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JBSA News
NEWS | Aug. 27, 2015

E-cigarettes and explosions: An emerging danger

Joint Base San Antonio-Lackland fire emergency crews recently responded to an alarm activation in a base housing area. Upon arrival, fire alarms were sounding and the facility was being evacuated. The initial report indicated a smoke detector had been activated within the facility.

After inspection, it was found an individual smoking an e-cigarette caused the smoke detector to go off. With these items now in regular use almost everywhere, it presents a new problem to firefighters and users alike.

Although fires and explosions caused by electronic cigarettes are rare, according to an article published by the U.S. Fire Administration in October 2014 (http://www.usfa.fema.gov/prevention/outreach/smoking.html), more than 2.5 million Americans are using them and this number is growing rapidly.

The article states that 25 separate incidents of explosion and fire involving an e-cigarette were reported in the United States media between 2009 and August 2014, resulting in nine injuries, two being serious burns when the devices exploded in the user’s mouth. In addition, 20 of the incidents occurred while the battery was charging. It’s likely that there were additional incidents not reported to the fire department and/or reported in the media.

The e-cigarette, also called a personal vaporizer or electronic nicotine delivery system, is a battery-powered device that simulates tobacco smoking by producing a heated vapor which resembles smoke. These devices have become an alternative to smoking, including among a growing number of individuals who have never been smokers, but who enjoy the many flavors and/or the experience of using e-cigarettes.

Patented in 2003, e-cigarettes have been sold in the U.S. since 2007. According to a 2014 Department of Family and Preventative Medicine at the University of California, San Diego (http://tobaccocontrol.bmj.com/content/23/suppl_3/iii3.short) there were 466 brands of e-cigarettes and 7,764 unique flavors available for sale. They also state the number of products has been increasing at a rate of 10.5 brands and 242 new flavors per month.

Annual e-cigarette sales have reached $2.5 billion dollars nationally and the Statistic Brain website (http://www.statisticbrain.com/electronic-cigarette-statistics/) reports that as of July 13, 2014, there were 2.5 million e-cigarette smokers in America.

The devices have a heating element (an atomizer or cartomizer) which vaporizes a liquid solution. Solutions (also called “juice”) usually contain a mixture of propylene glycol (which increases flavor), vegetable glycerin (which increases vapor), nicotine and flavorings. Some juices provide flavored vapor without nicotine.

“Automatic” e-cigarettes activate the heating coil when a user takes a drag from the device. Manual e-cigarettes have a switch that the user depresses to energize the heating element to make the heated vapor.

Most manufactured devices have built-in timeout features that prevent overheating and many have locking features to prevent the switch from being activated in a pocket or purse. A light-emitting diode to simulate a cigarette’s glow on the end is also common in e-cigarettes.

Media reports generally characterize these incidents as explosions. The event occurs suddenly and is accompanied by a loud noise, a flash of light, smoke, flames and often vigorous ejection of the battery and other parts. Many of the media reports state that the battery or other components of the device were ejected under pressure and “flew across the room,” often igniting combustible items where they landed.

Most of the incidents resulted in ignition of nearby contents, such as carpets, drapes, bedding, couches or vehicle seats. Users were usually nearby when the incident occurred and they were able to extinguish the fires while they were still small. One incident resulted in the loss of a bedroom.

Eighty percent of the incidents reported occurred while charging. A variety of charging sources were reported, such as laptop universal serial bus ports, auto USB adapters, desktop computer USB ports and wall adapter USB ports.

Not all USB ports are created equal, as the voltage and current provided by USB ports can vary significantly. As a result, plugging an e-cigarette into a USB port or power adapter not supplied by the manufacturer may subject the battery to higher current than is safe, leading to thermal runaway that results in an explosion and or fire.

Concern has been raised that the heating element inside the e-cigarette could become an ignition source. Manufactured personal vaporizers typically have built-in circuits to limit the time that the heating element can be turned on, which prevents overheating and possible fires or injuries.

In the absence of independent safety testing of the e-cigarettes, no assurance that these circuits will reliably perform their safety function is available.

E-cigarettes are increasingly common and sales are growing rapidly. The lithium-ion batteries used to power the devices can fail. Battery failures, manifested as small explosions and fires, have occurred. Considering the vast number of products in the field that use lithium-ion batteries, however, it is clear that the failure rates are low.

For more information on smoking and fire safety, visit www.usfa.fema.gov.

(Sources: U.S. Fire Administration; Department of Family and Preventative Medicine at the University of California, San Diego; Statistic Brain; Federal Emergency Management Agency; Ricardo S. Campos, Joint Base San Antonio public fire and life safety educator, also contributed to this article.)