Interview with Howard Mavity, Partner, Fisher & Phillips LLP

Chem.Info's recurring Safety Scene feature focuses on how to improve safety in processing plants. In this installment, we looking at explosion hazards facing processors, what the fallout of an industrial explosion can be and what processors can do to mitigate their risks. We spoke with Howard Mavity of the law firm Fisher & Phillips about industrial safety.

Q: What factors present the greatest threat of explosion within processing plants?

A: First, manufacturers face Industry setting challenges.

Since the catastrophic Imperial Sugar explosion (where I was onsite for the first seven days) most food processors recognized some potential for combustible dust explosions and "deflagration," which refers to the catastrophic pressure wave caused by the startled cloud of dust triggered (and ignited) by the initial explosion. However, so many factors are at play that even comparable "baking" facilities may present widely varying amounts of problems, or none at all.

Likewise, "breading" processes and powdered beverages may present significant risks, and properly stored silos of sugar raise little concern. My point is that few safety and production subjects depend more on the specific facts.

One point is clear: almost every food processor which uses or generates small particles should conduct a Process Hazard Analysis (PHA) to determine hazards, and if necessary, solutions.

Second, manufacturers face  operational challenges

An attitude of "we've never had a problem before" is a significant problem. Processors would do well to remember that the sugar refinery had gone over 90 years without an event... until one factor changed. Many food processes and equipment have not changed in many years, and combustible dust control was not the manufacturer's concern when they were developed.

"Management of Change" is my largest concern. Many are aware of Process Safety Management (PSM) related to certain refrigeration and freezer processes. But they have not stopped to consider the role of unintended consequences in the context of combustible dust hazards. According to public accounts, a number of factors changed at the sugar plant, but one much discussed change was the addition of more enclosure of conveyors in response to food safety concerns. Combustible dust explosions require certain factors to be present: proper material and particle size, oxygen, ignition source and containment. A processor may make changes that seemingly have nothing to do with safety, only to change the combustible matrix.

All facts of food processing and its vendors and contractors display considerable ignorance of combustible dust hazards and applicable National Fire Prevention Association (NFPA) consensus standards.

A processor may assume that a trusted vendor or contractor will consider combustible dust when changing or installing lines and equipment, but that assumption may be misplaced. More worrisome is the fact that internal engineering and maintenance may have made modifications for years to lines and equipment; again with no specific consideration of combustible dust. This process also generates many problems with guarding, interlocks, e-stops and lock-out procedures.

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