On the morning of September 5, 2008, a plumber was called to A-1 Mushroom Substratum Ltd. in Langley, British Columbia. This was the second time in a few days.There, he found that the inlet pipe at the bottom of a pump shed was completely blocked…
On the morning of September 5, 2008, a plumber was called to A-1 Mushroom Substratum Ltd. in Langley, British Columbia. This was the second time in a few days.There, he found that the inlet pipe at the bottom of the pump shed was completely blocked, and informed the supervisor of the mushroom composting facility that a company with expertise in sewage pumping was needed.
Instead, under the guidance of the supervisor, two workers tried to clear the blockage of the butterfly valve in the pipeline.Within seconds of prying open the flange, a worker fell face down into the water at the bottom of the shed, believed to be due to the sudden release of hydrogen sulfide (H2S) gas in an oxygen-deficient environment.He will die.
In the next few minutes, two potential rescuers from the multi-employer mushroom planting and processing business will have a similar fate.The other two workers-fortunately-will suffer near-fatal, irreversible brain damage.
In the investigation report released at the end of November, WorkSafeBC will point out a series of failures in the design, construction and operation of the facility.The board of directors stated that the investigation may be “the most complicated in the history of WorkSafeBC.” “It will take months to visit key areas of the work site; it will take several months to fully understand the industrial processes involved and the events within five years. The chronological sequence of events and decisions that come into play.”
On that September day, two workers were trying to clear a blocked pipe in a recessed pump shed, while their supervisor was observing from a height of about three meters from the building entrance.Workers stood in the process water and sludge that had accumulated about 40 cm at the bottom of the shed, removed 8 corroded bolts from the flange of the valve, and loosely installed 4 new bolts to hold the valve in place.
At around 5 pm, one of the workers used a screwdriver to pry out the top flange from the valve, and then used another screwdriver to remove straw, sludge and other materials stuck in the valve.”A small amount of liquid started to flow out,” the WorkSafeBC investigation report in Richmond, British Columbia noted.
When the worker took off the straw, he complained to the supervisor about the smell, prompting the supervisor to let the worker leave the shed.
The worker at the valve took a step and then fell face down in the water and sludge.The supervisor climbed down and helped the second worker support the unresponsive employee to a sitting position against the shed wall.The supervisor then called the owner for emergency assistance.
When the paramedics arrived at about 5:20 pm, they found that the supervisor outside the shed had lost his way and was suffering from respiratory distress.”The ambulance crew noticed the unpleasant smell, suspected the dangerous atmosphere, and decided to retreat from the shed area,” WorkSafeBC reported, preventing other workers who reached with a ladder from entering the shed.
In total, five workers from the three companies that make up the processing facility-A-1 Mushroom Substratum, HV Truong Ltd. (a mushroom growing company) and Farmers’ Fresh Mushrooms Inc. (a packaging and marketing company) were removed from the shelter .Ut Van Tran, 35, Chi Wai Chan, 55, and Han Duc Pham, 47, died; Tchen Phan is still in a wheelchair and Michael Phan is in a coma.
WorkSafeBC’s report pointed out many shortcomings: the absence of an OH&S system on site; failure to correct the anaerobic (anaerobic) conditions generated in the process tank that pumps water through the pipeline, resulting in the accumulation of H2S in the inlet pipe; lack of protection against solids entering the pipeline Engineering controls; lack of regulatory compliance; deficiencies in the design, construction, and operation of facilities since 2004.
WorkSafeBC’s Director of Investigations Jeff Dolan said: “We recognize that these families have to wait a long time to learn more about what happened to their loved ones. The reasons are understood.”, said in a press release.
In August 2010, A-1 Mushroom Substratum, HV Truong, and 4 individuals received 29 occupational health and safety charges.In May of the following year, the two companies and three individuals pleaded guilty to 10 total counts of failing to ensure the health and safety of workers; providing workers with information, guidance, training and supervision; and ensuring that the dangers of confined spaces are eliminated or minimized And conduct related work in a safe manner.
