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

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 it produced seismic readings hundreds of miles away, experts say.

​ 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 it produced seismic readings hundreds of miles away, experts say. Read More Breaking News, Latest News and Videos | CNN