WASHINGTON - A massive explosion and fire at the CAI/Arnel ink and paint products manufacturing facility in November 2006 occurred because CAI lacked safeguards such as alarms and automatic shutoffs that would have prevented a 10,000-pound mixture of flammable solvents from overheating in the unattended building, investigators from the U.S. Chemical Safety Board (CSB) said in a final draft report. 

Steam heat to the mixing tank was most likely inadvertently left on by an operator before he left for the day. As the temperature increased, vapor escaped from the mixing tank, built up in the unventilated building, ignited and exploded.  

CSB investigators said that ink manufacturer CAI did not follow regulations or appropriate good practices for the handling of flammable solvents. The CSB report proposes changes to national fire codes and to state licensing and inspection procedures to improve the safety and oversight of facilities handling hazardous materials.