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

OSH Act of 1970 Section (5)(a)(1): 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 dust explosion, deflagration, or other fire hazards while working inside a building with indoor, unprotected dry-type dust collectors. The indoor dry-type dust collectors collected combustible mixture contained metallic particulates ranging from 55 to 75% mass from Kuhlmeyer horizontal twin belt grinding and polishing machines used to dry grind and dry polish stainless-steel. On or about March 23, 2023, employees operating manual, semi-automated and automated Kuhlmeyer horizontal twin belt grinding and polishing machines used to grind and polish stainless steel 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 the Kuhlmeyer horizontal twin belt grinding and polishing machines. a. The indoor dry-type dust collector #1, Donaldson-Torit dust collector Model DFT2-8 s/n 1G761454-001 collected dust from the upstream South Side Kuhlmeyer semi-automatic twin belt grinders and polishers #15 and #2. The indoor dust collector lacked means of explosion protection and deflagration propagation (isolation), exposing employees operating Kuhlmeyer #15 and #2 twin belt grinders and polishers 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 deflagration. In addition, the indoor dust collector returned exhausted air back into the South Side area exposing employees in the South Side area to the hazardous byproducts of a fire (smoke, toxic gases, etc.) in the event of an internal fire. b. Indoor dry-type dust collector #2, Donaldson-Torit Model: DFT2-8 s/n: 1841453-1, collected dust from the south side Kuhlmeyer semi-automated horizontal twin belt grinders and polishers #3 and #4. The indoor dust collector lacked means of explosion protection and deflagration propagation (isolation), exposing employees operating Kuhlmeyer #3 and #4 twin belt grinders and polishers 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 deflagration. In addition, the indoor dust collector returned exhausted air back into the South Side area exposing employees in the South Side area to the hazardous byproducts of a fire (smoke, toxic gases, etc.) in the event of an internal fire. c. Indoor dry-type dust collector #3, Donaldson-Torit Model: DFT2-8 s/n: 2059211-1, collected dust from south side Kuhlmeyer manual horizontal twin belt grinders and polishers #11 and #12. The indoor dust collector lacked means of explosion protection and deflagration propagation (isolation), exposing employees operating Kuhlmeyer #11 and #12 twin belt grinders and polishers 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 deflagration. In addition, the indoor dust collector returned exhausted air back into the South Side area exposing employees in the South Side area to the hazardous byproducts of a fire (smoke, toxic gases, etc.) in the event of an internal fire. d. Indoor dry-type dust collector #9, Donaldson-Torit Model: DFT2-8 s/n: 2143407-1, collected dust from south side Kuhlmeyer manual horizontal twin belt grinders and polishers #9 and #10. The indoor dust collector lacked means of explosion protection and deflagration propagation (isolation), exposing employees operating Kuhlmeyer #9 and #10 twin belt grinders and polishers 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 deflagration. In addition, the indoor dust collector returned exhausted air back into the South Side area exposing employees in the South Side area to the hazardous byproducts of a fire (smoke, toxic gases, etc.) in the event of an internal fire. e. Indoor dry-type dust collector #10, Donaldson-Torit Model: DFT2-8 s/n: 10000802-1, collected dust from south side Kuhlmeyer manual horizontal twin belt grinders and polishers #7 and #8. The indoor dust collector lacked means of explosion protection and deflagration propagation (isolation), exposing employees operating Kuhlmeyer #7 and #8 twin belt grinders and polishers 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 deflagration. In addition, the indoor dust collector returned exhausted air back into the South Side area exposing employees in the South Side area to the hazardous byproducts of a fire (smoke, toxic gases, etc.) in the event of an internal fire. f. Indoor dry-type dust collector #16, Donaldson-Torit Model: DFE2-8 s/n: 15749572-L1-1, collected dust from south side Kuhlmeyer manual horizontal twin belt grinders and polishers #13 and #14. The indoor dust collector lacked means of explosion protection and deflagration propagation (isolation), exposing employees operating Kuhlmeyer #13 and #14 twin belt grinders and polishers 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 deflagration. In addition, the indoor dust collector returned exhausted air back into the South Side area exposing employees in the South Side area to the hazardous byproducts of a fire (smoke, toxic gases, etc.) in the event of an internal fire. g. Indoor dry-type dust collector Mega, Donaldson-Torit Model DFO4-64 s/n: 10343329-L1, collected dust from north side Kuhlmeyer manual horizontal twin belt grinders and polishers K1, K2, K3, K4, K5, K6 and north side Kuhlmeyer automated horizontal twin belt grinders and polishers #1 and #2. The indoor dust collector lacked means of explosion protection and deflagration propagation (isolation), exposing employees operating Kuhlmeyer manual K1, K2, K3, K4, K5, K6 twin belt grinders and polishers and Kuhlmeyer automated horizontal twin belt grinders and polishers #1 and #2 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 deflagration. In addition, the indoor dust collector returned exhausted air back into the South Side area exposing employees in the South Side area to the hazardous byproducts of a fire (smoke, toxic gases, etc.) in the event of an internal fire. Among other methods, one feasible method to correct the hazards would be to follow the guidance in the National Fire Protection Association's (NFPA) Standard 484 "Standard for Combustible Metals, 2022 ed." Section 13.2.3.6.7 (Wet-type dust collection system for operations that generate sparks, hot material, or similar ignition sources), 13.2.4.5 (Wet-type dust collection system requirements), 13.2.4.4 (Dry-type dust collector requirements), 13.2.4.4.11.2 (Explosion protection), 13.2.4.4.11.4 (Isolation protection), 13.2.4.4.13.1 (Recycling of exhaust air), and 7.2 (Dust hazard analysis, DHA). Wisconsin State Fire Code "Chapter SPS 314: Fire Prevention" adopts the 2012 edition of NFPA 1 "Fire Code". Chapter 40 of NFPA 1 (2012) requires adherence with NFPA 484 (2012). Complete a thorough Dust Hazards Analysis (DHA) in accordance with NFPA 484 (2022) and NFPA 652 (2019) to determine the best specific method of abatement for this application based on the properties of the materials. Specific methods of abatement include either utilizing wet-type dust collectors in accordance with the requirements of NFPA 484 (2022) - Section 13.2.4.5 or providing dry-type dust collections systems with protective measures as required by NFPA 484 (2022) - Section 13.2.4.4. Dry-type dust collection system protective measures include: (1) means of explosion protection (deflagration venting to a safe, outdoor location in accordance with NFPA 68 or a deflagration detection and chemical suppression system in accordance with NFPA 69; (2) means of deflagration propagation protection (isolation) in accordance with NFPA 69 through the use of deflagration detection and chemical suppression systems (active isolation) or a combination of flow-actuated flap valves and rotary choke valves (passive isolation); and (3) means of preventing the return of filtered air back into the building without numerous protective measures.