The investigation into what caused a deadly explosion at Tennessee plant could last for days. Here’s what we know

(CNN) — Nearly three days after a massive blast at a Tennessee facility that specialized in making military explosives, investigators are still combing through the site where 16 people were killed in a “mass detonation” so significant experts say it produced seismic readings hundreds of miles away.

Investigators from multiple agencies, including the FBI, are assisting in the response to recover remains for DNA testing, which will likely span days, officials have said. No one has been found alive during the complex search, according to Humphreys County Sheriff Chris Davis. The cause of the explosion remains under investigation, authorities said.

Meanwhile, residents are undergoing a “gauntlet of emotions,” Davis said, as Friday’s blast brought painful memories of tragedies that traumat