- Hazardous industrial accidents can occur due to leaks, spills, fires, and explosions involving chemicals during transport, storage, manufacture, and use.
- The CSB investigation reports are eye-opening and make people aware of industry-specific and general challenges.
- A common cause is the lack of proper risk assessment and management, which should go beyond regulatory guidelines.
Hazardous chemical disasters occur on a nearly daily basis in the U.S. Between Jan 2021 and October 2023, over 825 incidents were reported across the country, including fatalities, hospitalizations, and community evacuations. Some industries like petroleum, coal, and chemical manufacturing facilities are at higher risk of hazardous accidents. According to the EPA, the number of chemical accidents in the U.S. has increased, and they have also cost up to $477 million. While accidents can occur during railroad transport, most hazardous accidents occur in manufacturing facilities, so employers and safety managers could do more to ensure their workers and the local communities’ health and safety.
This article revisits three recent chemical accident investigations by the U.S. Chemical Safety Board (CSB) and their recommendations to prevent future accidents.
1. Aghorn
On October 26, 2019, hydrogen sulfide (H2S) release at Aghorn’s Foster D waterflood station in Odessa, Texas, caused the death of an employee and a member of the public.
The employee entered the pump house responding to a pump oil level alarm. He tried to isolate the pump by closing the discharge valve and partially shutting the suction valve. However, he had not isolated the pump from energy sources, and during the night, the pump was automatically turned on, and water containing H2S was released due to a broken plunger in the pump. CSB could not ascertain if the pump failure occurred before or after the employee’s arrival at the facility. Exposure to H2S, a toxic gas, proved fatal for the employee. His wife, who reached the pump house searching for the employee, was also exposed to the gas and died.
Probable Cause
The CSB concluded that the probable causes of the accident were based on several failures by Aghorn:
- Failure to ensure operators used personal hydrogen sulfide detectors in or close to equipment and facilities where H2S release was possible.
- There was no development or training to enforce Lockout / Tagout procedures, which led to the operator working on the pump while it was still connected to the energy source.
- Adequate ventilation mechanisms were absent in the physical design of the facility.
- Another likely reason was the failure to maintain site H2S detection and alarm system.
- Poor site security enabled the operator’s spouse to enter the facility.
Recommendation of Remedial Measures
The CSB recommendations to the company for all waterflood stations were as follows:
- Use personal detectors: Aghorn should enforce the use of personal H2S detection devices and personal protection equipment (PPE) when working in areas with potential exposure to over 10 ppm of H2S.
- Training: Meet the requirements under 29 CFR 1910.147 for energy control procedures, training, and inspections
- Engineering controls: Analysis of facility design for ventilation and other mitigation measures at workplaces where workers are exposed to H2S at or over 10 ppm concentrations.
- Safety program: Conduct risk identification, assessment, and monitoring, focusing on employees and non-employees. Based on the study, ensure proper design, facility maintenance, and training related to H2S. Have a written site-specific security program.
- Monitor H2S in the facility: The employers must install, calibrate, and maintain H2S detectors with multiple layers of alerts that uniquely identify H2S risk in places where the gas levels could rise above permitted levels of 10 ppm. The alerts must include audio and visual alarms to alert workers and the local community of significant H2S releases. The workers must be trained through routine operations in using and maintaining these gas detectors.
For more information on the CSB investigation of the accident, read their report published in May 2021.
2. Bio-Lab Lake Charles Chemical Fire and Release
Category 4 Hurricane Laura damaged buildings at the Bio-Lab, Inc. Lake Charles (Bio-Lab) facility, Westlake, Louisiana, that stored the chemical trichloroisocyanuric acid (TCCA). The facility produced TCCA-based formulations for water sanitizers for swimming pools and hot tubes by killing bacteria and algae.
Anticipating the hurricane, most of the product was removed from the facility before landfall. However, a million pounds remained in the facility due to the non-availability of transport. The management and workers placed sandbags to prevent floodwater entry on August 25, 2020. The management evacuated the facility due to the hurricane’s strength the following morning, the 26th.
The hurricane landed on August 27, 2020, and the rainwater entering the facility caused TCCA decomposition, producing hazardous gas chlorine and heat that destroyed the production building and other structures. No one was injured, but the facility was damaged. Also, the nearby Interstate was shut down for 28 hours, and a shelter-in-place order was placed for the local community.
After the incident, Bio-Lab had to spend around $250 million in redesigning and reconstructing its damaged facility.
Figure 1: “Photo of the plume with toxic chlorine from decomposition in Bio-Lab Plant 4 approaching the Calcasieu River Bridge near the facility. (Credit: CBS 4WWL [23]).” (Image credits: CSB)
Probable Cause
The CSB identified the following causes of the chemical accident at Bio-Lab Plant 4:
- Chlorine gas was formed due to the reaction of trichloroisocyanuric acid-based formulation with rainwater. The reaction heat also started a fire in the facility.
- The facility buildings did not meet the existing wind design requirements.
- The facility was also unprepared for extreme weather, as it had not followed industry guidelines.
- The fire protection system at the facility was inadequate and nonfunctional.
