire hazard of most materials change 

making them easier to ignite and subsequent fires more intense. Materials which are difficult to burn 

or are even noncombustible in air can burn readily and intensely in 100 percent (or less) oxygen. 

Most types of clothing, the oxygen administration tubing and mask, valve seats, and even the metal 

pressure regulator and flow meter can burn. For example, a cutting torch uses oxygen under pressure 

to melt and burn through many metals and it is possible to shut off the fuel (typically acetylene gas) 

and keep the cut progressing using only oxygen. Fires involving high-pressure oxygen regulators and similar 

metal equipment are very rapid and violent events. The metal involved may melt and splatter around the 

vicinity of the incident to burn and ignite other combustibles.

Even minor contaminants such as skin and hair oils, hand lotions, hair care products, many lubricants, and some soap residues will burn readily in 100 percent oxygen. Surfaces and parts that come 

into contact with oxygen should be free of these contaminates at all times. Every effort should be 

made to keep the oxygen equipment clean when handling the oxygen cylinders, pressure and flow 

regulators, and filling connectors. Opening the oxygen cylinder valve raises the pressure inside of the 

equipment and develops heat that is commonly called “heat of compression”. The more rapid the 

pressure rise from quickly opening the cylinder valve, the more heat produced. Heat of compression 

has been sufficient to ignite contaminants or equipment components in the incidents described in 

this report.

Pure oxygen accelerates combustion resulting in higher flame temperatures than would be associated 

with fires burning in ambient air. Combustible material exposed to an oxygen-enriched atmosphere 

lowers the material’s ignition temperature. The resulting fires are very intense with rapid combustion 

and the release of large amounts of energy. If the fire is in a confined space, the rapid temperature rise 

and increase in pressure often results in the fire penetrating the walls of the enclosure quite quickly. 

The fire will involve all the combustible materials (flashover) in the room sooner than would be 

normally expected. Strong, relatively tight enclosures, such as a small room or an oxygen chamber, 

may experience nearly explosive like failure depending on the amount of combustible material (fuel 

loaded) and volume and percentage of pure oxygen available.

SPEcIAl HAZARdS

Where the demand for oxygen is large, liquid oxygen may be stored and used. Hospitals, laboratories, industry, demolition operations, and some home healthcare services use liquid oxygen. Most 

hazards associated with the use of liquid oxygen are independent of the storage volume. The storage 

volume can determine the size of the area which could be affected by the accidental release. The 

storage containers are heavily insulated pressure vessels (up to 300 psi) that have pressure relief 

valves for releasing excess pressure. During periods of low or no oxygen use, the container will likely 

discharge pure oxygen gas to reduce the pressure and temperature (auto-refrigerates). This action 

generates an oxygen-enriched atmosphere around an idle liquid oxygen container. Some home 

use containers have loose fitting covers which can spill liquid oxygen if tipped over. Contact with 

cryogenic liquids will cause skin burns. The liquid can also generate unusual failures to other objects 

because of the very cold temperatures.

Spillage or leakage of liquid oxygen will rapidly raise the oxygen concentration in the surrounding 

space. Liquid oxygen is approximately four times heavier than air and will spread along the floor 

or ground when spilled. Liquid oxygen will remain in liquid form for some time as it boils away 

into a gas and the oxygen-enriched atmosphere will build from the floor upwards. The fuel and the 

elimination of ignition sources near the spill should be the responders’ initial concern.
4 U.S. Fire Administration/Technical Report Series

A variety of fires occurring Nationally have identified several incidents where home oxygen therapy 

equipment contributed to fire intensity and spread. The oxygen cylinders emptied during the fires as 

should be expected from the heat exposure. The sudden supply of pure oxygen dramatically accelerated the fires and firefighters had to retreat form the area, bring additional hose streams to bear, and 

wait out the release. In one incident, the crew experienced a close call when a cylinder close to their 

position discharged near the end of the fire attack phase and the fire intensified unexpectedly.

IncIdEnt dEScRIPtIOnS

Between 1993 and 1999, ten flash fire incidents with medical oxygen cylinders and pressure regulators were reported by fire departments and emergency medical service agencies. The information 

which follows briefly describes each incident in order to provide the reader with an understanding 

of what occurred immediately before, during, and after. Detailed information about each incident 

was not always available. The descriptions, which follow, are included for risk reduction and educational purposes only and are not intended to suggest liability or responsibility.

Department of Fire & Life Safety 

Springfield, Oregon

On the morning of December 27, 1993, Medic Unit 839 from Station 3 was dispatched to a cardiac incident in a single-family dwelling. The three-member crew (captain, paramedic, and driver) 

treated the patient, had started her on oxygen, placed her on a stretcher, and were in the process of 

moving the stretcher out a sliding glass door. The “D” size steel oxygen cylinder was strapped in the 

horizontal position to a bracket at the foot of the elevated stretcher. The aluminum-bodied combination pressure and flow regulator was on the patient’s right side, as she lay face-up on the stretcher.

While the stretcher was passing through the sliding door, the regulator struck the metal doorframe. 

The driver at the stretcher’s foot reported hearing a hissing sound from the area of the regulator for 1 

to 2 seconds before a very bright fireball engulfed nearly the entire door opening. The fireball ignited 

the drivers station uniform, vest, and hair. He suffered first, second, and third degree burns to about 

40 percent of his body. His fingers, hands, and wrists were the most seriously injured body parts. He 

exited the porch area and rolled on the ground to extinguish the flames.

The paramedic at the heat of the stretcher dislodged the oxygen cylinder and regulator from the foot 

of the stretcher. It fell onto the concrete floor of the porch. The captain and paramedic moved the 

patient’s feet and pulled away the remaining burning and smoldering material from the stretcher. 

The patient did not receive additional injury from the flash fire. There was some delay in patient 

transport from the scene, however, the affect the delay had on her condition was not identified.

With the patient out of immediate danger from the fire, the captain went to the injured driver and 

found him to be conscious and breathing. The driver’s hair and some of his clothes were still smoking. The paramedic located and used a portable dry chemical fire extinguisher on the still smoldering 

materials from the stretcher and then on the clothing of the injured driver. The driver’s shirt and 

vest were removed and treatment of the burns began at this point. The captain requested an engine 

company, another medic unit, and a Deputy Chief be dispatched to the scene.

Damage to the residence consisted of several one to two square inch burns in the carpet near the 

door, a modest smoke stain on the side of the kitchen cabinets, and about a three feet in diameter 

soot and pattern of debris on the porch ceiling. The sliding door and a nearby porch wall also 

received smoke damage and debris spray.
USFA-TR-107/March 1999 5

The oxygen cylinder was attached to the regulator on December 24, 1993 and a new washer was 

placed between the cylinder valve and the regulator. The firefighter who made the change did not 

believe that more than one washer was present. The oxygen kit had been used and checked since the 

cylinder change, but the oxygen cylinder pressure was not checked during the December 27, 1993 

morning checkout. Instead of transfilling their own “D” size cylinders, the department obtained full 

cylinders from a local gas supplier. Samples of oxygen from three cylinders of the same lot number 

were tested and no evident of causal contamination was identified.

The involved aluminum-bodied regulator was an LSP Model 270-020. Most of the regulator’s interior 

was melted and the fire consumed many internal components. The high-pressure section was damaged 

more extensively than the low-pressure section. The fire jetted out of the regulator’s body between the 

two high-flow accessory outlets. These outlets were not being used at the time, only the liter flow valve 

was in operation. The regulator’s inlet filter screen was completely consumed in the fire. Independent 

laboratory analysis conducted that the flash fire started in the area of the filter screen.

