Washington, DC, May 22, 2006 - A team of investigators from the U.S. Chemical Safety Board (CSB) has begun an assessment of the May 20 explosion and fire at the Valero St. Charles refinery in Norco, Louisiana, 15 miles from New Orleans.

The explosion late Saturday reportedly involved the refinery's diesel hydrotreater unit and caused no injuries; large portions of the 250,000 barrel-per-day refinery remain shut down.

CSB investigator John Vorderbrueggen will lead a team of four who will assess the circumstances of the explosion and recommend whether a further CSB investigation is warranted. Investigators began their work at the site on Monday afternoon.

CSB investigations of the root causes of accidents typically take 6 to 18 months to complete. The CSB is currently investigating a nitrogen asphyxiation incident at Valero's Delaware City (DE) refinery which killed two workers in November 2005.

The CSB is an independent federal agency charged with investigating industrial chemical accidents. The agency's board members are appointed by the president and confirmed by the Senate. CSB investigations look into all aspects of chemical accidents, including physical causes such as equipment failure as well as inadequacies in safety management systems, regulations, and industry standards.

The Board does not issue citations or fines but does make safety recommendations to plants, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA. Visit our website, www.csb.gov.

For more information, contact Director of Public Affairs Dr. Daniel Horowitz at (202) 261-7613 (office) or (202) 441-6074 (cell).