A federal chemical safety investigation team will examine the factors that led to an accidental release that occurred on September 20 at the BP Toledo Refinery in Oregon, Ohio.

A team from the U.S. Chemical Safety Board (CSB) deployed shortly after the release. The incident included an explosion and fire that resulted in two fatalities, the release of sulfur dioxide and hydrogen sulfide, and significant property damage.

“The CSB team will be documenting the site, gathering evidence and initiating information requests as we begin our investigation into this tragic incident,” said CSB Interim Executive Steve Owens.

According to a report, BP has not said what caused the fire, and there was no word on the extent of the damage. The refinery can process up to 160,000 barrels of crude oil per day.

The CSB is an independent federal agency charged with investigating incidents and hazards that result, or may result, in the catastrophic release of extremely hazardous substances. CSB investigations look into all aspects of chemical accidents and hazards, including physical causes, as well as inadequacies in regulations, industry standards and safety management systems.