Nearly a year before 34 people were killed in a fire aboard the dive boat Conception, a second vessel owned by the same charter company began a three-day voyage around the Channel Islands.

Divers on the Vision charged numerous lithium-ion batteries installed in cameras, phones, computers and even underwater scooters with an array of power outlets in the salon area. At some point, one of those batteries began to smolder as it was charging. An alarmed crew member quickly tossed it into the water, preventing the fire from spreading, a witness and several sources told The Times.

The fire underscored the potential dangers of such batteries, which have been banned from cargo areas of commercial planes and become the subject of tighter regulations by the U.S. Navy.

But the U.S. Coast Guard didn’t sound major alarms about the fire risk of the batteries until after the Labor Day fire aboard the Conception, the worst maritime disaster in modern California history.

Read the full story on LATimes.com.