Asphxiation incident

Employees were tasked to fill a series of Chart MVE 1842P-150 Cryogenic Freezers in an enclosed storage room on a weekly basis. The room was not equipped with an adequate engineered ventilation system or oxygen monitoring equipment or system. On the evening of November 20, 2019, an employee began topping the bulk tanks off with liquid nitrogen when the room became filled with nitrogen gas causing the employee to collapse and eventually succumb to the oxygen-deficient atmosphere created in the room. The room was not equipped with an adequate engineered ventilation system or oxygen monitoring equipment or system. This condition exposed an employee to an oxygen deficient atmosphere while filling bulk tanks with liquid nitrogen. 

Source:OSHA.gov

Decomposition incident

 On September 21, 2003, Employee #1 and several coworkers were working at a chemical plant that deals with nitric oxide. On the day of the accident, a major leak occurred in a stainless steel distillation column. The nitric oxide leaked into the facilities surrounding vacuum jacket and into the atmosphere through a pump, which controls a high quality vacuum inside the jacket to minimize transmission of heat toward the cryogenic distillation columns. A brown cloud quickly formed and the temperature and the pressure inside the distillation column and its surrounding vacuum jacket began to rise. The leak was detected and the vacuum pump was turned off to halt the leakage of nitric oxide into the atmosphere, allowing the pressure inside the column and vacuum jacket to stabilize around 130 psi. Although stabilized, the pressure was far above the normal pressure of less than or equal to atmospheric pressure (14.7 psi). Approximately 3 hours later, an explosion occurred. The operation and process were destroyed, and debris flew through the plant. Employee #1 suffered lacerations due to flying glass and was treated at a local hospital, where he received stitches and then released. A detailed investigation determined that the cause of the explosion was most likely due to something inside the vacuum jacket initiated the dissociation of nitric oxide, a reaction that is very rapid, exothermic, and self-propagating once started. 

Source:Ohsa.gov

HAS YOUR HAZOP STUDIED THIS POSSIBILITY?

 On April 2, 2003, Employee #1 and a coworker, the technicians, were watching a polymerization process involving styrene and acrylonitrile monomers. Employee #1 and the coworker's jobs involved monitoring a reactor vessel throughout the process. At the end of the batch process, non-polymerized monomer and vapors were stripped from the reactor through a condenser system to a distillate collection tank and were ultimately charged to subsequent batches. Toward the end of the stripping process, Employee #1 left the control room to determine if enough distillate had been removed to allow the remaining water and mixture to be dumped to the "dirty" sewer and a collection system. While Employee #1 was in the vicinity of the reactor, an explosion occurred in a small auxiliary charge tank. A piece of metal struck Employee #1's abdomen and killed him. Although the charge tank was not in use at the time of the accident, a small amount of the batch had back-flowed through a valve between the reactor and the auxiliary tank during the reactive process. The batch continued to react in the auxiliary tank, overheating and overpressurizing the tank. 

Source:Osha.gov

WHERE DO YOUR RUPTURE DISCS VENT?

 Employee #4 was cleaning the #6 chemical reactor on July 19, 1990, with a flammable mixture of solvents when the reactor burst its rupture disc and the mixture was expelled into the plant. The solvent ignited and the vapor cloud explosion resulted in the plant's 43 employees being injured by flying debris and/or being thrown by the force of the explosion. Employee #4 eventually died from his burns. Employee #1, a maintenance employee, was moving away from the area when he was struck in the head and killed by debris flung during the explosion. 

Employees #3, #6, #7, #8, #9, #16, and #19 were located in the manufacturing offices in Building 4, about 75 ft south of the reactor. Employees #2, #10, #11, #12, #14, #15, and #17 all worked in Building G, 50 to 75 ft southwest of the reactor and were leaving when the explosion either threw debris at them or threw their bodies onto equipment or debris. Employee #5 was in the same building as the reactor and was thrown down by the explosion, sustaining burns and crushing injuries. Employee #13 sprained his knee while moving from the break room to the courtyard, about 100 ft southeast of the reactor. Employee #18 suffered a sprained left thigh and a bruised shoulder. 

It appeared that the reactor was not vented to a safe location and had primitive temperature controls, and the company did not enforce the mandatory attendance of operators at the reactors during operation. All of these factors, including minimal operating procedures (none specifically for cleaning), led to the explosion and the resulting extensive injuries and property damage. 

Source:Osha.gov

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Process Control Basics: We Provide Tools and Basic Information for Learning Process Instrumentation Electrical and Control Engineering.

CAMPAIGN AGAINST ASPHYXIATION

 https://www.linde-gas.com/en/images/Campaign%20against%20asphyxiation_tcm17-13907.pdf 

Share this newsletter with all your employees and contractors. It may save a life.

