The question that lingers in the wake of the Samsung Galaxy Note 7 debacle—just why did all those batteries start exploding?—has yet to be answered. And even after the company permanently halted production of the device on Tuesday, Samsung still doesn’t know what really happened. Hundreds of engineers at the company have been furiously conducting tests over the lat month and have been unable to reproduce the problem, reports the New York Times.
When it first issued a recall in early September, Samsung said that “we conducted a thorough investigation and found a battery cell issue.” But it didn’t provide any more info when it announced the end of production this week. And one expert, Park Chul-wan, the former director of the Center for Advanced Batteries at the Korea Electronics Technology Institute, told the Times after reviewing documents and interviewing dozens of engineers, “I think there was nothing wrong with [the batteries] or that they were not the main problem.”