Didion Milling Company Explosion and Fire

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Accident Description

Accident: Didion Milling Company Explosion and Fire

Location: Location: Cambria, WI

Accident Occurred On: 05/31/2017 | Final Report Released On: 12/06/2023

Accident Type: Explosion and Fire

Investigation Status: The CSB's final report was released on December 6, 2023.

On May 31, 2017, combustible dust explosions at the Didion Milling facility in Cambria, Wisconsin, killed five of the 19 employees working on the night of the incident. The other 14 were injured.

Final Reports

FINAL REPORT: Fatal Combustible Dust Explosions at Didion Milling Inc.

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Recommendations

Didion Milling, Inc.

2017-07-I-WI-1

Contract a competent third party to develop a comprehensive combustible dust process safety management system, such as OSHA’s Process Safety Management standard or the requirements in the 2019 edition of NFPA 652, Standard on the Fundamentals of Combustible Dust, Chapter 8, which includes, at a minimum, the following elements:

a. Management of Change for combustible dust;

b. Process Safety Information Management;

c. Management of Audits and Inspections;

d. Fugitive Dust Management;

e. Incident Investigation;

f. Dust Hazard Analyses;

g. Management of Engineering Controls for combustible dust

h. Personal Protective Equipment; and

i. Emergency Preparedness.

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary

2017-07-I-WI-2

Contract a competent third party to develop and implement modifications to the pneumatic conveying and dust collector ductwork systems in accordance with guidance such as NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities, 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, to include, at a minimum:

a. Ensure minimum required transport velocity is maintained throughout the system.

b. Implement a periodic inspection and testing program for pneumatic conveying and dust collector ductwork systems, following industry guidance such as NFPA 91, Standard for Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Particulate Solids, and FM Global guidance. The program should include cleaning on a set frequency and measuring transport velocities on a routine basis to ensure proper system function.

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary

2017-07-I-WI-3

Contract a competent third party to perform dust hazard analyses (DHAs) on all buildings and units that process combustible dust. Ensure that the DHAs are revalidated at least every five years. Implement pre-deflagration detection, deflagration venting, deflagration suppression, deflagration isolation, and deflagration pressure containment engineering controls identified in the initial and revalidation DHA in accordance with NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities, NFPA 68, Standard on Explosion Protection by Deflagration Venting, NFPA 69, Standard on Explosion Prevention Systems, and NFPA 652, Standard on the Fundamentals of Combustible Dust.

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary

2017-07-I-WI-4

Contract a competent third party to assess and implement engineering controls for the structural design and venting requirements of the reconstructed facility to ensure they meet the requirements and guidance in NFPA 68, Standard on Explosion Protection by Deflagration Venting, for adequacy of venting capacity.

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary

2017-07-I-WI-5

Incorporate recording any paper-based process safety information into Didion’s existing electronic records management system so that the information can be reliably retained, retrieved, and analyzed in the event of a catastrophic incident.

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary

2017-07-I-WI-6

Contract a competent third party to perform personal protective equipment hazard analyses, such as those prescribed by NFPA 2113, Standard on Selection, Care, Use, and Maintenance of Flame-Resistant Garments for Protection of Industrial Personnel Against Short-Duration Thermal Exposures from Fire, and require appropriate flame-resistant garments for all operations that handle combustible dusts during normal and upset conditions.

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary

2017-07-I-WI-7

Contract a competent third party to update the facility emergency response plan and train all employees on updated emergency response plan. The update should include the guidance in NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities, and NFPA 652, Standard on the Fundamentals of Combustible Dust, Chapter 8 and Section A.8.10.1, which includes, at a minimum, the following elements:

a. A signal or alarm system;

b. Emergency shutdown procedures;

c. Provide instructions for when and how to trigger emergency evacuations;

d. Provide instructions for when to notify emergency responders for need of assistance;

e. Response to potential fire scenarios, such as smoldering fires inside equipment; and

f. Prevent firefighting of process fires inside equipment.

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary

2017-07-I-WI-8

Contract a competent third party to assess and update the pre-deflagration detection and suppression engineering controls, such as those discussed in Chapter 9 of the 2019 edition of NFPA 69, Standard on Explosion Prevention Systems, for adequacy to detect and alarm employees of an emergency situation, such as a smoldering fire, and trigger an evacuation.