COLD BURN INCIDENT

On Tuesday 17th May, a worker received serious cryogenic burns after immersing their hands in a container of liquid nitrogen whilst trying to shrink a brass bush for inserting into an excavator boom arm.

How did it happen? 

The worker was not wearing the correct personal protective equipment for the task. Further details related to the incident are not available at this time 

Key issues

Liquid Nitrogen

Liquid nitrogen is one of the cryogenic liquids commonly used in the mining industry. As “cryogenic” means related to very low temperature, it is an extremely cold material. Liquid nitrogen has a boiling point of negative – 195.8 degrees centigrade and can expand to a very large volume of gas.

The vapor of liquid nitrogen can rapidly freeze skin tissue and eye fluid, resulting in cold burns, frostbite, and permanent hand and eye damage, even by brief exposure.

Liquid nitrogen expands 695 times in volume when it vaporises and has no warning properties such as odour or colour. Hence, if sufficient liquid nitrogen is vaporised to reduce the oxygen percentage to below 19.5%, there is a risk of oxygen deficiency which may cause unconsciousness. Death may result if oxygen deficiency is extreme. To prevent asphyxiation hazards, handlers must make sure that the work area is well ventilated.

Without adequate venting or pressure-relief devices on the containers, enormous pressures can build upon evaporation. Users must make sure that liquid nitrogen is never contained in a closed system. Use a pressure relief vessel or a venting lid to protect against pressure build-up.

Handling Safety Practices

Liquid nitrogen should be handled in well-ventilated areas.
Handle the liquid slowly to minimize boiling and splashing.
Use tongs to withdraw objects immersed in liquid nitrogen - Boiling and splashing always occur when charging or filling a warm container with liquid nitrogen or when inserting objects into the liquid.
Use only approved containers. Impact resistant containers that can withstand the extremely low temperatures should be used. Materials such as carbon steel, plastic and rubber become brittle at these temperatures.
Only store liquid nitrogen in containers with loose fitting lids (Never seal liquid nitrogen in a container). A tightly sealed container will build up pressure as the liquid boils and may explode after a short time.
Never touch non-insulated vessels containing liquid nitrogen. Flesh will stick to extremely cold materials. Even non-metallic materials are dangerous to touch at low temperatures.
Never tamper or modify safety devices such as the cylinder valve or regulator of the tank.
Liquid nitrogen should only be stored in well-ventilated areas (do not store in a confined space).
Do not store liquid nitrogen for long periods in an uncovered container.
Cylinders should not be filled to more than 80% of capacity, since expansion of gases during warming may cause excessive pressure build-up.

Eye / Face ProtectionSuitably rated full face shield over safety glasses or chemical splash goggles are recommended during transfer and handling of liquid nitrogen to minimise injuries associated with splash or explosion.

Skin Protection

Suitably rated, loose-fitting thermal insulated or leather gloves, aprons, long sleeve shirts, and trousers without cuffs should be worn while handling liquid nitrogen. Safety shoes are also recommended while handling containers. Gloves should be loose-fitting, so they are able to be quickly removed if liquid nitrogen is spilled on them. Insulated gloves are not made to permit the hands to be put into liquid nitrogen. They typically only provide short-term protection from accidental contact with the liquid.

Source: https://www.rshq.qld.gov.au/safety-notices/mines/use-of-liquid-nitrogen-in-the-mining-industry

NITROGEN ASPHYXIATION INCIDENT

At approximately 2 a.m. on August 8, 2001, Employee #1 was working on top of a reactor under nitrogen purge. A coworker was wearing breathing air with a communication device. The lead man was on top of the reactor overseeing the job. The lead man turned around and began communicating on the headset with the workers monitoring the breathing air. Employee #1 walked past the lead man and the coworker without breathing air and reached into a manhole. Employee #1 was overcome by the fumes/vapors and fell 3 to 4 feet into the reactor. The coworker and lead man pulled Employee #1 out of the reactor, and the lead man performed CPR until the rescue team arrived. Employee #1 was pronounced dead at the hospital. Employee #1 died from asphyxiation. 

Source:Osha.gov

PIGGING INCIDENT

At approximately 8:00 a.m. on June 25, 2012, an employee was at the side of the pig launcher. The process was to purge the line of carbon gas with nitrogen. The nitrogen was pumped by a rig used to frac wells. The pump truck was capable of creating pressures which were several times greater than the launcher was designed and built for. 

