At 6:45 p.m. on October 28, 2021, an employee was circulating a tank of hydrogen sulfide when a burner box, which was 15 feet away, was turned on and the hydrogen sulfide that was in the atmosphere ignited. The employee was hospitalized to treat second and third-degree burns to his hands and face.
Source: OSHA.gov
"On or about January 28, 1993, Employee #1, a contract welder, was repairing and replacing flanges on storage tanks in order to install a closed ventilation system. The storage tanks contained sodium sulfide, which reacts with acid to generate hydrogen sulfide gas. This highly flammable gas accumulated in a vapor space. Prior to the accident, a tank flashed while being cut or welded into by the employee. When a lighted torch was brought in proximity, the tank ruptured. Employee #1 died. Employee #2 had gone up on a tank to tell Employee #1 not to cut into the tank when the tank exploded. Employee #2 was hospitalized."
Source: OSHA.gov
"At 10:30 a.m. on September 30, 2019, an employee was performing maintenance on a storage tank battery for oil and gas operations support. The employee was on a crew which was working on a line which was not pressurizing properly. As the employee was working on the line, the pop off valve relieved causing the employee to be struck by released hydrogen sulfide. The employee fell off the tank, rupturing his kidney and fracturing his left fibula and right hip. The employee was hospitalized".
Source: OSHA.gov
"At 12:30 p.m. on June 7, 2021, an employee entered a sewer manhole to estimate the amount of materials needed to perform a manhole repair when the employee was overcome by high levels of hydrogen sulfide at the base of the manhole shortly after entry. The employee did not perform atmospheric monitoring and had not donned his harness with rescue tripod before entry into the confined space. A four gas monitor and rescue equipment were located in the employee's work vehicle. Coworker #1 (attendant) and Coworker #2 (helper) were not trained or equipped for performing a confined space entry rescue. A volunteer fire department responded within 8 minutes and performed the confined space entry rescue shortly after arrival. The employee was killed by overexposure to hydrogen sulfide"
SOurce: OSHA.gov.
On May 17, 2010 Employee #1, Employee #2, Employee #3 and Employee #4, were in the pipe rack planning to install a flanged spool piece on the Epi three transfer line. The line had been isolated at the west end and the east end. A one inch bleeder valve on both ends was yellow tagged open and returned to operations.
Employee #1, Employee #2, and Employee #3 had pulled their tools and bolts up. Employee #4, the rigger had gone up to the job site to figure out the best way to lift the pipe spool in place. As all this was going on, an employee of the host employer connected an eighty pound nitrogen hose to the one inch bleeder. That worker then charged the line with the eighty pounds of nitrogen.
Shortly after that, ten gallons of epichlorohydrin was released from the west end of the open pipe hitting Employee #1 directly in the chest and midsection. Employee #1 was admitted to the hospital immediately by life flight. Employee #2 was exposed on the neck, back and hands, and admitted to the hospital. Employee #3 had mild splotchy discoloration of several small areas on the hand and arms. Also a sore throat from inhalation. Employee #4 had splotchy superficial burns on the arms and back as well as a mild associated rash.
Source:OSHA.gov
"At 1:00 p.m. on September 27, 1993, a hydrostatic test crew operator and two helpers began testing 19 sections of 7 inch P-110 casing pipe at 9,500 psi.
The hydrostatic crew would roll the pipe onto the holding devices, check the drift (proper dimensions), apply thread dope, install the front header plug and rear "gun" plug, align the header plug bleed valve, fill the pipe with water, close the bleed valve, tighten the header plug, and assume their designated positions for pressure testing in accordance with pressure test specifications.
After conducting the pressure test, employees would drain the water, remove the plugs, roll the pipe down the line, grease the threads, and stencil the pipe.
Near 4:00 p.m. the crew was working on pipe section number 18. About 4:15 p.m., the pipe was filled with water and the crew began the pressure test. At 1,000 psi the header plug exploded blew out of the coupler on the pipe and struck Employee #1. Coworkers rushed to his aid and emergency medical services were notified. CPR was administered. Medical services arrived and transported Employee #1 to the hospital, where he died at about 5:00 p.m".
Source: OSHA.gov
"On February 22, 2020, a carbon dioxide (CO2) pipeline ruptured in proximity to the community of Satartia, Mississippi. The rupture followed heavy rains that resulted in a landslide, creating excessive axial strain on a pipeline weld.
• Carbon dioxide is considered minimally toxic by inhalation and is classified as an asphyxiant,
displacing the oxygen in air. Symptoms of CO2 exposure may include headache and drowsiness.
Individuals exposed to higher concentrations may experience rapid breathing, confusion,
increased cardiac output, elevated blood pressure, and increased arrhythmias. Extreme CO2
concentrations can lead to death by asphyxiation.
