Contributory Factors: Organized Procedures

At approximately 2:00 pm on December 11, 2002, a maintenance employee entered the wastewater treatment (WWT) room at Environmental Enterprises, Inc. (EEI), in Cincinnati, Ohio, to retrieve a tool. His path brought him directly alongside the WWT clarifier, an open-top tank with a conical bottom for settling solids (Figure 1).

As the mechanic approached the clarifier, he noticed a “rotten egg” odor that became stronger as he moved forward. He suddenly felt pressure in his lungs and was unable to breathe. He attempted to flee the area but was overcome by hydrogen sulfide (H2S) gas and collapsed.

Fortunately, fellow employees found the victim a few moments later and pulled him to safety. He recovered, and there were no other injuries. .

KEY ISSUES:
• HAZARD COMMUNICATION
• OPERATING PROCEDURES
• MANAGEMENT OVERSIGHT
• MECHANICAL INTEGRITY

ROOT CAUSES:
1. The facility had no written procedures for operating the WWT area.
2. The operator responsible for the WWT area had no formal training in waste treatment or chemistry.
3. This incident may have been avoided if the operator had been aware of the possible reactions that can produce H2S gas.
4. EEI did not have a formal system for investigating incidents and communicating findings to employees.
5. The facility did not implement procedures or assign responsibilities for calibrating, inspecting, and maintaining the H2S detector.
6. Management oversight could have ensured that then proper treatment methods were used.

Image Credit: CSB

An explosion severely injured a graduate student at Texas Tech University in Lubbock, Texas, in the chemistry department during the handling of a high-energy metal compound, which suddenly detonated. Texas Tech had entered into an agreement with Northeastern University, which holds a contract from the U.S. Department of Homeland Security to study the high-energy materials.

KEY ISSUES:
• LABORATORY SAFETY MANAGEMENT FOR PHYSICAL HAZARDS
• HAZARD EVALUATION OF EXPERIMENTAL WORK IN RESEARCH LABORATORIES
• ORGANIZATIONAL ACCOUNTABILITY & OVERSIGHT OF SAFETY

Image & AcciMap Credit: CSB

On January 16, 2002, highly toxic hydrogen sulfide gas leaked from a sewer manway at the Georgia-Pacific Naheola mill in Pennington, Alabama. Several people working near the manway were exposed to the gas. Two contractors from Burkes Construction, Inc., were killed. Eight people were injured–seven employees of Burkes Construction and one employee of Davison Transport, Inc. Choctaw County paramedics who transported the victims to hospitals reported symptoms of hydrogen sulfide exposure.

KEY ISSUES:
• REACTIVE HAZARD IDENTIFICATION
• HYDROGEN SULFIDE SAFETY
• EMERGENCY RESPONSE

ROOT CAUSES:
1. Good engineering and process safety practices were not followed when joining the drain from the truck unloading station and the oil pit to the acid sewer.
2. There was no management system to incorporate hazard warnings about mixing sodium hydrosulfide (NaSH) with acid into process safety information.

Image Credit: CSB

An explosion occurred at one of Petrobras’ refineries. The blast occurred at a hydrogen conduit in an enclosed space, causing a flare and a displacement of air that threw the contract workers against the refinery’s metal structure.

Proximate causes:
• Inadequate maintenance
• Failure following procedures
• Lack of work rules/policies/ standards/procedures
• Physical condition (the accident may have been the result of maintenance work being carried out under tight deadlines and long shifts imposed on refinery workers)
• Mental stress
• Mental state

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)
Image Credit: Daily Motion

A gas leak followed by explosion occurred during an inspection process due to the loose of valve bolt.

Proximate causes:
• Inadequate training/knowledge transfer (Lack of understanding the process);
• Lack of work rules/policies/ standards/procedures (wrong procedures for inspections);
• Inadequate work rules plan (lack of the pre-start safety review before inspection).

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)
Image Credit: Wikipedia

An explosion occurred when 8 personnel were working on the repair of a catalyst tower.

Proximate causes:
• Inadequate training/knowledge transfer (Lack of understanding the process)
• Lack of work rules/policies/ standards/procedures (wrong procedures for inspections);
• Inadequate work rules plan (lack of the pre-start safety review before inspection).

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)

Explosion in an oil and gas production ship rented by Petrobras. The explosion occurred aboard the FPSO unit. A leak of flammable substance in the pump room was the cause of the explosion.

Proximate causes:
• Failure in following procedures
• Lack of work rules/policies/ standards/procedures (breach of operational procedures for the pumping of fluids)
• Inadequate engineering/design
• Inadequate management/ supervision (installation of equipment in pipe without proper technical specification and registration of the change)
• Work exposure to hazardous chemicals (flammable substances) Inadequate assessment of needs and risks

Marsh (https://www.marsh.com/us/insights/research/100-largest-losses-in-the-hydrocarbon-industry.html):

An explosion on a FPSO off the coast of Brazil resulted in nine fatalities and multiple wounded. The accident happened as the vessel was anchored in the Atlantic Ocean 120 kilometres from the coast of Espirito Santos, Brazil. The FPSO is a converted very large crude oil tanker (VLCC), designed to produce up to 10 million cubic meters of natural gas. It is understood that a condensate leak during a fluid transfer operation released a cloud of flammable vapor into the engine room, resulting in an explosion in the machinery space. The majority of fatalities were believed to be part of the emergency response team. FPSO took on water, but the explosion did not result in a breach of the hull of the vessel.

