- Heating Equipment
In addition to the probable causes listed above, the lack of a standard operating procedure for hydrogen leak detection was one of the probable causes of this incident. Additional contributing factors included the following:
- Severe pipe corrosion due to the presence of hot water in the pipe trench
- Hydrogen piping located in a concealed space
- Limitations of the flash-fire-resistant garments worn by plant employees.
Key findings noted in the CSB report included:
Significant accumulations of combustible iron powder fueled fatal flash fires when lofted near an ignition source.
Facility management were aware of the combustibility hazard two years earlier but did not mitigate the hazard with engineering controls or housekeeping.
The plant did not institute combustible gas monitoring or employee training to help avoid flammable gas fires and explosions.
OSHA did not include iron and steel mills in its Combustible Dust National Emphasis Program.
The 2006 International Fire Code (IFC) does not require enforcement of the more comprehensive and rigorous NFPA standards for the prevention of dust fires and explosions.
The state and city did not enforce recommended IFC practices.
The local fire department inspected the facility just months before the fatal hydrogen explosion and dust flash fire but did not cite or address the combustible dust hazards that were present.
The flame-resistant clothing provided to the plant employees did not adequately protect them from the hydrogen explosion and dust flash fires.
There was no corporate oversight regarding the management of combustible dusts even though there had been a succession of serious accidents at the facility in the past.
The CSB made recommendations regarding combustible dust hazards to OSHA, the International Code Council, the state, the company, the Metal Powder Producers Association, the city, and the local fire department. Recommendations to the company covered both combustible dust and flammable gases as shown below.
Conduct periodic inspection audits of the facility for compliance with the relevant NFPA standards (484, 499, 497, 2, and 2113), using knowledgeable experts, and implement all recommended corrective actions.
Develop a training program for combustible dust hazards for all employees and contractors.
Implement a preventive maintenance program and leak detection/mitigation procedures for all flammable gas piping and gas processing equipment.
Implement a near-miss reporting and investigation policy.