• When CO2 in a super-critical phase (which is common for CO2 pipelines) releases into open air, it
naturally vaporizes into a heavier than air gas and dissipates. During the February 22 event,
atmospheric conditions and unique topographical features of the accident site significantly
delayed dissipation of the heavier-than-air vapor cloud. Pipeline operators are required to
establish atmospheric models to prepare for emergencies
• Local emergency responders were not informed of the rupture and the nature of the
unique safety risks of the CO2 pipeline. As a result, responders had to guess the nature of the risk,
in part making assumptions based on reports of a “green gas” and “rotten egg smell” and had to
contemplate appropriate mitigative actions. Fortunately, responders decided to quickly isolate
the affected area by shutting down local highways and evacuating people in proximity to the
release. No fatalities were reported.
• This event demonstrated the need for:
o Pipeline company awareness and mitigation efforts directed at addressing integrity
threats due to changing climate, geohazards, and soil stability issues.
o Improved public engagement efforts to ensure public and emergency responder
awareness of nearby CO2 pipeline and pipeline facilities and what to do if a CO2 release
occurs. This is especially important for communities in low-lying areas, with certain
topographical features such as rivers and valleys".
At approximately 3:30 p.m. on June 14, 2012, Employee #1 was performing hydro testing of two recently constructed and installed crude oil pipelines. The employee removed a pressure test manifold from a pressure test flange while the pipeline contained a pressure of 2000 psi. Employee #1 did not lock-out the pipe valves, nor bleed the pressure off of the line prior to removing the pressure test manifold. The employee was struck-by the pressure test manifold that was propelled by the stored pipeline pressure. Employee #1 was transported by the impact of the manifold for a distance of 40 feet. The steel pressure test manifold impacted the skull of the employee which resulted in injuries to the employee and subsequent death.
Source:OSHA.gov
At approximately 3:30 p.m. on June 14, 2012, Employee #1 was performing hydro testing of two recently constructed and installed crude oil pipelines. The employee removed a pressure test manifold from a pressure test flange while the pipeline contained a pressure of 2000 psi. Employee #1 did not lock-out the pipe valves, nor bleed the pressure off of the line prior to removing the pressure test manifold. The employee was struck-by the pressure test manifold that was propelled by the stored pipeline pressure. Employee #1 was transported by the impact of the manifold for a distance of 40 feet. The steel pressure test manifold impacted the skull of the employee which resulted in injuries to the employee and subsequent death.
Source: OSHA.gov
Note: Obviously the pipeline was not filled up complete;y with water and air was pressurized, resulting in the propelling of the pressure test manifold
On March 6, 2018, a 49-year-old pipefitter was hit in the chest by a pressurized 12-inch diameter polyvinyl chloride (PVC) pipe during a hydrostatic pressure test of a fire suppression system. The sudden pipe movement was attributed to a pipe joint connection failure in a buried section of the pipeline. The failure was due to torque shear bolts at the joint connection that were not tightened, which was missed during the utility installation process and the work inspection prior to the incident.
Read the incident in this link
At 11:30 a.m. on June 20, 2007, Employees #1, #2, #3, and #4, who worked for Scaffolding Company, and Employees #5, and #6, who worked for Plant Services Company, and Employees #7 and #8, who worked for a chemical manufacturer, were hospitalized after being exposed to dimethyl sulfate (DMS) in the ethoxylation area where it was used in reactors 4 and 5. Employee #7 was an operator who moved bags containing chemicals into the area in order to add it to reactor 4. Employee #8 was a mechanic that worked unplugging an auger at reactor 4.
Employees #7 and #8 started working at 7 a.m. at reactor 4. Employees #1, #2, #3, and #4 dismantled a scaffold at a platform at the reactors. Employees #5 and #6 removed and installed new insulation on piping at a platform at the reactors. The host employer did not become aware that employees were exposed to DMS until about 2 p.m., when workers were discovered having chemical burns. Employees worked on a raised platform around the two reactors. In order to enter and leave the area, they walked along a path between two the reactors that was only 30 inches wide, and a pipe that contained DMS which ran overhead between the reactors. The piping system normally operated at 5 psi, but thermal expansion of DMS caused pressures over 300 psi and caused a valve on the overhead pipe to leak this extremely hazardous compound down onto employees that worked beneath the pipe.
Source:OSHA.gov
"Incidents relating to thermal fluid systems are unfortunately more common than we might realise,
and can be extremely serious. The fire and explosion hazards with thermal fluid systems have been
re-emphasised by recent incidents. These incidents have a direct bearing on the estimated 4,000 UK
companies that operate thermal fluid systems.
Water or steam can be used as heat transfer fluids, but when high temperatures are needed
organic fluids, which are capable of forming explosive atmospheres, are often used. Although
fire and explosion hazards of low flash point flammable liquids are generally recognised, similar
hazards with high flash point materials, such as thermal fluids, are often missed. These heat transfer
fluids are often handled at temperatures above their flash point.
However, many people are unaware that heat transfer fluids based on mineral oils
degrade over time. This degradation can cause the fluid’s flash point to decrease dramatically, so
that thermal fluids which were not flammable at the operating temperature when they were initially
installed may, over time, become flammable at the operating conditions. Also, high flash point
materials (such as thermal fluids), can form explosive mist atmospheres when handled under
pressure, even at temperatures below the flash point".
