Here’s What Happened:

Chlorine was being transferred from a railroad tank car when the transfer hose burst. Both automatic and manual emergency shutdown systems failed so the release was unabated for about three hours. Approximately 48,000 pounds (21,800 kg) of chlorine escaped before emergency responders were able to stop the release. They entered the chlorine cloud wearing “Class A” safety gear and climbed on top of the car to close the manual shut off valves. Near by neighbors either evacuated or “sheltered-in-place.” The adjacent Interstate was closed to traffic for 1 1/2 hours. Of the 63 people that sought medical evaluations due to respiratory distress, 3 were hospitalized. The release also damaged trees and other vegetation in the area.

How Did this Happen?

• The ruptured hose should have had an inner Teflon liner reinforced with a Hastelloy C-276 exterior metal braiding. Instead, the exterior metal support braiding was stainless steel and was easily corroded by chlorine permeation through the Teflon liner. The hose failed after less than 2 months of service.
• Both the purchase and shipping papers indicated that the hose was constructed of the proper materials, but it was not tested or verified upon receipt.
• An emergency shut down system activated by an employee before evacuation failed to work because of severe build up on the valve ball.

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