The verdict last November ended with a fine of $200,000 for A-1 Mushroom Substratum (now bankrupt), $120,000 for HV Truong, and $15,000, 10,000, and $5,000 for the three.
Raj Chouhan, a labor critic of the New Democratic Party of British Columbia, is one of the choruses demanding a tougher sentence.Chouhan described the final punishment as a slap on the wrist. He reported that “these families really hope to get something to help other families and other workers from it.”
In order to explain the circumstances that led to the fatal incident, the process of composting mushrooms in the facility needs to be considered.In the 3-D animation model, WorkSafeBC pointed out that the piping system was constructed to supply fresh water and process water from a large independent water tank in the fenced area.The mixed water is then pumped through a series of pipes; first into the compost bin, and then sprayed onto the compost pile containing straw, chicken manure and agricultural gypsum.
However, due to operational issues and reduced compost production, the process water tanks and sealed areas are filled with process water, straw and sludge.To prevent the pumps and pipes from freezing in winter, the shed was built against the containment wall in 2007.
Also relevant is the design and construction of the process water circulation system, which draws process water from the bottom of the tank into the inlet pipe.The WorkSafeBC report stated that this resulted in blockages and anaerobic conditions in the piping system.
The report concluded: “Since straw and sludge have settled to the bottom of the tank, these materials will inevitably enter the pipeline and block the flow of water or form a blockage.”
Coupled with the reduced demand for process water-Langley town closed a composting barn in late 2007 due to regulatory violations-this means that the water entering the system stays longer, and the frequency of flowing through the pipes is reduced and increased To deal with the opportunity, water growth stagnates and supports anaerobic activity.
The report explains: “What makes the problem worse is the lack of a means to promote the circulation and uniform mixing of any oxygenated water entering the [process] tank with the accumulated water, sludge and solids at the bottom of the tank.”.
Les Mackoff, the defendant’s defense lawyer, said that the owners “work with these people every day and they feel terrible about this happening.”
Mackoff reported that before the fatal incident, the owner had hired experts and sought engineering advice on how to install biofilters to help minimize the possibility of odors.However, he pointed out that “the building is flawed. The facility has suffered a serious breakdown.”
Neil McManus is a certified industrial hygienist from NorthWest Occupational Health & Safety in Vancouver. He said his view is that engineers control occupational safety because “their designs create working conditions that affect others.”
McManus said that based on his experience, most composting operations have submersible pumps and removable pumps.He added that without these, people would have to enter “the room to repair the pump or something blocking it.”
David Nguyen, an agricultural health and safety expert at the Farm and Ranch Safety and Health Association (FARSHA) in Langley, British Columbia, said the incident “opened everyone’s eyes in this particular industry.” .Nguyen reported that he visited the workplace and has been working with employers after the incident to improve work-related health and safety.
He said that engineering issues are a problem, but he added that he thinks other things—such as preventive measures around confined space risk assessment, hazard identification, and exposure control—may help prevent accidents.
Reading these signs may also help prevent.About two months before that fatal day, on July 15, 2008, the British Columbia Farm Industry Review Committee received complaints from Town Councillor Charlie Fox and his wife about the smell and waste water from the composting operation.
The town has begun legal action, closing the facility for the second time.In fact, the court hearing for the second complaint is scheduled to be held three days after the accident.
“The tragedy happened where we knew the smell came out, because it was basically an uncovered sinkhole,” Fox argued.”In my opinion,” he said, “the problem is that the sludge comes out later and stays in these huge open sedimentation tanks.”
McManus reported that less than a year after the Langley incident, he visited another mushroom farm in British Columbia, where he saw the same “operating mechanism” and found “a surprisingly high concentration” at the pumping station. “H2S.
“We must leave there immediately,” he recalled.”Before the change, the smell was zero. My nose told me there was H2S here, and I looked around and didn’t see any changes to explain what was happening. That was the pump. We could see the foam at the bottom,” McManner Said.
