Exploding e-cigarettes have led to dozens of lawsuits, The Wall Street Journal reports. Lawyers say the explosions are caused by cheaply made lithium-ion batteries.

Experts hired by plaintiffs say the batteries can lack controls that prevent overcharging or discharging to a voltage that is too low, leading to an explosion. The batteries also may not have a hollow center core to allow gas to escape slowly, the experts say.

E-cigarette industry groups say there are few such explosions, and that accidents are often caused by user error, the article notes.

Many of the batteries cited in lawsuits are made by Chinese companies, which are difficult to sue in U.S. courts. As a result, lawyers often name everyone in the e-cigarette supply chain as defendants.

In October 2015, the Department of Transportation announced it was banning airline passengers from packing e-cigarettes and other battery-operated electronic smoking devices in their checked bags because of the risk of fires.

The ban was prompted by reports of incidents in which explosions or fires on planes have been caused by e-cigarettes. In several cases, the devices were packed in luggage. In most instances, the devices were accidentally left on, or the battery short-circuited.