The employee had several responsibilities some of which were to check the joints of black pipe feeding the nitrogen. This entailed pouring soap water on the joints and check for bubbles. He was also responsible for watching the pressure gauges on the launcher, getting the line purged so the pigging operation could start, and opening and closing the ball valves in the line t o provide for proper flow. He had just spoken to another employee while looking at the gauges on the launcher when the launcher ruptured. The ball valve leading to the 16-in. main line was not open. The pump truck had been pushing nitrogen into the small pig launcher instead of over three mile long pipeline. The gauges were not reading any pressure at all and when the pump truck kicked up the pressure, the launcher ruptured. The launcher was shot over 800 feet away. 

The main part of the vessel struck another employee killing him instantly. 

Source:Osha.gov

EVEN A SMALL AMOUNT OF WATER CAN KILL

Employee #1 and a helper entered a lift station to unclog the system. Employee #1 called out to the helper that he was having trouble breathing and needed help exiting the lift station. The helper inserted the
ladder into the lift station and attempted to help Employee #1 climb up but could not hold on to him because his hand was slippery. Employee #1 slumped into the bottom of the lift station and his mouth and nose were partially submerged in the water. He was transported by emergency services to the hospital where he died of respiratory failure resulting from sewage water in his lungs

Emergency Isolation for Hazardous Material Fluid Transfer Systems – Applications and Limitations of Excess Flow Valve

 https://archive.epa.gov/emergencies/docs/chem/web/pdf/efv_alert.pdf

ARE YOU IDENTIFYING ALL SOURCES OF ENERGY FOR LOTOTO?

On October xx, 2009, an employee was working for the XXX Public Utilities Commission-Wastewater Enterprise as a trainee. There were four people to perform preventive maintenance for the fans at the wastewater treatment plant that day. The employee and a Coworker #1 were servicing the fans in Room Number 201 while the foreman and Coworker #2 were in an adjacent room. There were four supply fans. The employee was working onXX1-1 while Coworker #1 was working on an adjacent fan.
The fans were shut down, tagged-out, and locked-out. The employee proceeded to remove the enclosure metal guard to expose the belt and pulley drive for the inspection. Although the fan was tagged and locked- out, it was not blocked-out. The exhaust fans in a room below were not stopped. Their operation created an airflow which traveled through the same duct system as for the supply fans upstairs. The air flow through the duct caused the supply fan blades to spin freely. The fan blades were not blocked before servicing. At approximately 8:30 a.m., when the employee was removing the enclosure guard for the V-belt and pulley drive of the spinning fan, the in-running nip point amputated his left middle finger. He
screamed as Coworker #1 came to his aid. He was taken to XXX Hospital by Coworker #1. He was treated and released the same day.

3 Employees Killed, 2 Injured By Hydrogen Sulfide Exposure

 Employee #1 was inside a frac tank shoveling residue (called BS) to one end of the tank for subsequent vacuuming and removal. As he completed the task, the tank was washed down with waste water containing hydrogen sulfide. Approximately 8 minutes following the waste water entrance, Employee #1 collapsed from exposure to the chemical. Employee #2 entered the tank and attempted to rescue Employee #1, but he too collapsed. Apparently Employees #3 and #4 entered the tank and attempted a rescue and but succumbed also. Employee #5 attempted to revive Employee #1 through an opening at the end of the frac tank. He was affected by the hydrogen sulfide gas but was able to call the city's first responders. Employees #1, #3, and #4 died of hydrogen sulfide exposure. Employees #2 and #5 were hospitalized. 

Source:Osha.gov

EXPLOSION IN SALT WATER TANK

At approximately 2:30 a.m. on July 30, 2011, Employee #1 was working the night shift at a saltwater disposal facility. Specifically, the facility specializes in the disposal of salt water that is contaminated with field oil waste. The water would usually be separated from the oil and petroleum based materials in a settling tank. The water would then pumped back into the ground through an injection well, while the oil based material is gravity drained into a series of collection tanks. The oil would then sold to oil recyclers. During Employee #1's shift, he was monitoring two oil collection tanks that were connected to a separation drum tank. 

The first of the two tanks was also connected to the second tank to allow for spillover as the amount of liquid rose. Under normal operation, the tanks would take several days to become full; however, facility operators would frequent the catwalk area that was accessed by way of a ladder to gauge the tanks levels. After receiving a water delivery from a full tanker-truck, Employee #1 accessed the catwalk to gauge the water level. Soon after reaching the tank area, an explosion occurred. The truck driver, who was leaving the facility, observed the explosion and following fireball in his rear view mirror. The driver immediately stopped his truck and contacted emergency services. Despite the fire spreading to both tanks, Employee #1 was able to escape the fire crazed area; however, his clothes were completely burned off and over ninety percent of his body was burned. Employee #1 collapsed on the front porch area of the facility office, where emergency personnel, a short time later, began treatment. Employee #1 was taken by helicopter to Ardmore Hospital, where he died. The accident investigation revealed that Employee #1 had a history of smoking near the storage tanks and had been warned by the employer to stop several times. 

