Oxygen firebreak

Oxygen is not flammable, but when it is present in increased concentrations it will enable fires to start much more easily. Once a fire has started, if supplemental oxygen is present it will burn more fiercely, based on the principle of the fire triangle. Materials that do not burn in ambient air may burn when there is a greater concentration of oxygen present than there is in air.

Most home oxygen fires are caused by patients smoking whilst using medical oxygen.[1] Despite the inherent dangers, researchers estimate that between 10 and 50 per cent of home oxygen patients continue to smoke.[2] Other sources of naked flames, such as gas flames and birthday candles, can also pose a risk.[3]

Once a fire has started in the patient's nasal cannula it will track back towards the oxygen source and if not stopped may lead to a ‘whole house’ fire. Whole house fires are directly correlated with single or even multiple deaths. According to the US National Fire Protection Association (NFPA), 25% of oxygen fires get beyond the immediate surrounding area to become ‘whole house’ fires.[4]

While an oxygen firebreak / thermal fuse cannot stop the initial ignition, it can limit the potential for whole house fires, more serious injury and death. Firebreaks / thermal fuses can also buy more time for a patient and other individuals in the building to escape, and limit the material cost of fire damage.

A study, The prevalence and impact of home oxygen fires in the USA, published in September 2019, analysed media reports of home oxygen fire incidents between December 2017 and August 2019. The report found 311 incidents, resulting in 164 deaths, equivalent to one patient death every four days. It also found that a third of reported incidents referenced exploding cylinders, posing a significant risk to third parties, including emergency services. The estimates that there are between 100 and 150 deaths every year from home oxygen fires in the US, describing it as a ‘material health issue’.

In 2008 the NFPA published a report suggesting that there are 46 deaths each year in the US from 182 fires. The report also stated that US hospital emergency rooms deal with an average 1,190 cases of burns each year as a result of home oxygen fires. However, the NFPA describes these statistics as "likely underestimates".[5]

Further analysis by Marty Ahrens on behalf of the NFPA in 2017 recorded a likely average annual death rate for home fires involving oxygen administration equipment of 70 people (or 3% or all home fire deaths), based upon figures between 2011 and 2015. The report also suggested that these fires or burns are becoming more common.[6] In 2019 the NFPA also reported that "medicinal oxygen was involved in 13% of the home smoking material fire deaths".[7]

The United States Fire Administration (USFA) said in a 2015 report that "While no one factor is solely responsible for the increased fire risk to older adults receiving home health care, smoking in the presence of oxygen is recognized as one important problem."[8]

A study of home oxygen therapy patients in the Veterans Health Administration between 2009 and 2015 examined 123 cases of reported adverse events related to flash burns. It found that 100 cases (81%) resulted in injury, and 23 (19%) resulted in death. Although 89% of veterans claimed to have quit smoking, 92% of burns occurred as a result of smoking.[9]

Not all European countries monitor data on the number of fires that occur as a result of home oxygen. Despite a European Union Medical Device Directive requiring incidents to be reported to national vigilance authorities, there is often inadequate coordination to publish the information centrally.[10] According to the German Federal Institute for Drugs and Medical Devices (Bundesinstitut fur Arzneimittel und Medizinprodukte, BfArM) it is likely that such incidents are grossly under-reported.[11]

In England and Wales, central reporting of adverse incidents is a requirement of the NHS Service Specification for Home Oxygen. After firebreaks became mandatory in 2006, the average number of deaths by fire was 0.36 per thousand patients per year. In the US, where firebreaks were not required, almost twice as many patients (0.62 patients per thousand) died.[12] A Freedom of Information request in 2018 revealed that only fatality relating to home oxygen fires was recorded in the five-year period between 2013 and 2017.[13]

In 2018, a Freedom of Information request to all Clinical Commissioning Groups in England (where firebreaks are mandatory) revealed that during the five years between 2013 and 2017 inclusive, 63 serious incidents involving oxygen fires were recorded and just one fatality. 73% of CCGs, representing 71% of patients in England, responded to the request. When the results are extrapolated to cover the whole patient population of 81,000, the figures are 89 incidents and 1.4 deaths.[14] The fatality rate is significantly lower than any other previous study in the UK or internationally, and significantly lower than rates in the US or Japan where, compared with the equivalent patient population, they were 27 and 14 respectively.[15] The White Paper report suggests that the mandatory introduction of firebreaks, in conjunction with a "multidisciplinary approach to patient education", as well as risk assessments, is responsible for the low level of fatalities.