Damage to the oxygen cylinder consisted of some heat damage to the threads on the valve stem. 

The damage indicated that the valve was about one-third of a turn from being fully open. The vale’s 

position was not believed to be relevant to the incident’s cause. The flash fire did not affect the steel 

cylinder body.

The firefighter’s eyeglasses and station uniform are believed to have reduced the amount and severity 

of his injuries. His uniform pants and long sleeve shirt were both flame/fire retardant. His wrists 

were injured because the shirtsleeves were partially rolled up. The sleeveless vest was the insulated 

nylon type and their use was discontinued after the incident. 

The cause of flash fire was determined to be from the impact of the regulator with the doorframe. 

Two possible ignition scenarios were identified. The impact may have released hydrocarbon-based 

contamination inside the regulator that ignited on impact with the inlet filter screen. Another potential ignition scenario was the frictional heating of a hydrocarbon-based contaminant caught between 

the regulator and the cylinder valve stem or caught in the washer between the valve and the regulator. The extension of fire to the aluminum-bodied regulator followed the first material ignited.

Union Colony Fire/Rescue Authority 

Greeley, Colorado

On July 13, 1995, three members of Engine 3 were beginning to treat a patient complaining of 

chest pains. While the lieutenant and one firefighter were assessing the patient and taking vital sign 

measurements, the engineer was preparing a “D” size aluminum oxygen cylinder equipped with 

an aluminum-bodied combination pressure and flow regulator contained in a nylon sling bag. The 

oxygen mask had been handed off from the engineer for placement on the patient. The mask’s tubing end was attached to the regulator’s outlet. The engineer was opening the oxygen cylinder’s valve 

with his left hand when the regulator erupted in flames. Witnesses reported hearing a sound similar 

to a small explosion or pressure rupture simultaneously with the flames. The sound of pressurized 

gas escaping accompanied the flames.

The engineer managed to close the cylinder valve before he dropped the nylon bag with the cylinder 

on the floor. He immediately exited the single-family residence’s by the front door. The patient was 

being treated in the home’s front entrance foyer. The lieutenant kicked the still burning bag and 

oxygen cylinder out the front door while the patient and firefighter proceeded a short distance up 

the stairs toward the second floor. The lieutenant followed the engineer and oxygen cylinder out the 
6 U.S. Fire Administration/Technical Report Series

front door where he requested additional resources and began treatment of the engineer’s injuries. 

His injuries consisted of third degree burns on the left hand and second degree burns to the left arm, 

right hand, and abdomen. The engineer was wearing rubber gloves at the time of ignition and the 

left glove was melted on his hand. Immediate treatment consisted of cooling the burns with sterile 

water. The paramedic ambulance crew which arrived during the water application phase provided 

further treatment. The seriously injured engineer was transported to the hospital and admitted.

The original patient did not receive additional injuries from the oxygen cylinder and regulator fire. 

The heat and molten metal being scattered by the flames damaged the home’s entrance area. In 

addition, smoke had to be removed from the inside of the house. Burn damage consisted of several 

charred spots on the floor, heat and flame marks on the walls, and heavy smoke stains on the outside 

screen door. Metal fragments and pieces of burned rubber glove were scattered on the floor near the 

entrance. The metal fragments were later collected for evidence as part of the scene investigation.

The firefighter who was providing most of the treatment to the original patient at the time of the 

incident reported removing a blanket which was hanging above the entrance area. A small portion of 

the blanket had ignited so the firefighter removed it from the entrance and brought it to the kitchen. 

In the kitchen the firefighter soaked the blanket with water at the sink to extinguish the flames. When 

a second ambulance arrived, the original cardiac patient was transported to the hospital.

Engine 2, one of the additional resources requested, arrived at the scene while the sling bag containing the oxygen cylinder was still burning. The crew extinguished the residual fire in the bag, 

assisted with the smoke removal from the house, and helped finish the assessment and transport of 

the original patient.

Engine 2’s lieutenant reported these observations about the portable oxygen unit. “The cylinder’s 

valve was turned off; the liter flow valve on the regulator was set at zero (0); and the pressure gauge 

on the regulator indicated 1,100 psi.” Engine 2’s lieutenant then proceeded to empty the oxygen 

cylinder by opening the valve. After the oxygen cylinder was emptied, the regulator was removed 

and both items retained by the department. The oxygen cylinder had a hydrostatic pressure test date 

of April, 1990. Date of manufacture for the regulator could not be determined.

Initially, local investigators externally examined the oxygen cylinder, cylinder valve, and regulator. 

Two consultants with oxygen system experience performed an extensive examination using various 

methods including electron microscopy. Visually the aluminum oxygen cylinder had fire debris and 

soot on the exterior but it did not receive significant fire damage. The cylinder valve also had soot 

and fire debris on the surface. In addition, the valve experienced external heating in the area of the 

indexing pins and gasket seal for the regulator’s attachment. There was no evidence of internal combustion in the cylinder valve.

The aluminum-bodied oxygen regulator received the most fire damage both externally and internally. There was ignition and sustained combustion of the aluminum body and much of the internal 

mechanisms. Externally, there was a large opening in the side of the regulator. Internal examination 

indicated that the fire developed upstream (toward the oxygen cylinder) of the regulator’s main 

valve seat and progressed downstream with the flow of oxygen. The violence and force of the oxygen 

fed metal combustion expelled molten metal and flames from the regulator.

More damage would likely have resulted to the regulator and probably the house if it were not for 

the engineer closing the cylinder valve before letting loose of the sling pack. His actions stopped 

the aluminum fire and probably prevented further damage to the cylinder valve and the surround-
USFA-TR-107/March 1999 7

ing area. The closing of the cylinder valve agrees with the post-incident observations of Engine 2’s 

lieutenant and was likely an instinctive rather than a deliberate reaction.

Although the oxygen contained in the involved cylinder was lost, the department was refilling the 

“D” size cylinders from a two bottle “H” size oxygen cascade located at their Station 1. A sample 

from this cascade was analyzed and the test results indicated that the oxygen met all Compressed Gas 

Association medical oxygen standards.

The damaged regulator and the oxygen cylinder valve were chemically analyzed for residual hydrocarbon contamination. In addition, ten bourdon tubes from new oxygen regulator pressure gauges 

were chemically analyzed. A trace (0.02 to 0.06 milligrams) amount of total hydrocarbon was 

detected in the damaged regulator parts. The sample bourdon tubes contained significantly more 

total hydrocarbons ranging from 2.3 to 20 milligrams per tube.

Based on the testing, it was concluded that the most likely cause of the incident was hydrocarbon 

contamination with the source being the regulator pressure gauge’s bourdon tube. The heat of compression from the high-pressure oxygen filling the regulator was the likely ignition source. Analysis 

of the internal damage to the regulator also supports the conclusion.

As a result of this incident, the Union Colony Fire/Rescue Authority has made the following procedural and equipment changes:

•	 Ceased transfilling "D" sized oxygen cylinders. They currently purchase (exchange) filled

cylinders from a gas supplier.

•	 Removed all aluminum-bodied regulators from service and replaced them with brass/nickel

plated regulators.

•	 Introduced operating procedures for closing the cylinder valve and turning the regulator's

liter flow valve to zero (0) flow when not in use.

•	 Reviewed and reinforced the Emergency MedicalTechnician – Basic (EMT-B) training on the

installation and operation of oxygen regulators.

•	 All maintenance and annual testing of oxygen regulators is performed by a commercial

regulator maintenance facility.

