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Consumer panel calls for flame arresters on gas cans after NBC report

In response to an NBC News investigation, the Consumer Product Safety Commission on Thursday called for manufacturers to add flame arresters to plastic gas cans to help prevent gas vapors from triggering explosions that can severely burn those handling the containers. “CPSC believes,” the commission said in a statement, “that this technology … should be included in gasoline containers.”

In response to an NBC News investigation, the Consumer Product Safety Commission on Thursday called for manufacturers to add flame arresters to plastic gas cans to help prevent gas vapors from triggering explosions that can severely burn those handling the containers. 

“CPSC believes,” the commission said in a statement, “that this technology … should be included in gasoline containers.”

The CPSC’s statement represents a change of position for the agency, which two years ago declined to issue a regulation either prohibiting or requiring the use of flame arrestors in portable consumer gasoline containers in response to a request from an industry trade group. [attachment: industry petition to CPSC] . At the time, the commission said the trade group had not provided “sufficient information to show that a rule is necessary.” 

CPSC issued the statement in response to inquiries by NBC News about a rare but real hazard: exploding gas cans.

An NBC News investigation reported Wednesday that scientific tests have shown that the gas vapor mixtures inside portable plastic gas cans can explode under certain limited conditions.

As part of the investigation, scientists at a combustion lab at Worcester Polytechnic Institute (WPI) in Massachusetts replicated tests they previously had conducted for an industry standards group, demonstrating how cans can explode.  

Flame arresters are pieces of mesh or disks with holes which, according to basic fire science principles, can prevent flame from passing through by absorbing and dispersing heat.

They are in use in metal “safety” gas cans used in many workplaces, in fuel tanks and storage systems, and in storage containers for other flammable liquids, such as charcoal lighter fluid and bottles of rum.

Over the past two decades, there have been at least 80 product-liability lawsuits filed on behalf of people injured or killed in incidents allegedly involving gas can explosions.  The lawsuits argue that plastic gas cans are “dangerous” and “defective,” and are “susceptible” to so-called “flashback” explosions of gas vapor mixtures inside the cans because they do not have flame arresters.  The lawsuits blame the absence of flame arresters as a cause of the alleged explosions and the injuries.

At NBC News’ request, the Consumer Product Safety Commission reviewed injury reports in federal databases and found reports of at least 11 deaths and 1,200 emergency room visits since 1998 involving reported explosions of gas cans while consumers were pouring gasoline from them.

"Respected researchers have proven that flammable mixtures of oxygen and gasoline vapors can exist in gasoline containers, especially when there are small amounts of gas in a large container,” the CPSC statement read.  “And, under certain circumstances, the vapors can ignite and cause a gas can to explode. The results can be deadly or life-altering.

“CPSC is calling on the industry to regain the momentum that was lost in years past by designing their products to include this safety technology.  In addition, CPSC is asking voluntary standards organizations to incorporate a flame arrestor system into applicable safety standards for gas cans.”

The industry’s trade group, the Portable Fuel Container Manufacturers Association (PFCMA), also issued a statement saying that it would be premature to add flame arresters. 

“Because gasoline is an inherently dangerous product, it is important that any design changes increase, rather than decrease, the safety of gas cans, which are used by consumers over 3 billion times each year,” the statement read. “It is never safe to mix gasoline and fire and no device will ever make it safe to misuse the product by exposing gasoline to flame or other ignition sources.”

“… It would be irresponsible to incorporate flame arrestor technology as we understand it today in either our products or the voluntary standards governing our products before it is proven to be effective and safe,” the statement said.  “If a new safe and effective standard is promulgated, the industry will embrace it.”

The plastic gas can industry has argued that its cans are safe despite not having flame arresters, and that most explosions occur because of consumer misuse and negligence, such as pouring gasoline from a gas can to start or enlarge a fire. 

Some fire-science experts have told NBC News explosions of gas vapor mixture inside the can, under pressure, is more likely to spray flaming gas vapor and droplets with force, and cause catastrophic injuries. 

The CPSC statement was welcome news to individuals who have suffered severe burn injuries in incidents involving gas can explosions. 

“The CPSC announcement means everything,” Diane Breneman, a plaintiff attorney who has represented 30 people injured in alleged gas can explosions,said in an email to NBC News, “as does WPI admitting the cans have a problem that needs to be addressed.  My phone has been ringing off the hook with crying clients and families.” 

The industry trade group’s statement noted that ASTM International, the industry technical standards group, “is in the process of testing potential solutions,” and had hired WPI to conduct a three-phase scientific study “to understand if there is a way to safely and effectively incorporate flame arresters into gas cans.”

On Tuesday, ASTM and WPI released data from a second phase of the study, which tested 12 flame arrester designs from six gas can manufacturers. The results of those tests showed that four designs passed, preventing the flashback of flame into cans, but that seven failed. 

According to the scientific testing, flashback explosions can occur if gas vapor escaping a can through an open spout contacts a source of ignition such as a flame or spark. If the vapor ignites, and if the flame travels back through the spout, and if the gas/air vapor mixture inside the can is a certain concentration, then that mixture inside the can can ignite, and explode inside the can.  The lawsuits have alleged that flashback explosions inside the cans have caused the cans to rupture with force, spraying fireballs of flaming gas vapor and liquid.

WPI’s tests and other previous scientific tests show such explosions happen only under certain limited conditions, with the highest risks involving extremely low volumes of gasoline in the cans, cool temperatures, and a common pouring angle of 42 degrees. 

Despite the CPSC’s change of position, its new statement did not indicate that the commission is considering a government regulation requiring flame arresters on cans. 


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And the industry trade group’s statement described the CPSC’s statement as “expressing a desire” for the addition of flame arresters to cans and for the addition of requirements for them in voluntary technical standards for the cans. 

According to the Consumer Product Safety Act, the CPSC can issue a regulation only under qualified circumstances.  Before issuing a regulation, a previous CPSC report on gas cans stated, CPSC “must find that the rule is “reasonably necessary to prevent or reduce an unreasonable risk of injury” and it is in the public’s interest.  The commission must also find that the benefits of the rule bear a reasonable relationship to the costs and that it is the least burdensome way to reduce or prevent the risk of injury.  If there is an applicable voluntary standard, the commission must also find that the voluntary standard is not likely to eliminate or adequately reduce the risk of injury or that substantial compliance with the voluntary standard is unlikely.”

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