NEW YORK, USA (AP) — Katrina Williams wanted a safer alternative to smoking, and e-cigarettes seemed to be the answer until the day one exploded in her pocket as she drove home from a beauty salon.

“It was like a firecracker” as it seared third-degree burns in her leg, blasted through her charred pants and stuck in the dashboard, the New Yorker said. That was in April. Williams, a freight manager, said she still hasn’t returned to work. “It was very disturbing.”

Similar painful accidents have been recorded with increasing frequency over the past year as use of e-cigarettes has climbed, with faulty batteries seen as the suspected culprit. The industry maintains e-cigarettes are safe when used properly.

The US Food and Drug Administration, which started regulating e-cigarettes in May, identified about 66 explosions in 2015 and early 2016, after recording 92 explosions from 2009 to September 2015.

In late November, a clerk at a liquor store in New York’s Grand Central Station was casually leaning against a counter when the e-cigarette in his pocket erupted. A security camera captured him frantically trying to snuff out a fountain of white-hot sparks.

Surveillance video also captured an e-cigarette explosion in September at a New Jersey mall that left a woman’s Louis Vuitton bag smoking as she stood at a checkout counter.

Police say a teenage girl on a train at the Universal Orlando amusement park suffered burns in October when an electronic cigarette belonging to another visitor exploded and shot a fireball at her.

The numbers kept by the FDA may be an undercount. One hospital, the UW Medicine Regional Burn Center at Harborview Medical Center in Seattle, says it has seen about 23 patients with e-cigarette burns since it started tracking them informally in October 2015.

“They are extremely dangerous and need to be revamped or revised,” said Marc Freund, a New York attorney who represents both Williams and a 14-year-old boy who was partially blinded when an e-cigarette device exploded at a kiosk selling e-cigarettes at a Brooklyn mall.

The problems with the devices are linked to their lithium-ion batteries, which help vaporise liquid nicotine into a mist that distributors and some health experts say is far less harmful than traditional tobacco cigarettes.

The same types of batteries are used safely in many consumer electronics, but they’ve also been behind fires in hover boards and smartphones. Last year, the federal Department of Transportation issued a rule prohibiting passengers from packing e-cigarettes in checked luggage to protect against in-flight fires.

Thomas Kiklas, co-founder of the Tobacco Vapor Electronic Cigarette Association, argues the devices are safe when used properly. He said the TVECA encourages proper recharging of the batteries as a way to prevent possible injuries.

Euromonitor International, a market research company, noted there were 10.8 million regular e-cigarette users in the US in 2015, generating $3.5 billion in sales.

Gregory L Bentley, an Irvine, California, attorney, won a nearly $2 million judgement in a product liability lawsuit for a woman burned by an e-cigarette last year. He said he has a growing list of similar cases, most of which involve batteries and other components manufactured in China that have been subject to little safety oversight.

“The problem is defectively manufactured batteries,” he said. “Consumers need to know it’s next to impossible to sue a Chinese company. If people want to seek compensation they have to target distributors, wholesalers and retailers.”

Last week, the US surgeon general called e-cigarettes an emerging public health threat to the nation’s youth, although he highlighted the risk of nicotine addiction, not explosions.

New York Sen Charles Schumer said the FDA should consider a recall.

“It’s bad enough that e-cigarettes cause nicotine addiction and may be dangerous to a person’s health, but now it seems they’re doubling as a ticking time bomb,” he said.

FDA spokesman Michael Felberbaum said the agency is reviewing the health impacts of all tobacco products, including e-cigarettes. He said the review will include an evaluation of the use of e-cigarette batteries, including “amperage, voltage, wattage, battery type” and other issues.