Austin Fire Department 

Austin Emergency Medical Services 

Austin, Texas

A police officer complained of hearing loss and a firefighter received burn injuries to hands and 

face when a flash fire involving an oxygen cylinder occurred about 1:00 p.m. on June 14, 1996. The 

incident involved a “D” size aluminum oxygen cylinder and an aluminum-bodied regulator which 

was being used during a cardiac arrest incident inside a house.

The incident occurred as firefighters started to administer oxygen to a cardiac arrest patient from 

a cylinder that was standing upright in their airway supply bag. As the oxygen cylinder’s valve was 

opened, a very loud pop (almost like a discharge from a firearm) was heard and the unit caught 

fire. The operator’s reflex was to shut off the cylinder valve and another emergency responder threw 

the bag out the front of the house. The flash fire resulted in a few spot fires in the house from the 

regulator’s molten metal being scattered about.
8 U.S. Fire Administration/Technical Report Series

The Austin Fire Department and Emergency Medical Services were not refilling the “D” size cylinders 

from a larger cascade system at the time. A commercial gas supplier provided cylinder refills, inspection, and maintenance. The oxygen cylinder had been changed about 5:00 a.m. on the day of the 

incident and was operated at least twice before the fire occurred. One operation was during the daily 

vehicle checkout and the second was during another emergency medical call.

Because of pending litigation, details on the ignition sequence and the amount of damage to the oxygen cylinder and the regulator were not available. As a result of this incident, the Austin Emergency 

Medical Services and Austin Fire Department have removed all aluminum-bodied regulators from 

use and changed to brass regulators.

Houston Fire Department 

Houston, Texas

On Saturday, June 15, 1996, Engine 6 and Medic 1 were dispatched to a trouble breathing call at 

about 12:43 p.m. The engine company consisting of an officer, engineer/operator (E/O), and two 

firefighters arrived at the scene before the ambulance. The company was the first responder to the 

medical emergency. They carried the engine’s medical kit and portable oxygen caddy to the patient’s 

second floor apartment. The oxygen caddy is a canvas covered wire frame assembly containing a 

“D” size aluminum oxygen cylinder with an aluminum-bodied regulator. While the officer gathered 

medical history information, one firefighter measured vital signs and the patient was started on 

oxygen through a mask at six liters per minute (LPM). Medic 1’s two-member crew arrived during this process with their cardiac monitoring equipment, drug box, and another portable oxygen 

caddy. During the paramedic’s patient assessment, they oxygen mask was removed and laid on the 

carpeted floor. The incident investigation suggests that the oxygen continued to flow from the mask 

at six lpm.

A decision as made that Medic 1 would transport the patient. One of Engine 6’s firefighters was sent 

to bring Medic 1’s stretcher and the E/O began to gather the engine’s medical kit and transfer the 

patient to the medic unit’s portable oxygen caddy. The E/O opened Medic 1’s oxygen caddy and 

observed that the pressure gauge on the aluminum-bodied regulator indicated zero pressure. He 

opened the valve on the aluminum cylinder. Immediately a bright flash and a very loud pop occurred 

and personnel reported a hissing sound afterwards.

The flash fire contacted the E/O and his clothing ignited. The fire quickly engulfed both portable 

oxygen caddies, the carpeting, and spread to the furniture in the patient’s living room. The engine 

company officer immediately began to clear the room but the fire’s position blocked some occupants 

from reaching the apartment’s door. The burned E/O, an Engine 6 firefighter, and a member of Medic 

1’s crew escaped out the door. The patient, company officer, and paramedic escaped through a nearby 

patio door onto the balcony. An urgent radio request from Medic 1 for a structure fire box assignment was made about 1:00 p.m.

The E/O was burned on his hands, arms, stomach, face and one leg. The extent of injury included 

third degree burns on both hands and arms; he also had first, second, and some third degree burns 

on the other body areas. The E/O described the flash as “blinding” in that he could not see anything 

afterwards. He did not remember exactly how he escaped the apartment or how the flames on his 

body and clothing were extinguished. Finding himself at the bottom of the stairs in the apartment 

building’s courtyard, the E/O proceeded toward the engine on his own. There he found the unit in 

pump and a hoseline off and he was quickly assisted into Medic 1. His on-scene treatment consisted 

of pouring saline water on the burns and rapid transport to an emergency burn center.
USFA-TR-107/March 1999 9

The hoseline and the engine being placed into pump was the work of the firefighter who had 

been sent for Medic 1’s stretcher. The hoseline was advanced to the company officer on the balcony 

who directed it on the fire. A ladder from the engine was also placed to remove those trapped on 

the balcony. An engine company member confirmed with dispatcher Medic 1’s urgent box alarm 

request. The original patient and paramedic were evacuated from the balcony. Another ambulance 

was brought to the scene for the original patient as Medic 1 transported the seriously injured E/O.

The fire destroyed most of the living room and caused significant damage to the dining room and 

kitchen. The Houston Arson Bureau investigated and documented the fire scene. The Bureau collected 

the two damaged oxygen units, Medic 1’s equipment, the E/O’s shirt and pants, and a section of 

carpet that had the oxygen tubing and facemask melted into it. The E/O’s clothing and the carpet 

section were to be submitted for analysis of hydrocarbon contamination because of the rapid fire 

development. No results of this analysis were mentioned in the Bureau’s reports and it is not certain 

that the testing was completed. The oxygen saturation of the carpet by the flowing oxygen mask 

could explain the rapid burning of the material.

The damage to one of the oxygen regulators was described as a hole about the size of a quarter in 

the side near the overpressure vent holes. The interior damage will be discussed below. The Bureau’s 

cause and origin investigation concluded that the fire was caused by a malfunction in the oxygen 

bottle but the ignition source was not determined. 

A safety investigation into the cause of the incident began immediately and involved the department’s 

safety administrator, the Assistant Fire Chief of Safety and Staffing, and the on-duty District Chief of 

Safety and Staffing learned of the Austin, Texas medical oxygen incident of the previous day by coincidence while he attended another fire. He contacted the Austin Fire Department that night to obtain 

further information about their incident. One concern about possible oxygen gas contamination as a 

cause of the two incidents was concluded to be unlikely as two different compressed gas companies 

supplied the two departments. However, it was discovered that both departments used the same type 

aluminum-bodied regulators and the damage on each regulator was similar. The cause of the flash 

fire was unclear although the possibility of contamination and heat of compression as the ignition 

source were discussed.

On Tuesday morning, July 16, 1996, the Houston Fire Department experienced another flash fire 

involving Medic 31’s portable oxygen caddy. The unit included a “D” size aluminum cylinder with an 

aluminum-bodied regulator. The ambulance was under-going an annual inspection by the Houston 

Health and Human Service Department.

The inspector removed the portable oxygen caddy from the ambulance and laid it on the ground. 

Opening the cover to expose the regulator, he opened the cylinder valve with his left hand while 

he held the bottle with his right hand. He heard a noise that he thought was the regulator leaking 

but observed that the pressure gauge moved and the flow meter was in the off position. As these 

observations were being made, he felt a burning sensation and observed flames around his right 

hand. He immediately shut off the oxygen cylinder’s valve. As he completed shutting off the cylinder, 

an extremely loud pop/explosion came from the unit. After the noise he observed that the pressure 

gauge was now at zero and the fire had stopped. The inspector estimated that all of this activity 

occurred in a period of about three seconds. The inspector was wearing blue colored plastic gloves 

at the time. He received a first degree burn on a finger in his right hand and was given first aid treatment at the scene.
10 U.S. Fire Administration/Technical Report Series

Another witness described the fire as a light around the oxygen regulator similar to a flashlight in 

the area. He also indicated that the explosion sounded like a shot from a .30-06 rifle. After the fire 

was out, the portable oxygen caddy was carried about 30 feet from the ambulance where it remained 

until the investigation began.