Some of the incidents involving deaths and injuries to patients, their relatives, fellow residents, as well as firefighters include:

Richmond, Indiana, US. November 19, 2018

Two people were killed and six injured in an apartment complex fire, 48 year old Andrew Thornburg and 56 year old Richard Wilkinson. A number of senior citizens live in the apartments many of whom use walkers and wheelchairs making the task of evacuating the residents harder for fire crews. The fire is believed to have been caused by 'smoking materials', with many of the residents understood to be home oxygen users." [16]

Tilford, South Dakota, US. September 7, 2018

43 year-old firefighter David Fischer was killed when a propane tank exploded during a fire. Home oxygen patient Raymond Joseph Bachmeier (82) was also killed in the incident. Authorities said that the fire was caused by "a cigarette being smoked in bed while on oxygen." [17]

Fayetteville, Arkansas, US. July 14, 2018

An explosion at a house left a 69 year old man dead. The man's daughter reported that he had been smoking near his oxygen concentrator.[18]

Marion County, Indianapolis, US. May 19, 2018

A man died in a fire which is believed to have started after he was smoking near an oxygen cylinder.[19]

San Remo, Italy. March 23, 2017

A woman died in a fire which started while she was smoking and simultaneously using her oxygen cylinder. Her husband also died trying to escape the blaze.[20]

Pont-Sainte-Maxence, Oise, France. March 11, 2017

A 60-year-old wheelchair-bound patient, described as a 'big smoker', died when his liquid oxygen dewar exploded following a nighttime fire in his apartment. His wife also suffered injuries.[21]

Pau, France. February 19, 2017

A patient died and an apartment was destroyed after medical oxygen cylinders exploded, leading to a fire. Fifteen other residents had to be relocated after the incident.[22]

Winchester, Kentucky, US. March 11, 2016

Patient Jackie Hisle Jr. was sentenced to ten years’ imprisonment on three counts of manslaughter after an incident in which his son, Donald Hisle, and two other residents were killed and six others were injured. Mr Hisle Jr. was smoking while using an oxygen concentrator, despite warnings.[23]

Knox County, Tennessee, US. February, 2012

A jury awarded $2.5 million in damages against Apria Healthcare after the death of 72-year-old Jimmy Kelley from Knox County. The award was reduced to $1.275 million after the jury found Kelley to be partly responsible. Mr Kelley, a smoker, also used a space heater in a camper van where oxygen cylinders were stored.[24]

The World Health Organization recommends ‘firebreak connectors to stop the oxygen flow in the event of fire’ in all oxygen concentrators.[30]

Three main standards cover the use of oxygen firebreaks / thermal fuses:

• ISO 8359:1996/Amd.1:2012: Oxygen concentrators for medical use. Safety requirements

The safety requirements for oxygen concentrators are governed by the amended standard ISO 8359:1996+A1:2012. The US FDA recognized the standard from January 2014. In January 2015, it was superseded by ISO 80601-2-69:2014. Health Canada, which is responsible for national public health, still recognizes the standard.

• EN ISO 8359:2009+A1:2012: Oxygen concentrators for medical use. Safety requirements

All of the 28 CEN (European Committee for Standardization) national standardization bodies (NSBs) have published EN ISO 8359:2009+A1:2012 as national standards. In Europe EN ISO 8359:2009+A1:2012 has harmonized standard status, which triggers ‘presumption of conformity’.

• ISO 80601-2-69:2014: Medical electrical equipment – Part 2-69: Particular requirements for basic safety and essential performance of oxygen concentrator equipment

Included in ISO 80601-2-69:2014 are specific requirements that serve to mitigate the risk of fire related to oxygen therapy. The requirements state that the following should be provided:

1. A means to extinguish a tubing fire and isolate the oxygen flow in the accessories (nasal cannula and tubing or mask and tubing). The standard states that this should be fitted close to the patient.
2. A means to prevent the fire spreading into the oxygen concentrator outlet. The standard states that the means can also stop the flow of oxygen although it is not required to do so. It also specifies that if a bubble humidifier is fitted to the concentrator, that the means must also protect the bubble humidifier.