CTA Report, Draft 1, ISP Review - US Chemical Safety and Hazard ...

8.7 Incident Investigations
The incident investigation program at CTA did not ensure that all incidents were investigated or that
corrective actions were taken. CTA used a “fire report” for documenting fires. The report was filled out
by supervisors and sent to the safety department. In the 7 months prior to the February 20 incident,
reports were filed for nine fires on the production lines—three of which involved the line 405 oven.
However, CSB interviews with employees revealed that these reports did not account for all fires.
Employees told CSB investigators that numerous small fires took place on the production lines. Most
fires occurred in the ovens, which provided radiant heat but did not normally contain flames. Fires
erupted when deposits of combustible material built up and ignited. The ovens had permanent openings
on each end to allow for the product to move through on a conveyor; therefore, flames from these fires
sometimes escaped into the work area.
Employees working on line 405 reported that fires occasionally occurred in the forming hood next to the
oven. Some employees described the ignition of dust on the walls adjacent to the line 405 oven. One
employee on line 405 remembered an incident where the side of the oven and the floor under the line
caught fire. As the layer of dust burned, the fire spread toward the blend room, about 40 feet away. In
1979, another incident occurred on line 403 in a forming hood, severely burning two employees.
Four water hoses and several portable dry chemical extinguishers were mounted near the line 405 oven.
This equipment was needed to put out oven fires. CTA safety personnel estimated that oven fires occurred
on an average of once a week, based on the frequency of refilling extinguishers. This estimate did not
include the fires put out with water.
In the Accident Prevention Manual for Business and Industry, NSC (1997) notes that all incidents should
be investigated, and that “investigation or analysis must produce factual information leading to corrective
actions that prevent or reduce the number of incidents.” However, during the 7 months prior to the
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