The Assistant Chief of Safety and Staffing was notified of the incident and he proceeded to the scene 

to direct the investigation. Written statements of those involved were made and the oxygen unit 

secured. The damage to the aluminum-bodied regulator in the second incident was not as severe as 

the first. Externally, a plastic plug in one of demand valve attachment ports was partially melted and 

some soot was observed on the regulator body.

The oxygen cylinders and combination pressure and flow regulators from both incidents were submitted to an independent testing laboratory on July 16, 1996. The Houston Fire Department issued 

a bulletin dated July 16, 1996 immediately discontinuing the use of all portable “D” size oxygen 

cylinders until further notice. Ambulance on-board oxygen systems were to remain in-service and 

could be used for patient treatment. All “D” size oxygen cylinder regulators were collected within 

each district and new regulators were purchased. Portable oxygen administration resumed after the 

new pressure regulators were received and placed in service.

Both aluminum-bodied pressure regulators were identified as LSP Model 270-020. The regulator 

from the first incident was removed from the aluminum oxygen cylinder, which had also been damaged in the fire. Department records indicate that the regulator was placed in service on November 

29, 1994. Besides the quarter size hole burned through the body, the identification tag was illegible, 

and the rubber in metal ring gasket between the regulator and cylinder valve body was burned. The 

X-rays of the regulator indicated that most of the internal components were either consumed or 

damaged. The regulator was not disassembled further.

The pressure regulator from the second incident was also examined externally and X-rays taken. 

The plastic plug on one of the demand valve parts was damaged and the X-rays suggested that the 

internal parts were essentially intact. The regulator was carefully taken apart and the internal components and contamination were collected. A number of analytical tests were conducted to identify the 

contamination and the condition of the parts.

The regulator’s stainless steel inlet screen was covered with visible particles consisting of copper 

colored metallic chips, white powder, and green plastic flakes. Inlet screens from 10 to 12 other 

LSP model regulators from the Houston Fire Department were also collected and examined. Various 

amounts of similar debris were found on all the screens. Through analytical testing, the copper 

colored metallic chips were determined to be brass. The source was believed to be grindings from 

the oxygen cylinder valve. The white powder was identified as aluminum oxide and the source was 

thought to be corrosion product from the regulator body. The green plastic flakes were Teflon, which 

was used as a coating on the oxygen cylinder valve threads.

Besides the visible (to the unaided human eye) particles, the screens contained invisible traces of 

chemicals associated with nylon. The source of this debris was believed to be the oxygen cylinder 

valve seal. The laboratory indicated another, but less likely source, as a combustion product of the 

damaged plastic plug in the demand valve port.

The laboratory concluded that the two flash fires were caused by the ignition of non-metallic contamination in the regulator either by heat of compression or by metallic particle impact. Another 

ignition scenario involved the Teflon seal on the control piston between the high and low pressure 
USFA-TR-107/March 1999 11

sections. Metallic contamination embedded in the seal could have been ignited by impact on the seat 

and the subsequent ignition of the seal and regulator parts.

The Houston Fire Department contracted the same testing laboratory to examine two of the replacement oxygen regulators after about ten months of service. The regulators were constructed of anodized aluminum, which improved the ignition resistance. The units had an inlet filter constructed of 

sintered bronze rather than stainless steel. 

The analysis indicated that, based on literature, the anodized aluminum would be more ignition 

resistant than non-anodized aluminum. But the material is till not as ignition resistant as brass. The 

analysis discovered that the sintered bronze filters were not performing in accordance with manufacturer specifications because the holes were larger than acceptable tolerance and did not prevent 

contaminates from entering the regulator.

The interior of both oxygen regulators contained visible (under magnifications of 1:1 to 30:1) particle contamination. The particles were identified as brass and Teflon consistent with that in the flash 

fire investigation and produced by the oxygen cylinder valve. Also, particles of anodized aluminum 

from the regulator were found in both the high and low pressure sections.

After the examination, the regulator manufacturer replaced the out of specification sintered bronze 

filters. The specified filters would prevent the larger particles form entering inside the regulator. 

However, the sintered bronze filter would accumulate this material and cleaning would be required. 

Also, small particles could pass through the filter and potentially collect inside the regulator. The 

laboratory report also suggested modifications to the oxygen cylinder valve to reduce the generation 

of brass and Teflon particles.

Gurnee Fire Department 

Gurnee, Illinois

On March 23, 1997 a firefighter was in the process of performing the usual daily equipment checks 

at about 8:00 a.m. on one of the department’s modular paramedic ambulances. The unit involved 

was a 1993 Extra Heavy Duty Golden Eagle by Excellence, Inc. on a 4700 LP Navistar chassis. The 

firefighter had taken the portable Nylon bag containing an “E” size aluminum oxygen cylinder and 

aluminum pressure regulator from its storage location. The bag was placed on the gurney near the 

head end. Partially removing the bottle and regulator from the bag, the firefighter opened the oxygen 

cylinder’s valve. He noticed that the regulators pressure gauge did not move as expected when the 

cylinder was opened.

As he lifted the pressure regulator to investigate, he later reported seeing a bright flash followed by 

intense pain and the inside of the ambulance was ignited. Other firefighters in the station responded 

to the fire in the bay and an alarm was sounded for a structure fire in the station. While some personnel attended to the injured firefighter, others were attempting to reach turnout gear and move 

adjacent apparatus from the station and to get a hoseline on the fire. By the time the fire was extinguished, the ambulance module and chassis were a total loss along with most of the equipment on 

the unit. One nearby apparatus suffered heat damage to the finish and plastic components. Smoke 

damage included the entire apparatus area and most of the living quarters. One other firefighter was 

transported to the hospital for smoke inhalation.

The firefighter involved with the ignition was seriously injured. At the bright flash, he instinctively 

raised his left arm and hand to shield his face. It received third degree burns from the hand to the 
12 U.S. Fire Administration/Technical Report Series

biceps. In addition, he received second degree burns to his face, neck, right hand, chest, and front 

of his legs. Some metal particles, believed to be inhaled during the incident were discovered in his 

lungs during x-rays. It was noted that the eyeglasses that he wore probably prevented injury to his 

eyes.

The oxygen cylinder, aluminum combination pressure and flow regulator, and nylon bag were less 

than five years old and were purchased with the ambulance. There were no prior reports of the cylinder or the regulator leaking or performing erratically before the incident. The date and time the 

portable oxygen bag and equipment was last used was unknown. The injured firefighter was beginning the shift and this was his first contact of the day with the equipment.

The post incident investigation revealed that the fire began in the oxygen cylinder’s control (post) 

valve in the vicinity of the valve seat. The fire spread to involve the non-metallic gasket between the 

regulator and the cylinder valve body. The fire also spread to damage the regulator, consuming the 

aluminum piston, and burning through the body near the high flow check valve. The conclusion 

on the point of origin was based upon disassembly of the equipment remains to expose the burn 

patterns. The nonmetallic cylinder valve seal was damaged where the seal meets the metal valve seat. 

It is believed that the damage observed in this area was the result of wear or a combination of wear 

and contamination.

During the investigation, the metal screen in the combination pressure and flow regulator was examined. Under the electron microscope, the debris on the screen was identified as Teflon, copper, brass, 

and polyphenylene oxide from the nonmetallic valve seal. The screen was located between the oxygen cylinder and the regulator’s pressure gauge. The debris captured by the screen may explain why 

the pressure gauge did not give a reading when the cylinder’s valve was opened.

