The laboratory personnel had used an excessive amount of anhydrous ammonia because of a system malfunction. This extra draw on the 150 pound supply tank caused it to refrigerate and appear empty. By the time the mechanic came to fix the supply it had warmed up enough to build pressure back into the system. Relying on the laboratory’s description of an empty system the mechanic unscrewed a fitting that was under pressure. The anhydrous ammonia was released causing severe chemical burns and the unsecured cylinders caused significant property damage.

Consequences

• The injuries required skin grafts and burn treatment with two weeks of hospital stay. Several months of additional lost work time was needed.
• Medical bills, rehabilitation and compensation exceeded $60,000.
• The property damage was $180,000 including business interruption to another company during the evacuation.
• Additional untracked costs including the employee’s considerable pain and suffering, lost productivity of the laboratory and general lower moral of other employees.

Primary Causes
There were several underlying causes that contributed to the accident including:

• The laboratory personnel and the mechanic were not familiar with the refrigeration effect of the anhydrous ammonia.
• The mechanic was unfamiliar with compressed gas cylinders. He removed a fitting on the tank. The anhydrous ammonia was piped to the laboratory without a regulator, pressure gage or shut off valve. Only the fittings on the compressed gas tank were available for flow control of the gas.
• The anhydrous ammonia cylinder and the cylinders stored next to it were not secured from falling. The falling cylinders trapped the mechanic increasing the chemical burns and hampering the rescue effort.
• A face shield was not used as personal protective equipment.

Lessons Learned

• Assure that operating and maintenance personnel are trained and knowledgeable in the chemicals that they will be working with in the normal operations and during maintenance.
• Gas supply systems should be designed and installed only by qualified individuals.
• System designs and installations should be inspected to assure that they meet current regulations and industry standards.
• Employees should be trained in the proper use, storage and maintenance of compressed gas cylinders.
• Each job should be evaluated for proper personal protective equipment.

Actions Taken

• The company now uses MSDS and other chemical reference material to train all their employees for the chemical material used at that work site.
• This particular piping supply for anhydrous ammonia was re-designed and installed by a qualified contractor.
• This system and others at the facility were inspected by a safety consultant to assure that they met existing safety regulation and standards. As a result several other systems required re-design.
• Training for proper use, storage and maintenance of compressed gas cylinders are now part of this company’s annual training program.
• All the jobs in the facility were evaluated for proper personal protective equipment. A program is in place for assuring that employees use the equipment.

Reference for Safe Handling of compressed cylinders:
http://www.osha.gov/SLTC/compressedgasequipment/

Please contact an XL Insurance risk control consultant at +1 800-327-1414 if you have additional questions regarding these safety messages or other environmental, safety and health issues affecting your operation.

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For general information purposes only. Contents should not be construed or used as legal advice or opinion.

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