Chlorine Dioxide (ClO₂) Generation Fataility (Incompatibles and Combustible Dust Explosion)

At 4:30 p.m. on November 11, 2020, two (2) employees were in the process of producing batches of a chlorine dioxide generator inside a newly purchased mixer. Emplo yee #1 was killed in an explosion after closing the lid on the mixer to complete the mixing operations. Employee #2 was injured during the rescue attempt. The manufacturing room and the surrounding area sustained extensive damage.

On or about November 11, 2020 employees in the PV Room and in the areas surrounding the PV Room were exposed to chemical fire and explosion hazards associated with the manufacturing of a chlorine dioxide generator chemical product:

(a) The manufacturing process utilized mixing/blending equipment capable of producing significant friction despite the employer having information that:

(1) a combination of ingredient components (oxidizer with organic material) resulted in the hazard of a friction sensitive material, and

(2) other ingredient components were combustible dust capable of presenting the hazard of explosion when in a dense cloud form and subjected to an ignition source (such as sparks, embers, heat, flame) caused by friction.

(b) The manufacturing process utilized mixing/blending equipment capable of producing an internal dust cloud despite the employer having information that the chemical mixture and several ingredient components were combustible dust capable of presenting the hazard of explosion when ignited in a dense cloud form.

(c) The manufacturing process mixed a strong oxidizer ingredient component with several ingredient components known to be incompatible with the oxidizer despite the employer having information that these ingredient components were chemically incompatible, thus presenting the hazard of fire and explosion.

In addition, the mixing/blending equipment utilized lubrication oil, also incompatible, which was capable of coming into contact with the oxidizer ingredient component.

Abatement documentation is required for this item in accordance with the requirements of 29 CFR 1903.19(d). Among other methods, feasible methods of abatement include heeding the applicable warnings available to the employer through externally developed ingredient Safety Data Sheets (SDSs), the internally developed product SDS, the internally developed EPA pesticide master label for the product, and internally developed production procedures in order to develop and implement a production process that:

(1) Avoids or protects against the recognized hazard of oxidizer ignition from friction when incorporated with organic material,

(2) Avoids or protects against the recognized hazard of dust cloud formation in the presence of potential ignition sources such as friction and/or static electricity, and

(3) Avoids or protects against the recognized hazards of mixing and storing oxidizers with incompatible chemicals.

Perform a process hazard analysis (PHA) / dust hazard analysis (DHA) utilizing recognized risk assessment techniques such as those found in ANSI/ASSP Z690.3 “Risk Assessment Techniques”, NFPA 652 “Standard on the Fundamentals of Combustible Dust”, and NFPA 654 “Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids” in order to develop a manufacturing process free from or adequately controlling recognized hazards.

Consider production processes and technologies that may include, but are not limited to, concepts such as: segregation of incompatible materials, low energy mixing/blending processes, mixing/blending processes free from internally distributed industrial lubricants, equipment bonding/grounding, explosion relief venting for rooms and building components, explosion protection on processing equipment, the appropriate location of dust collection systems, etc.

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