The Gurnee Fire Department has instituted procedures for the use of oxygen units that includes the 

following. Before opening the cylinder valve, the flow regulator should be set to zero (0). The cylinder valve should be opened slowly to reduce the heating caused by the oxygen’s compression in the 

regulator’s passages. The procedure is to be followed during equipment checks out and at emergency 

incidents. The department also intends to replace the aluminum-constructed regulators with ones 

constructed of brass, to reduce (but not entirely eliminate) the potential for similar ignitions.

Broward County Fire/Rescue 

Broward County, Florida

A firefighter at Station 17 was performing the daily vehicle checkout on June 12, 1998. The engine 

was used for basic life support emergencies and carried a jump bag style oxygen cylinder and regulator in a side compartment. The firefighter opened the bag, raised the cylinder to a vertical position, 

opened the cylinder valve, and the unit burst into flames. His injuries consisted of first, second, and 

third degree burns from the waist up on about 36 percent of his body.

The engine was parked on the ramp outside the station and two firefighters were in the process 

of washing the opposite side. These company members and on-duty medical personnel afforded 

a quick response to the flash fire. As one firefighter responded to the burning firefighter, the other 

directed the hose, which was being used to wash the apparatus, first on the burning firefighter and 

then into the compartment and the burning oxygen bag. Although the fire was confined to the one 

compartment, it was heavily damaged and all of the contents destroyed.
USFA-TR-107/March 1999 13

The Florida State Fire Marshal’s Office assisted in the investigation and submitted the damaged oxygen cylinder and regulator to an independent testing laboratory for analysis. The expert’s preliminary 

report suggested that the ignition sequence involved metal particles which were ignited by the heat 

of compression from the oxygen filling the regulator. The investigation was continuing at the time 

of this report. On February 5, 1999, NIOSH issued Firefighter Fatality Investigation Report 98F-23 

on the incident. (See Appendix A)

Greenville County Emergency Medical Service 

Greenville, South Carolina

The fire incident involved a two year old Type I ambulance that was on a Ford chassis. The ambulance 

attendant was completing a vehicle checkout at about 6:00 p.m. on August 27, 1998 as part of a shift 

change. The unit was parked outside the station and the attendant was standing outside the ambulance at the passenger side door to the module. The oxygen cylinder and regulator were contained in 

a padded nylon bag, which was resting on the floor of the entrance. When the oxygen cylinder valve 

was opened, the bag bust into flames.

The attendant received second and third degree burns over 15 percent to 20 percent of her body. The 

areas affected included her hands, arms, abdomen, and thighs. No respiratory burns were received as 

a result of the incident. She was transported to a regional burn center for treatment. 

At the time of the incident, the attendant was in a station uniform consisting of a polyester and cotton blend, blue on blue shirt and blue polyester pants. The pants did melt during the fire and attached 

to her thighs. Investigators believe that the attendant’s injuries would have been more serious if she 

had been inside the ambulance module at the time of ignition.

Within the first two minutes after ignition, the entire ambulance interior was fully involved. The onboard oxygen system did not contribute to the extent and rapid fire spread. It was intact following 

the fire and was turned off at the oxygen cylinder. The ambulance, chassis, and contents have been 

declared a total loss.

The oxygen bag contained an “E” size aluminum cylinder and aluminum-bodied regulator. The age 

of the cylinder and regulator has not yet been determined. The oxygen cylinder was nearly full at 

1,800 psi and was last used on the morning of the incident. No problems were reported with the 

unit’s operation at that time. Greenville County EMS used an exchange program with a gas supplier 

for their portable cylinders. The regulator model was included in the May 1997 recall notice (See 

Appendix C). However, Greenville had not received the notice before the incident and the filter 

retrofit kit had not been installed. After the incident, Greenville contacted about 33 surrounding fire 

departments and emergency medical service providers and found that none had received the recall 

notice.

About 75 percent of the regulator was destroyed in the fire. The aluminum oxygen cylinder was very 

severely damaged. After the fire, the cylinder had about a four inch long vertical opening (slit) starting in the top dome and extending down into the vertical body. The ambulance attendant reported 

that a very large, bright fireball was emitted from the nylon bag as the cylinder valve was opened. The 

presence of a protective guard on the regulator pressure gauge may have contributed to the extent 

of the damages. The guard interfered with the regulator’s vent holes that operate to relieve internal 

pressure. The interference resulted in the pressure developed by the internal fire being unable to 

vent properly. The cause of the flash fire is still under investigation. The remains of the regulator and 

cylinder were sent to an independent expert who is familiar with oxygen systems.
14 U.S. Fire Administration/Technical Report Series

As a result of the incident, Greenville County EMS inspected all of the oxygen regulators on its 18-

ambulance fleet. The regulators were specifically checked for the retrofit kit recommended by the 

manufacturer. They also investigated alternate regulators that are constructed of materials other an 

aluminum, and reviewed the Compressed Gas Association Bulletins concerning oxygen systems.

Oak Creek Fire Department 

Oak Creek, Wisconsin

About 7:2 a.m. in the morning on January 29,1999, firefighters were performing daily equipment 

checks in accordance with department standard operating guidelines (SOGs). A nylon constructed 

airway equipment bag was removed from the third due ambulance at this station and placed on the 

floor. The bag contained a “D” size aluminum oxygen cylinder with an aluminum-bodied combination pressure and flow regulator. The firefighter first checked to make sure the flow meter valve and 

the main line gauge were on zero; he then opened the valve and the unit burst into flame. The exact 

ignition cause is still under investigation.

The firefighter received first and second degree burns to the face, neck, and inner thighs and second 

and third degree burns to the hands and arms. The firefighter’s station uniform helped reduce the 

amount of burn injury on the covered parts of his body. The station uniform consisted of a 100 

percent cotton tee shirt and fire retardant trousers. The department requires responding members to 

wear Nomex coveralls/jump suit over street clothes when not in uniform. The fire retardant trousers 

were heavily damaged by the incident.

The department estimated that he oxygen regulator involved was purchased between 1989 and 1990 

and the ambulance was also obtained in 1990. However, equipment was routinely traded among the 

department’s three ambulances at this station making equipment purchase date to unit date inaccurate. The records available suggest that the airway bag and regulator was last used with a patient 

in October 1998, some three months prior. The oxygen cylinder involved may not have changed 

since the last use with a patient and would have been checked daily according to department SOGs. 

However, the aluminum cylinder may have been changed or filled because the SOGs also indicate 

that a cylinder should be changed or filled when below 1700 psi. The department transfilled the “D” 

sized aluminum cylinders from an in-house cascade system.

The fire spread to the nylon airway equipment bag and its contents. Firefighters extinguished the fire 

with a carbon dioxide extinguisher and noted that the fire’s intensity was decreasing at the time. This 

observation suggests that most of the oxygen in the cylinder had discharged. Damage to the station 

and equipment consisted of a scorched concrete floor, and minor paint damage and soot coating to 

the ambulance and a nearby equipment trailer. The removal of the bag from inside the ambulance 

contributed to the minimal station and equipment damage.

The aluminum-bodied regulator was a model (LSP) L270-020 and subject to the May 20, 1997 

recall notice. Unfortunately, the department was not aware of the recall and the regulator was not 

retrofitted with the sintered bronze inlet filter. The department noted that the oxygen regulators 

were not subject to an annual maintenance or cleaning program. Such a program was not included 

in the manufacturer’s instructions. Any oxygen regulator that failed the daily checkout was removed 

for repair.