Read the article in this link.
"In this study, the explosion failure of a bellows expansion joint made of Type 304 stainless steel (UNS S30400) in a pipeline conducting methane (CH4) gas at 400 °C is analyzed. Using the simulation mechanical software, the behavior of the pipeline during the working condition was investigated.
Observations of the metallographic sections indicated that corrosion was involved in the cracking of the bellows that led to the explosion. After investigating the fracture surface, it was noted that the cracks occurred at dimples in the bellows. The presence of hydrogen sulfide (H2S) in the gas stream resulted in stress corrosion cracking".
Read the incident in this link
Employees #1 and #2 were engaged in a turnaround operation at a fertilizer manufacturing plant. They were standing on a work platform at a height of approximately 20 ft, removing an 18 in. diameter manway cover on the east monoethylamine stripper in Ammonia Plant #2. The top manway cover on the east stripper had already been removed and they were using a #5 spline drive, #3913 air-operated impact wrench to open the bottom manway cover. They had removed all but one of the bolts when there was a sudden flash fire and explosion. Employee #1 suffered broken bones and suffered second-degree burns over 60 percent of his body. He was killed. Employee #2 suffered minor burns on his arms and legs. The source of ignition is not known.
Source:osha.gov
An employee was cleaning the floors in a restaurant and mixed together sanitizer and heavy duty floor cleaner. The sanitizer contained chlorine and the floor cleaner contained ammonia which, when combined, creates chlorine gas. The chlorine gas was drawn into the ventilation system and circulated throughout the restaurant. Coworkers were evacuated when the white gas cloud formed, and three employees were taken to the hospital with respiratory problems.
Source:osha.gov
A road tanker loaded with ammonia hydroxide was being unloaded into a polyethylene storage tank at the site of a chemical distributor. This change was not taken through a MOC. The unloading was being accomplished by filling the vacant space above the liquid inside the tanker with compressed air, a standard method of unloading such tankers. When the tanker was emptied, the compressed air surged into the polyethylene storage tank, which was not designed to withstand that kind of pressure. The polyethylene tank ruptured, releasing a substantial volume of ammonia into the air. An employee, who was close to the drain valve on the tanker, inhaled a substantial volume of ammonia, He suffered serious chemical burns to his lungs, resulting in his death.
Source:osha.gov
The 109D-C was one of three identical vessels at the facility that removed moisture and carbon monoxide from a synthesis gas used in the manufacture of ammonia. The 109D-C, which had been taken off line to replace its desiccant material, had been online for approximately 11 1/2 hours when the vessel exploded into flame. One employee was killed instantly in the explosion and 6 more suffered severe burns. Another employee, a crane operator, suffered from severe burns and was hospitalized for several weeks before he died. An ammonia operator, was standing on the catwalk above the 109D-C when it exploded. He also suffered severe burns and died several weeks later. Subsequent inspection of the vessel revealed a cracked weld. Apparently, an inadequate repair job had been made to the weld two days before the accident.
Source:osha.gov
At approximately 7:10 a.m. on June 11, 2008, Operators at the C2 unit (Plant 2) in C building were injecting 60-psi steam at a temperature of approximately 400-degrees Fahrenheit into a precooler, heat exchanger Model Number E300-G, to purge the process of the latex products. Latex was on the tube side and ammonia was on the shell side. The steam was injected into the tubes heating the ammonia on the shell side. The precooler over pressured, rupturing the shell, releasing ammonia into the environment. Employee #1 was found dead beneath the debris in the area of the heat exchanger several hours after the explosion occurred. Five contracted employees were severely exposed to ammonia. Employees #2, #3, #4, and # 6 were hospitalized. Employee #5 received first aid and was released.
Source:OSHA.gov
How do you address human factors of lookalikes when handing over lines/ equipment for maintenance?
At approximately 9:00 a.m. on March 15, 2022, an employee disconnected nuts to a line for service and repair work. The employee was working to depressurize lines of ammonia for service work. The team had isolated, performed proper lockout/tagout, and bled the line assigned for work off. The employee began disconnecting nuts on the wrong line with pressure still on it. Pressurized ammonia began to leak from the pipe; the employee reacted to protect the plan and other personnel on-site, grabbed the nut, and manually screwed a few turns of the threads to stop the leaking. This action caused burns to the employee's hands that needed medical attention. The employee was not wearing his protective gloves because he was supposed to be working in the bled offline, which would have eliminated the hazard of glove use.
Source:OSHA.gov
Pyrophoric materials create fire and explosion hazard
There have been several explosions involving pyrophoric materials in storage tanks. It's important to take preventive measures when emptying tanks or vessels, or when opening equipment and piping for inspections and maintenance.
This bulletin explains how pyrophoric materials can form in tanks. It also describes how to prevent the explosions that can occur when pyrophoric iron sulfide is exposed to oxygen. Download and read the bulletin in this link