- Occupational Safety and Health Administration (OSHA) and U.S. Environmental Protection Agency (EPA) regulations do not cover hazardous chemicals produced from combinations of chemicals and processes. The facility did not cover this aspect in its safety program as it was not legally liable.
Recommendations
The CSB recommended that OSHA and EPA cover catastrophic reactive hazards and provide information, test data, and chemical abstract services. In addition, its recommendations for employers were as follows:
- Extreme weather preparedness: Bio-Lab should evaluate risks from hurricanes, storms, rainwater, and wind to their facilities and implement safeguards. The measures must include constructing or strengthening buildings with hazardous materials that can withstand storms. Safeguard against processes that could produce hazardous chemicals in storms.
- Process Hazard Analysis (PHA): The employers should develop and implement PHA management systems in all buildings that process or store TCCA. These systems must be revalidated every five years. It would address the reaction of TCCA with water to form chlorine.
- Revise emergency response plans: Bio-Lab Lake Charles’s emergency plans should be revised to incorporate better fire protection and train the employees to use emergency equipment one month before each hurricane season.
In addition to these measures, we suggest that the facility install chlorine detectors where TCCA is stored or processed to identify instances when the gas levels rise above prescribed limits. For more information on the Bio-Lab Lake Charles incident, read the CSB 2023 investigation report.
3. Wacker Polysilicon Chemical Release
During maintenance activities, Wacker Polysilicon suffered an equipment fracture in a graphite heat exchanger that released hydrochloride (HCl) on November 13, 2020, in its Charleston, Tennessee, facility. Seven workers from two contracting firms were on the platform during the incident. A team of three with full-body chemical-resistant suits applied disproportionate torque to flange bolts, cracking the pipe and releasing HCl. Another team of four had only flame-resistant clothing and was working on pipe insulation.
The white fumes of HCL reduced visibility and prevented the people from finding and reaching the stairs. The workers without HCL-resistant suits fell to the ground while climbing pipes to escape the fumes. One of them was fatally injured, and two others had serious injuries.
Probable cause
The CSB investigations into the chemical accident revealed the following causes:
- Wacker lacked a written procedure leading to the event. Wacker did not have written instructions for multiple bolts with different torque requirements. The work was assigned to piping manufacturers who also didn’t have varying torque requirements.
- Wacker also lacked control of hazardous energy. It didn’t consider torquing operations as activities requiring isolating hazardous energy because they had neither done a risk assessment nor had mitigating measures to prevent HCL release.
- Wacker lacked a SIMOPS program that could have prevented two unrelated teams from working simultaneously. Also, workers unrelated to torquing were not appropriately dressed or ready for HCl exposure. There is also no regulation on SIMSOPs.
- The absence of regulatory guidance on exit means from open-air structures contributed to Wacker’s lack of exit from the equipment.
Recommendations
CSB investigations considered the Wacker incident preventable and revealed lacunae in regulations and employer action.
CSB recommended that OSHA initiate or modify existing standards so that employers identify dangerous combinations of SIMOPs and implement safeguards, which also covered contractors’ activities. For the employer, CSB had the following recommendations:
- Procedures: Develop detailed written maintenance procedures for torquing activities, mentioning specifications for different bolts for equipment with hazardous materials. Ensure that procedures and risk management plans follow 29 CFR 1910.119 standards.
- Develop SIMOPs program: Wacker must identify potential SIMPOs, especially hazardous interactions, and formulate necessary safeguards, including emergency response services and personnel. Ensure coordination and information sharing between SIMOPs.
- Add egress: Install additional exit means for multi-floor equipment and desorption tower platforms. Inform and drill workers about the exits’ use.
Preparedness
Many industrial chemical accidents can be prevented by following regulations and proper risk management of issues, even if rules do not cover them. These can be done by avoiding process-specific conditions, as in the Bio-Lab incident. Risk management and mitigation should not be conducted only for compliance but to ensure workers’ and facility safety in a comprehensive industrial hygiene and safety program. Ensuring multiple gas detection levels with fixed and portable gas analyzers is a risk-mitigating action that can go a long way in keeping people and facilities safe, as shown in the Aghorn incident.
It is also necessary for employers to stay informed of new regulations that evolve to address challenges that can be industry-specific or posed by extreme weather.
Contact Interscan to learn about our fixed and portable gas detectors for over 20 hazardous gases.
Sources
Coming Clean and the Environmental Justice Health Alliance for Chemical Policy Reform (2023, November 9). Key Findings: Chemical Incident Tracking 2021-2023. Retrieved from https://comingcleaninc.org/assets/media/images/Chemical%20Disaster%20Prevention/Key%20Findings%202021-2023%20FINAL.pdf
CSB.Gov (n.d.). Completed Investigations. Retrieved from https://www.csb.gov/investigations/completed-investigations/?Type=2&pg=2
Gillam, c. ( 2023. Feb 25). A near-daily disaster; hazardous chemical accidents common across the US. Retrieved from https://www.thenewlede.org/2023/02/a-near-daily-disaster-hazardous-chemical-accidents-common-across-us/
