An explosion last year at an area Barton Solvents distribution plant most likely was caused by a static spark from a loosely held measuring float, investigators said Thursday.


An explosion last year at an area Barton Solvents distribution plant most likely was caused by a static spark from a loosely held measuring float, investigators said Thursday.

Such floats are used in hundreds of thousands of chemical tanks around the world, according to investigators.

The U.S. Chemical Safety Board, an independent federal agency charged with investigating industrial chemical accidents, released its final report Thursday on the July 17, 2007, explosion at the Barton Solvents plant in Valley Center.

The report said several factors came together to lead to the explosion: the right temperature and humidity, the metal measuring float, how the tank was filled and refilled, and the ignitable vapor-air mixture inside the storage tank.

The blast destroyed much of the plant and led to widespread evacuations of Valley Center. Eleven residents and one firefighter were injured.