Since this incident, the department has replaced the all aluminum pressure regulators with units 

having an aluminum body with brass inserts. The brass inserts improve the regulator’s resistance to 

internal ignition. The department is also purchasing new aluminum oxygen cylinders with pressure 
USFA-TR-107/March 1999 15

gauges. The gauge will eliminate the need to open the cylinder and charge the regulator to check 

the cylinder’s pressure. The department has ordered additional cylinders to eliminate the need for 

transfilling from their oxygen cascade. An outside gas supplier will provide oxygen in the final use 

cylinder for the department.

Truckee Meadows Fire Protection District 

Reno, Nevada

On Monday morning, January 25, 1999, Engine 7 had returned from a structure fire and the unit 

was parked outside the station for the crew to clean and check equipment. The intermediate level 2 

EMT firefighter on the company went to the rear of the engine to perform the daily check on the 

EMS equipment bag. The orange, 24 inch by 18 inch by 8 inch, nylon bag was kept in the upper rear 

compartment over the tailboard area. Inside the bag was a jumbo “D” sized aluminum oxygen cylinder and aluminum-bodied combination pressure and flow regulator. The bag also contained drugs, 

IV bags and tubing, airways, oxygen masks and tubing, bandages, blood pressure kit, etc.

The firefighter partially removed the EMS bag from the chest high compartment such that the bag 

was about one-half in and one-half out. The bag was opened enough to reach the oxygen cylinder 

and regulator which were lying on their side. Orienting the cylinder to observe the regulator’s 

pressure gauge, the valve was opened and the sound of high pressure oxygen escaping was heard. 

The oxygen unit burst into flames and the firefighter yanked his hands out of the EMS bag. As the 

firefighter hurried to cool himself with water, the bag fell out of the compartment to the ground. The 

fall caused the neck of the cylinder to break separating the valve and regulator from the body. The 

separation resulted in some rocketing/spinning of the burning bag from the rapid depressurization 

of the oxygen cylinder.

2 Intermediate Level – Below paramedic certification but the level does include the administration of

a limited number of drugs, intubation, starting of IV’s, and cardiac defibrilization.

The firefighter’s injuries consisted of second degree burns to both hands up to his wrist, some first 

degree burn on the side of his face, a small area of second degree burn behind his ear, and some 

burned hair on his head. His station uniform and the procedure utilized for opening the oxygen 

cylinder were both credited with limiting the burns and injuries. The firefighter was trained to turn 

his face away from the cylinder and close his eyes when opening the valve. The Nomex uniform 

trousers, heavy cotton uniform jacket, and cotton tee shirt performed very well. Melted parts of the 

EMS bag were found on the firefighter’s hands and uniform jacket after the incident.

The engine was moved forward and the burning bag was extinguished with water from a nearby 

garden hose. The engine damage consisted of some melted lights and adjacent equipment and some 

soot marks and scorching on the paint. About one-half of the EMS bag was consumed in the fire. Part 

of the aluminum regulator was destroyed leaving melted aluminum on the oxygen cylinder. Most of 

the regulator remains and it will be analyzed in an attempt to identify the ignition sequence.

The department was unable to identify the age of the oxygen pressure regulator. It was one of about 

50 the department owns. The regulator involved was an (LSP) L270-020 model and was equipped 

with the sintered bronze inlet filter. The department retrofitted the filter themselves as part of the 

Allied Healthcare Product recalls on May 20, 1997. Other regulator maintenance consisted of keeping the units clean and the daily equipment check. Manufacture instructions did not describe specific 

annual maintenance, testing, and cleaning procedures.
16 U.S. Fire Administration/Technical Report Series

The oxygen cylinder was replaced the evening before and, other than opening it to check the seal 

between the cylinder and regulator at the change out time, it had not been used. The department 

was not transfilling oxygen cylinders and exchanged empty for full cylinders with a supplier. Each 

full cylinder had a paper sticker that indicated the oxygen lot number and would identify when the 

cylinder was filled. The sticker was destroyed in the flash fire. 

As a result of the incident, the department has replaced all of its oxygen regulators with units constructed of chrome plated brass. They are also investigating a more durable means of tracking oxygen 

lot information than the paper stickers.

Additional Incidents

The FDA has reports of additional flash fire incidents with oxygen regulators. In addition, there has 

been at least one incident with a contaminated brass-bodied oxygen pressure regulator on a large, 

“H” sizes, steel cylinder. The regulator was attached to a cylinder for use on a wheeled cart in a health 

care facility and where it was used for patient oxygen therapy. The pressure regulator’s T-handled 

adjusting screw had become difficult to move. A maintenance employee used a popular hydrocarbon 

based lubricant spray on the screw’s threads. The lubrication was done without the knowledge of 

the nursing or respiratory therapy staff who would have likely recognized the danger in applying a 

hydrocarbon lubricant.

The next time the valve on the oxygen cylinder was opened, the heat of compression ignited the 

residual hydrocarbon contamination inside the regulator. The burning of the residual contamination 

was sufficient to start the internal parts of the pressure regulator and the brass body on fire. The 

health care worker who opened the oxygen cylinder was injured by the molten metal and blowtorch 

like flames. Once the cylinder valve was closed stopping the oxygen flow, the fire ceased.

OXYgEn REgUlAtOR REcAll And SAFEtY nOtIcE

On May 20, 1997 Allied Healthcare Products, Inc. issued a recall/safety notice that affected two models of aluminum-bodied regulators. The models involved were Life Support Products (LSP) Models 

L270-020 and L270-050. The notice also advised to inspect all oxygen regulators for visible contamination and general condition. Any dirty or damaged regulator should be removed from service 

for special cleaning or repair.

The Allied notice indicated that Model Nos. L270-020 and L270-050 may have been involved in 

six fire incidents over the previous three years. Their investigation reports indicate that hydrocarbon 

contamination has been the most likely cause of the oxygen regulator fire incidents. The contamination, according to the notice, was introduced into the regulator during maintenance or use.

To improve their oxygen regulators’ resistance to the contamination, Allied Healthcare is providing a 

sintered bronze inlet filter to replace the current filter in existing regulators. The recall notice indicates 

that the new filter will be helpful in preventing contamination which may result in a fire. The notice also 

cautioned that all possible flash fire scenarios would not be eliminated. Allied Healthcare’s customer service can be 

reached at (800) 216-4624 or by FAX at (888) 231-5273. (See Appendix C for copy of the notice.)

The recall/safety notice and the attached information sheet stress the importance of keeping oxygen 

equipment clean and avoiding contamination of all kinds. In pure oxygen almost anything (dust, 

dirt, metal particles, oils, lubricants, etc.) can act as a fuel. Hydrocarbon based materials are especially susceptible to ignition and fire.
USFA-TR-107/March 1999 17

On February 4, 1999, Allied published a wider recall notice in USA Today. The recall included all Life 

Support Products (LSP) oxygen regulators. The recall’s stated purpose is to replace aluminum components in the high-pressure sections with brass components. The model numbers listed in the recall 

are LSP 106, LSP 270, LSP 280, LSP 370, and LSP 375.

The recall notice also stressed the need to immediately remove from service all LSP regulators that 

did not have the sintered bronze filter installed. Also to be removed from service were all regulators 

made by Robertshaw Controls Company, Inc., LSP’s predecessor corporation.

