The Office of the State Fire Marshal is still investigating the cause of Wednesday night's explosion at Aspen Aerogels in East Providence.
Eleven employees were taken to the hospital for evaluations after the blast and they have since been released.
While the exact cause is not known, East Providence Mayor Bob DaSilva says it appears that a 60-foot-long insulation oven may be to blame.
He says the oven is in pieces and investigators believe that's the origin point.
The Occupational Safety and Health Administration is also investigating the blast.
(Photo: RI Fire Marshal's Office)