Date of incident: April 2013
Notice of incident number: 2013165590435
Employer: Manufacturer of industrial gases

Incident summary
A worker was moving two full medical-grade oxygen cylinders to place them in a storage rack. One of these aluminum cylinders knocked against a freestanding cylinder on the ground, which then exploded. The regulator and valve assembly separated from the cylinder body, and part of the side wall near the top of the cylinder ruptured, injuring the worker.

Investigation conclusions

Cause

• Contaminant in the presence of compressed oxygen: In the area of the valve's O-ring, a contaminant - an organic compound combined with a synthetic lubricant - ignited. The internal flash fire, fuelled by the compressed oxygen, caused the side wall near the top of the cylinder to rupture and the regulator and valve assembly to separate from the cylinder.

Underlying factor

• Contact between two full oxygen cylinders during handling: The incidental contact between two full oxygen cylinders and/or the impact of the cylinder on the ground as it fell introduced oxygen into an area of the valving where a contaminant was present, initiating a flash fire.

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