Allied also announced that they will stop the manufacture of aluminum-bodied regulators. They will 

offer a trade-in program for the aluminum regulators on its new brass regulators in the future. The 

contact information for the Recall Coordinator is:

Telephone: 800-216-4624 (Monday to Friday 8:00 a.m. to 5:00 p.m. CST)

Fax: 888-231-5273

Mail: LSP Regulator Recall Coordinator

Allied Healthcare Products

1720 Sublette Blvd.

St. Louis, MO 63110

The United States Food and Drug Administration (USFDA) is the government rule making authority 

for medical devices including oxygen regulators. The USFDA issued a Public Health Advisory dated 

February 4, 1999 titled “Explosions and Fire in Aluminum Oxygen Regulators” (See Appendix A). 

The Advisory briefly describes the problem, offers two recommendations, and provides information 

about reporting deaths, serious illnesses, and injuries associated with the use of medical devices. An 

addendum lists safe practices for handling and operating oxygen equipment.

The USFDA and NIOSH both advised that the combination of aluminum oxygen cylinders and 

aluminum-bodied regulators pose an increased fire hazard. Both agencies have concluded that aluminum cylinders can be safely used with brass regulators. The Advisory does not discuss the safety of 

using steel cylinders with aluminum regulators. The flash fire experience suggests that the problem 

involves aluminum flakes being propelled from the cylinder into the aluminum regulator when the 

cylinder valve is opened rapidly.

The aluminum flakes ignite from the impact or heat of compression. The impact ignition occurs 

when the small metal flakes traveling at high velocities (often in excess of the speed of sound) collide with and come to rest on a surface. The energy produced from the collision raises the particle to 

ignition temperature. The flake may be consumed without further consequence or ignition of nearby 

materials may occur. With regulators constructed of aluminum, the burning flake can ignite another 

component or even the regulator’s body. The supply of high-pressure oxygen would allow the aluminum combustion to continue until the oxygen flow stops. Brass, being a more ignition resistant 

material, should tolerate the aluminum flake fires and contain them inside the regulator.

The Advisory recommends that aluminum-bodied regulators used with high-pressure oxygen be 

replaced with regulators made of brass. Until the regulators are replaced, users are referred to the 

recommendations in the safe practice section of the Advisory. Similar recommendations are included 

in the Contributing Factors section of this report.
18 U.S. Fire Administration/Technical Report Series

MAIntEnAncE

The first source of oxygen regulator maintenance information is the manufacturer. Their recommendations should be followed as a minimum. Some users have decided that an annual inspection 

and cleaning by a qualified oxygen regulator service center is beneficial. One purpose of the annual 

cleaning is to remove contaminants that may have collected metal flakes, particles from the cylinder’s 

valve seat, and other potentially combustible debris. Removing or reducing the amount of potential 

fuel inside the regulator limits the flash fire risk.

The annual inspection and cleaning should be done by an oxygen regulator service center because of 

the special cleaning materials needed and the likely need to partially disassemble the regulator.

C

The fire incidents described in the report include one or more of the following contributing factors. 

The construction materials of the regulators, valves, seals, and oxygen cylinders are not listed because 

flash fires have occurred with all types of construction. The following factors are issues to avoid:

•	 Internal hydrocarbon contamination of the regulator or regulator parts. Only equipment and parts 

designed for oxygen service should be attached to oxygen gas cylinders. Repairs to regulators and oxygen equipment must be done in clean facilities using tools cleaned for oxygen 

service. Store spare cleaned regulators in sealed containers such as a plastic bag to keep them 

free of dust, etc.

•	 Contamination of the surfaces and areas which mate the oxygen cylinder to the regulator with combustible 

materials. Example contaminants consist of dirty hands, cleaning solutions, dust, tape residue, 

and possibly skin oils and lotions. Protect spare cylinder valves with clean covers, caps, plastic 

bags, or plugs.

•	 The use of dirty tools and parts on oxygen regulators. Inadequate cleaning to remove combustible 

materials such as oils, greases, soldering flux, and solvent residues has contributed to the 

flash fire hazard.

•	 Equipment cleaning agents that have not been tested and found suitable for use with oxygen. Some agents 

may leave behind residues that could be dangerous and other agents may have limited effectiveness and may not remove all contaminants.

•	 Petroleum based lubricants. Such products must not be used on parts that come into contact with 

oxygen, especially high-pressure areas. Lubrication must be limited to special materials and 

is usually avoided in equipment used with used with pure oxygen.

•	 Internal contamination from metal particles and flakes from inside high-pressure cylinders and valves have 

accumulated on regulator filters. Inspection and maintenance of oxygen cylinder interiors should 

help to identify rust and corrosion that can be a source of particles and flakes. Rough handling 

and completely emptying cylinders can accelerate the production of such metal particles.

•	 The rapid opening of cylinder valves and the "on" position of flow regulators. High-pressure cylinder 

valves need to be opened slowly to bring the regulator’s internal parts to pressure slowly. 

Flow valves should be off or at the zero flow position. Doing so minimizes the heat of compression and allows the heat to dissipate before ignition temperature is reached.
USFA-TR-107/March 1999 19

Users of portable oxygen equipment should also review the following recommendations.

•	 NIOSH recommends that oxygen cylinders be stored upright to minimize the carry over of 

particles into the regulator. Placing the cylinder in the upright position is also recommended 

before opening the valve for the same reason.

•	 The selection and performance of non-metallic seals and gaskets has been identified as a fuel 

source for the flash fires. While not something the user can usually change, older cylinders, 

valves, and oxygen equipment may not employ the more ignition resistant materials.

•	 Point regulators away from the operator and patient when opening the cylinder valve. Do not 

look at the regulator's gauge until after the unit is pressurized.

•	 Before attaching the regulator to a fresh oxygen cylinder, open the valve slowly and briefly. 

This action is recommended to push out dust or other solid contaminants that my have collected or entered the cylinder valve's outlet.

•	 Removing the oxygen equipment form the ambulance or apparatus is recommended before 

conducting daily checkouts. Locate the oxygen cylinder and regulator in a clear area away 

from equipment and contamination. If a flash fire occurs, escape should be easier and exposure damage minimized.

•	 Specifications for new oxygen equipment should include requirements for using modern 

non-metallic seals and gaskets. Appendix A has references for evaluating these materials and 

they could be incorporated into equipment specifications.

L

1. The handling, storage, and use of oxygen equipment must minimize the possibility of 

contamination.

The types and sources of contamination which can cause flash fires in the oxygen equipment 

are varied and include materials which are considered noncombustible in normal atmosphere. 

In the list of materials are such items as clothing, valve seals, oxygen administration sets, bedding, and many metals especially when in the form of flakes or powder. Other sources are most 

lubricants, hydrocarbons, skin and hair oils, some lotions, and some soap residues. Handling 

of oxygen cylinders and regulators must avoid the contamination of mating surfaces and the 

introduction of foreign materials into the cylinder or regulator.

2. Oxygen equipment operating procedures and practices should minimize heat of compression buildup.

Cylinder valves should be opened slowly to allow pressure inside passages and the regulator 

to gradually increase. In addition to minimizing the amount of heat developed, this practice 

allows for heat dissipation within the regulator before the ignition temperatures of materials are reached. The oxygen flow valve should be set at zero (0) or not flow position before 

the cylinder valve is opened. By avoiding oxygen flowing through the regulator, the solid 

contaminants present will not migrate as far while the pressure increases and less heat is produced. Minimizing heat of compression eliminates a common ignition mechanism in oxygen 

equipment flash fires.
20 U.S. Fire Administration/Technical Report Series

3. Maintenance of cylinders, valves, and regulators should be done only by trained technicians 

using tools and facilities specially cleaned for oxygen service.

Equipment used with 100 percent oxygen, while usually rugged in appearance, is sensitive to 

conditions which might be overlooked by users not familiar with the fire hazards of oxygen. 

