Text For Citation: 01 Item/Group: 001 Hazard:

Section 5(a)(1) of the Occupational Safety and Health Act of 1970: The employer did not furnish employment and a place of employment which were free from recognized hazards that were causing or were likely to cause death or serious physical harm to employees in that employees were exposed to combustible food ingredient dust explosion and deflagration hazards while working inside a building with indoor, dry-type dust collectors collecting combustible dusts, containing whey powder, non-dairy powder, and dairy powder. On or about December 13, 2023, employees dumping dry ingredients, packaging dry ingredients were exposed to combustible dust explosion, deflagration, and fire hazards associated with the indoor dry-type Donaldson-Torit dust collectors. The indoor dry-type dust collectors were used to collect combustible dust from receivers, mixers, and packaging machines. a. The indoor dry-type dust collector, Donaldson Torit Model DLMC s/n 14277477, was used to collect combustible dust from two mixers, a manual dump station, a bulk dump station, and a packaging line on the Automated Line (new line). The indoor dust collector had means of explosion protection in the form of explosion venting directed outside but lacked means of deflagration propagation (isolation), exposing employees dumping dry ingredients and packaging dry ingredients to deflagration propagation hazards (exiting flame front through equipment openings/connections) in the event of an internal dust collector deflagration. b. The indoor dry-type dust collector, Donaldson Torit Model DLMC s/n 11275904 L1, was used to collect combustible dust from two mixers and packaging line on the Manual Line (old line). The indoor dust collector lacked means of explosion protection and deflagration propagation (isolation), exposing employees dumping combustible dry ingredients and packaging combustible dry ingredients to explosion hazards (exiting pressure wave, flame front, vessel fragmentation from vessel overpressure) and deflagration propagation hazards (exiting flame front through equipment openings/connections) in the event of an internal dust collector deflagration. Among other methods, a feasible method to correct the hazards would be to follow the guidance in the National Fire Protection Association's (NFPA) Standard 61 "Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities, 2020 ed." - Sections 9.3.4.2.1 (Permitted Indoor Dust Collector Practices, Protection), 9.7.3.1 (Equipment Protection Requirements), 9.7.4 (Equipment Isolation), 9.3.1 (Risk Assessment in Equipment Design), and Chapter 7 (Dust Hazard Analysis, DHA). Specifically - Instance A, Automated Line (new line) dust collector: (1) Provide a means of deflagration propagation protection (isolation) to protect against deflagration propagation to upstream equipment and work areas via the dirty air inlet ducting in accordance with NFPA 69 "Standard on Explosion Prevention Systems". An example of a feasible passive isolation device for this location that works in accordance with a dust collector protected by explosion venting is a flow-actuated flap valve. (2) Provide a means of deflagration propagation (isolation) to protect against deflagration propagation to the room through the unit's material discharge hopper opening in accordance with NFPA 69. An example of a feasible passive isolation device for this location is a rotary valve designed with criteria to provide flame quenching through close-clearance vanes. Instance B, Manual Line (old line) dust collector: (1) Provide a means of explosion protection in accordance with NFPA 68 "Standard on Explosion Protection by Deflagration Venting." An example of a feasible means of explosion protection that may work in this area is explosion venting to an outdoor restricted, safe area. (2) Provide a means of deflagration propagation protection (isolation) to protect against deflagration propagation to upstream equipment and work areas via the dirty air inlet ducting in accordance with NFPA 69. An example of a feasible passive isolation device that works in accordance with a dust collector protected by explosion venting is a flow-actuated flap valve. (3) Provide a means of deflagration propagation (isolation) to protect against deflagration propagation to the room through the unit's material discharge hopper opening in accordance with NFPA 69. An example of a feasible passive isolation device for this location is a rotary valve designed with criteria to provide flame quenching through close-clearance vanes.