[ Property Damage $250 Million. Estimated Current Value $264 Million ]

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)
Image Credit: AFP / Getty Images

A rail car with more than 100 tanks of crude bakken oil derailed in West Virginia, generating a huge fireball, the evacuation of hundreds of people and, a spill into the Kanawha River.

Hundreds evacuated – FRE issued CSX and Sperry Rail Service $25.000 fines each

Proximate causes:
• Inadequate tools, equipment & vehicles (rail defect)

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)
Image Credit: US Coast Guard

An explosion occurred due to an overflow of a slurry mixing tank, containing potassium sulfide, potassium dihydrogen phosphate, and MAP.

Proximate causes:
• Inadequate training/knowledge transfer (Lack of understanding the process);
• Lack of work rules/policies/ standards/procedures (wrong procedures for inspections);
• Inadequate work rules plan (lack of the pre-start safety review before inspection).

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)

A high-pressure steam (3.7 MPa) discharge occurred during a maintenance process, resulting in three field workers burned to death.

Proximate causes:
• Lack of work rules/policies/ standards/procedures (wrong procedures for inspections);
• Inadequate work rules plan (lack of the pre-start safety review before inspection).

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)

Four reactors exploded after an initial fire in a warehouse in the plant. The toxic gas released due to the fire and explosion affected the local community. Electrical short circuit and improper shutdown was the reason that triggered the incident.

Proximate causes:
• Inadequate tools, equipment & vehicles (Electrical appliances shortcut)
• Failure in following procedure (improper shutdown)

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)

An explosion occurred when 6 personnel were working on the repair of a catalyst tower

Proximate causes:
• Lack of work rules/policies/ standards/procedures (wrong procedures for inspections);
• Inadequate work rules plan (lack of the pre-start safety review before inspection).

Source: A web-based collection and analysis of process safety incidents (https://www.sciencedirect.com/science/article/abs/pii/S0950423016302285)

At approximately 1:20 p.m. on March 23, 2005, a series of explosions occurred at the BP Texas City refinery during the restarting of a hydrocarbon isomerization unit. Fifteen workers were killed and 180 others were injured. Many of the victims were in or around work trailers located near an atmospheric vent stack. The explosions occurred when a distillation tower flooded with hydrocarbons and was overpressurized, causing a geyser-like release from the vent stack.

KEY ISSUES:
• SAFETY CULTURE
• REGULATORY OVERSIGHT
• PROCESS SAFETY METRICS
• HUMAN FACTORS

ROOT CAUSES:
1. BP Group Board did not provide effective oversight of the company’s safety culture and major accident prevention programs.

2. Senior executives:
• inadequately addressed controlling major hazard risk. Personal safety was measured, rewarded, and the primary focus, but the same emphasis was not put on improving process safety performance;
• did not provide effective safety culture leadership and oversight to prevent catastrophic accidents;
• ineffectively ensured that the safety implications of major organizational, personnel, and policy changes were evaluated;
• did not provide adequate resources to prevent major accidents; budget cuts impaired process safety performance at the Texas City refinery.

3. BP Texas City Managers did not:
• create an effective reporting and learning culture; reporting bad news was not encouraged. Incidents were often ineffectively investigated and appropriate corrective actions not taken.
• ensure that supervisors and management modeled and enforced use of up-to-date plant policies and procedures.
• incorporate good practice design in the operation of the ISOM unit.
• ensure that operators were supervised and supported by experienced, technically trained personnel during unit startup, an especially hazardous phase of operation; or that
• effectively incorporated human factor considerations in its training, staffing, and work schedule for operations personnel.

Image Credit: CSB

On March 27, 1998, at approximately 12:15 pm, two workers at Union Carbide Corporation’s Taft/Star Manufacturing Plant (the plant) in Hahnville, Louisiana, were overcome by nitrogen gas while performing a black light inspection at an open end of a 48-inch-wide horizontal pipe. The 48-inch pipe was open because chemical-processing equipment had been shut down and opened for major maintenance. Nitrogen was being injected into the process equipment primarily to protect new catalyst in reactors from exposure to moisture. The nitrogen was also flowing through some of the piping systems connected to the reactors. The nitrogen was venting from one side of the open pipe where it had formerly been connected to an oxygen feed mixer. No warning sign was posted on the pipe opening identifying it as a confined space or warning that the pipe contained potentially hazardous nitrogen.

The two workers had placed a sheet of black plastic over the end of the pipe to provide shade to make it easier to conduct the black light test during daylight. While working just outside the pipe opening and inside of the black plastic sheet, the two workers were overcome by nitrogen. One worker died from asphyxiation. The other worker survived but was severely injured.

KEY ISSUES:
• USE OF NITROGEN IN CONFINED SPACES
• SAFETY OF TEMPORARY ENCLOSURES

ROOT CAUSES:
1. Procedures to control potential hazards created by erecting temporary enclosures around nitrogen-containing equipment were inadequate.
2. Nitrogen and confined space hazard warnings were inadequate.

Image Credit: CSB