He speculated that “foam floating above the liquid can capture at least one atmosphere of pressure”, some of which may be H2S.”This is a highly constrained system and highly unstable. So if you trap H2S molecules in a bubble in a thickened fluid, and apply some pure force to it and loosen the fluid, then the bubble has a solution Expelled,” he said.”The culprit soon passed… When investigators went to find the cause of the death, they could not find anything.”
WorkSafeBC’s report stated that when the town’s fire chief measured the air in the shed at about 5:30 pm, the hydrogen sulfide content was 36 parts per million (ppm) and the oxygen content was 15%-too high and too high, respectively. Low.After just 22 minutes, the gas content dropped to 6 ppm, and the normal oxygen content was 20.9%.
These concentrations are in sharp contrast to the WorkSafeBC count on January 29, 2009 (five months later), when the valve was removed and the air in the intake pipe below the valve was measured.“The H2S content exceeds 500 ppm (the maximum reading on the monitor), indicating that the anaerobic conditions in the pipeline may cause the H2S content to be high enough to cause unconsciousness and rapid death,” the investigation report noted.
Why did one worker in the shed become unresponsive within a few seconds after the release of H2S and later died, while the other survived?
“When you look at occupational hygiene, not everyone is affected by the same substances in the same way,” explains Shirley Gray, an occupational hygienist at the Nova Scotia Department of Labor and Higher Education in Halifax Say.”There are a lot of smokers there. Not everyone will get lung cancer,” Gray gave an example.
She said factors that may affect the response to exposure include ventilation, proximity to the point of release, and breathing rate.”A [worker] could have done more work and actively integrated into more environments than the others next to him,” she pointed out.
Gray reports that all gases will replace oxygen, but to do this, the concentration must be very high.”To replace 1% of the oxygen, you have to have a very high concentration,” she said, although another possibility might be an oxygen scavenger, “it actually binds the oxygen and takes it away from the atmosphere.”
McManus said that in 15% oxygen, “you will not have a serious impact on people’s viability.”"This is why it is likely that H2S did this,” he speculated.
These deaths prompted the New Democrats of Vancouver and the British Columbia Federation of Labor (BCFL) to repeatedly call for an investigation of the coroner.Chief Coroner Lisa Lapointe answered the call in December last year.
“After reviewing all available information in the case, including WorkSafeBC’s report, [Lapointe] concluded that it would be beneficial to conduct an investigation to examine some of the broader circumstances of the incident to prevent future deaths in similar circumstances. “A statement from the British Columbia Coroner Service, headquartered in Vancouver, stated.During the investigation scheduled to begin on May 7, the chief coroner Norm Liebel and the jury will hear testimony from numerous witnesses.
Raj Chouhan of the New Democratic Party said that he hopes some suggestions “can help us prevent such tragedies in the future.”
BCFL Chairman Jim Sinclair also welcomed the provincial investigation and pointed out in a statement that it “brought the hope of greater security for farms in British Columbia.”
The WorkSafeBC report stated that before the incident, “no one seemed to be concerned about the potential development of anaerobic conditions in the pipelines that form part of the process water recovery system, even if the rest of the system remains aerobic.”
“Although the industry and regulatory agencies recognize that gas production is a by-product of these operations, the industry literature focuses more on environmental protection and odor elimination, rather than the potential hazards generated during the production of these gases,” the report added.
Scott Fraser, the FARSHA project director, agreed that prior to the accident, the level of awareness of the dangers of mushroom composting operations was limited.”When it first happened, I don’t think anyone knew what really happened or the amount of hydrogen sulfide that might be shed from these things,” Fraser said.
He reported that since the incident, written information has been distributed to similar operations, and an exposure control plan for mushroom compost has been put in place.
Nguyen said that the workers at the Langley factory speak Vietnamese, and he speaks Vietnamese as his second language.”People who work in [agriculture] are often first-generation immigrants, so English is not always their first language.”
Post time: Dec-23-2021