Knowledge of regulator operation and clean facilities and tools are needed to properly service, 

maintain, or test equipment. The manufacturer of the equipment is the first source of maintenance and testing information regarding frequency and what should be done. Because of the 

metal flakes and valve seal particles produced by typical operation of the oxygen cylinder valve, 

some users are cleaning or replacing the regulator’s inlet filter annually, even if not specifically 

directed to do so by the manufacturer instructions.

4. Some agencies are replacing aluminum-bodied regulators with units constructed with 

brass or nickel-plated brass bodies.

The USFDA, NIOSH, some gas distributors, users, and independent experts do not recommend 

the use of aluminum components in high-pressure oxygen equipment. This recommendation is based on 

high-pressure oxygen reacting vigorously with the aluminum promoting the ignition of the 

regulator’s body. Brass and nickel-plated brass do not react as energetically with oxygen as does 

aluminum. Regardless of the material the regulator is constructed of, the precautions described 

in the other lessons learned should still be followed. Contamination of pressurized brass-bodied 

regulators can also result in flash fires.

5. Users must recognize that oxygen cylinders have more than a single hazard which can cause 

serious injury.

Most equipment users recognize the hazard from the high-pressure gas inside the oxygen cylinder. The incidents of cylinder failure and valves being broken off resulting in the cylinder 

rocketing off are noted in many training programs. Oxygen-enriched atmospheres make ignition of combustible materials easier; cause a change in material combustibility; and increase the 

intensity of a fire when released. Liquid oxygen presents all of these hazards plus the hazards 

associated with cryogenic liquids.

6. Station uniforms and outer clothing made a difference on the amount of body burned and 

the severity of the burns received.

In several incidents the personnel involved with the flash fire were wearing flame or fire retardant station uniforms or a heavy cotton jacket. This clothing is credited with reducing the severity of burns and even preventing some burn injury. Personnel wearing simple cotton tee shirts 

seemed to have less serious burns than those wearing cotton/polyester blends or polyester 

clothing. Where medical exam gloves ignited, their presence usually increased the severity of 

burns on the hands. Because of the number of flash fires that occurred during equipment checkouts, personnel may consider wearing turnout gear, including clean structural gloves during this 

time. However, possible contamination of the oxygen equipment from this clothing should be 

analyzed.
USFA-TR-107/March 1999 21

7. Because of the danger from the remaining high-pressure oxygen, caution must be exercised 

while investigating and collecting samples of both the oxygen and damaged equipment.

Contamination has been a cause in many of the oxygen incidents in this report. Identification of 

the contaminant and its source is important for preventing future incidents. One possible contamination source is the oxygen gas inside the cylinder. Preferably a sample of the oxygen from 

the involved cylinder can be collected for analysis. The ability to take the sample could be limited 

as the cylinder may be damaged and its integrity suspect. To minimize the transportation hazard, 

investigators may want to discharge the oxygen before moving the cylinder. One alternative is 

to reduce most of the pressure but leave enough to sample the oxygen contents later. Another 

is to collect the sample while discharging the cylinder. Keeping the cylinder, control valve, and 

regulator clean during evidence collection and storage process is also an important step. Storage 

should be separate from other fire debris samples.
22

APPEndIX A

Additional Information

Readers can find more information about the hazards and precautions of using pure oxygen in the 

following:

Compressed Gas Association, Inc.

1725 Jefferson Davis Highway, Suite 1004

Arlington, Virginia 22202-4102

(703) 412-0900

Fax-on-demand (800) 827-5242

1998 Directory of Cleaning Agents for Oxygen Service

Standard C-6 Standards for Visual Inspection of Steel Compressed Gas Cylinders

Standard C-6.1 Standards for Visual Inspection of High-Pressure Aluminum Compressed Gas Cylinder

Standard E-4 Standard for Gas Pressure Regulators

Standard E-7 American National and CGA Standard for Medical Gas Regulators and Flowmeters

Standard G-4 Oxygen

Standard G-4.1 Cleaning Equipment for Oxygen Service

Standard G-4.3 Commodity Specification for Oxygen

Standard P-2 Characteristics and Safe Handling of Medical Gases

Standard P-2.5 Transfilling of High Pressure Gaseous Oxygen To Be Used For Respiration

Standard P-14 Accident Prevention in Oxygen-Rich and Oxygen-Deficient Atmospheres

American Society for Testing and Materials (ASTM)

100 Barr Harbor Drive

West Conshohocken, Pennsylvania 19428-2959

ASTMG 63-92 Standard Guide for Evaluating Nonmetallic Materials for Oxygen Service

ASTM G88-90 Standard Guide for Designing Systems for Oxygen Service

ASTM G94-92 Standard Guide for Evaluating Metals for Oxygen Service

“ASTM Committee G-4 Metals Flammability Test Program: Data and Discussion”: Stoltzfus, 

Joel M., Homa, John M., Williams, Ralph E., and Benz, Frank J.; Flammability and Sensitivity of Materials in 

Oxygen-Enriched Atmospheres: Third Volume; ASTM STP 986; D. W. Schroll, Editor; 1988, pages 28-53.
USFA-TR-107/March 1999 23

National Fire Protection Association

One Batterymarch Park

Quincy, Massachusetts 02269-9101

(617) 770-3000

NFPA 53 Guide on Fire Hazards in Oxygen-Enriched Atmosphere

NFPA 99, Standard for Health Care Facilities

Fire Protection Handbook, 17th Edition, Section 3, Chapters 6 and 15

Allied Healthcare Products, Inc.

1720 Sublette

St. Louis, Missouri 63110

(800) 231-5273

Urgent Devise Recall, Important Safety Information, May 20, 1997

United States Food and Drug Administration (USFDA)

Center for Devices and Radiological Health (CDRH)

Issues Management Staff

Office of Surveillance and Biometrics, HFZ-510

1350 Piccard Drive

Rockville, Maryland 20850

Fax: (301) 594-2968

Web Page: http://www.fda.gov/cdrh/oxyreg.html

Explosions and Fires in Aluminum Oxygen Regulators

Centers for Disease Control and Prevention (CDC)

National Institute for Occupational Safety and Health (NIOSH)

1095 Willowdale Road

Morgantown, West Virginia 26505-2888

Web Page: http://www.cdc.gov/niosh/fire/

Firefighter Fatality Investigation Report 98F-23, Oxygen Regulator

Flash Severely Burns One Firefighter – Florida
24

APPEndIX b

Compressed Gas Association Bulletins

Compressed Gas Association Bulletins are reprinted with the Association’s permission.
USFA-TR-107/March 1999 25

Appendix b (continued)
26 U.S. Fire Administration/Technical Report Series

Appendix b (continued)
USFA-TR-107/March 1999 27

Appendix b (continued)
28 U.S. Fire Administration/Technical Report Series

Appendix b (continued)
USFA-TR-107/March 1999 29

Appendix B (Continued)
30 U.S. Fire Administration/Technical Report Series

Appendix b (continued)
31

APPEndIX c

Recall Notice

The Response Line telephone numbers on the recall are incorrect. 

The voice line is (800) 216-4626 and the FAX number is (888) 231-5273.
32 U.S. Fire Administration/Technical Report Series

Appendix c (continued)
USFA-TR-107/March 1999 33

Appendix c (continued)
34 U.S. Fire Administration/Technical Report Series

Appendix c (continued)
USFA-TR-107/March 1999 35

Appendix c (continued)
36 U.S. Fire Administration/Technical Report Series

Appendix c (continued)
USFA-TR-107/March 1999 37

Appendix c (continued)
38 U.S. Fire Administration/Technical Report Series

Appendix c (continued)