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary

2017-07-I-WI-9

Contract a competent third party to develop and implement a process safety leadership and culture program, based on the guidance of the CCPS’s Guidelines for Auditing Process Safety Management Systems and Process Safety: Leadership from the Boardroom to the Frontline. The program should include, at a minimum, the following elements:

a. A process safety policy;

b. A process safety leadership and culture committee;

c. Appropriate goals for process safety;

d. A commitment to process safety culture;

e. Leading and lagging process safety metrics;

f. Process Safety Culture Assessments; and,

g. Engagement with external process safety leadership and culture experts.

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary
National Fire Protection Association (NFPA)

2017-07-I-WI-13

Update NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities, or a successor standard, to incorporate, at a minimum, the following elements:

1. Unify the requirements for performing dust hazard analyses to remove equipment exemptions and require the assessment of all processes, such as cyclones, as required in:

a. The 2019 edition of NFPA 652, Standard on the Fundamentals of Combustible Dust

b. Chapters 3, 5, and 6 of the CCPS’s Guidelines for Combustible Dust Hazard Analysis.

2. Incorporate the additional guidance for Management of Change to include but not limited to:

a. Harmonize the 2019 edition of NFPA 652, Standard on the Fundamentals of Combustible Dust, requirements for section 8.12.2.4, modifications to operating and maintenance procedures, and section 8.12.2.4, employee training requirements.

b. Chapter 3 and Appendix B of the CCPS’s Guidelines for the Management of Change for Process Safety, such as addressing temporary changes, operating and maintenance procedures, employee training, and dust testing results, to standardize MOC requirements across all industries that handle combustible dust.

3. Update the requirements for incident investigation management systems, to include but not limited to:

a. Incorporate the optional guidance of the 2019 edition of NFPA 652, Standard on the Fundamentals of Combustible Dust, as a mandatory requirement.

b. Chapters 4 and 10 of CCPS’s Guidelines for Investigating Process Safety Incidents (3rd Edition).

Status: Open - Acceptable Response or Alternate Response

Open - Acceptable Response or Alternate Response (O - ARAR) - Response from recipient indicates a planned action that would satisfy the objective of the recommendation when implemented.

Recommendation Status Change Summary
Occupational Safety and Health Administration (OSHA)

2017-07-I-WI-10

Promulgate a standard for all industries that handle combustible dust, which should be based on the requirements of current NFPA combustible dust standards, including NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities, NFPA 484, Standard for Combustible Metals, NFPA 652, Standard on the Fundamentals of Combustible Dust, NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids, NFPA 655, Standard for Prevention of Sulfur Fires and Explosions, NFPA 664, Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities, or a successor standard. At a minimum, the standard should include the following elements:

a. Hazard Recognition;

b. Dust Hazard Analysis;

c. Management of Change;

d. Incident Investigation;

e. Engineering Controls;

f. Building Design;

g. Fugitive Dust Management;

h. Operating Procedures;

i. Process Safety Information;

j. External Audit Management;

k. Training;

l. Emergency Response; and

m. Personal Protective Equipment.

(Superseded the following recommendations: 2006-1-H-R1 from the Combustible Dust Hazard investigation, 2008-05-I-GA-R11 from the Imperial Sugar investigation, and 2011-04-I-TN-R1 and 2011-04-I-TN-R2 from the Hoeganaes Corporation investigation)

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary

2017-07-I-WI-11

Following implementation of CSB Recommendation No. 2017-07-I-WI-R10, update the Grain Handling Facilities Standard to clarify grain handling facilities with combustible dust are covered by the new Combustible Dust Standard.

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary

2017-07-I-WI-12

Develop a program to trigger follow-up inspections when hazard alert letters are issued for combustible dust hazards and there is insufficient evidence to demonstrate that those hazards have been abated.

Status: Open - Awaiting Response or Evaluation/Approval of Response

Open - Awaiting Response or Evaluation/Approval of Response (O - ARE/AR) - The recipient has not submitted a substantive response, or the evaluation by CSB staff of a response is pending, or the Board has not yet acted on staff recommendation of status.

Recommendation Status Change Summary