Source:Osha.gov

"Sewage systems on vessels are known as Marine Sanitation Devices (MSDs) or Collection, Holding and Transfer Tanks (CHTs). Cleaning these systems is required for operations such as routine surveys and surface preservation, equipment modification, repairs and maintenance. Entering and cleaning
sewage tanks, piping and components present specific hazards to workers that put them at risk for injuries and illnesses if they are not properly protected (29 CFR 1915.13).
Workers are often exposed to dangerous atmospheres during tank opening and venting; manual pumping and stripping; breaking or dismantling components and piping; and pressure
washing, mucking, and scaling (29 CFR 1915.11(b); 1915.12). A dangerous atmosphere may expose workers to the risk of death, incapacitation, injury, chronic or acute illness, or impaired ability
to escape unaided from a confined or enclosed space (29 CFR 1915.11(b)). When working on CHTs/MSDs, special attention should be given to good hygiene practices, proper use of personal
protective equipment and safe confined space entry procedures (29 CFR 1915.88; 1915 Subparts B & I).
The information in this document can help prevent exposing workers to the known and unknown dangers of handling treated or untreated sewage and gray water tanks during tank opening, entry,
cleaning and related operations. Related components/operations include: piping, aeration, vacuuming, settling, and treatment tanks and apparatus; sewage-contaminated water tanks or waste oil
tanks, bilges, or sumps; and valves, pumps, grinders, macerators and other contaminated equipment".

https://www.osha.gov/sites/default/files/publications/OSHA_FS_3587.pdf

Source:Osha.gov

CHLORINE EXPOSURE INCIDENT

 On April 2, 2002, Employee #1 and a coworker, employees of a water treatment plant as waste water treatment operators, were changing out five 1-Ton cylinders, located in a chlorine cylinder room. Employee #1 attempted to disconnect the yoke number two of the five 1-Ton cylinders, but a high pressure leak of chlorine gas escaped from the cylinder into his breathing zone. Employee #1 was able to immediately tighten the yoke connection, stopping the leak, but required the coworker to finish the task. With Employee #1 sitting to the side, the coworker, after a couple of attempts, was able to disconnect the yoke connection without any further chlorine gas escaping. After notifying management of the incident, the coworker drove Employee #1 to Hospital Emergency Room. Once admitted, Employee #1 was treated for chlorine gas exposure and diagnosed with bilateral lower lobe pneumonia.

 A 42-year-old laborer leak testing joints inside a 54-inch round pipe suffered fatal blunt force injuries in October 2015, when an inflatable ¿bladder¿ ruptured at a waste-water treatment plant. Inspectors from the U.S. Department of Labor¿s Occupational Safety and Health Administration found his employer failed to train him properly on the testing procedure.

Workers can be killed when employers fail to protect construction workers from the many dangers in confined spaces, said Assistant Secretary of Labor for Occupational Safety and Health Dr. David Michaels. These are among the first citations under OSH¿s new Confined Space Standard. Employers can prevent more tragedies like this one if they ensure proper training of workers and communication among multiple employers whose workers are on the same site.

In August 2015, OSHA implemented its confined space in construction standard after research showed proper safety procedures would protect hundreds of workers each year from life-threatening hazards. Hazards include the risks of toxic exposure, electrocution, explosion and asphyxiation present for workers in confined spaces such as pipes, manholes, crawl spaces and tanks. In an emergency, it can be difficult to exit these spaces quickly or for rescuers to enter safely.

The agencys investigation also found the four companies failed to continuously monitor confined spaces for atmospheric and other hazards and train workers in hazards. 

Source:Osha.gov

ARE YOU PERFORMING YOUR PSSR'S CORRECTLY?

A closure of an UV (shutoff valve) was provided in the design of the plant, to avoid two phase flow when carryover occurred.  During an abnormality, the shutdown system activated the UV but the UV did not close. The RCA revealed that the UV did not close due to excessive friction caused by the presence of construction debris left behind that prevented the UV from closing

WASTE WATER TANK INCIDENT

On September 9, 2003, Employees #1 and #2 were extending the guardrail system to the hatch and platform area on top of a tank located on the Brewery property. The tank was used for the storage of solid waste at the waste water treatment facility. The tank was 40 ft in height and 48 ft in diameter. The employees were arc welding the guardrail system, 40 ft above the ground, when an explosion occurred. Employee #1 fell to the ground receiving fatal injuries. Employee #2 fell to the inside of the tank, an opening of approximately 10 ft left due to the explosion. The tank had to be drained in order to recover the body. Employee #2 apparently died from injuries due to the explosion

Credit:Osha.gov