Showing posts with label Safe work practices. Show all posts
Showing posts with label Safe work practices. Show all posts

August 12, 2022

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

August 8, 2022

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

July 23, 2022

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.

July 19, 2022

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

July 11, 2022

"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

May 23, 2022

CONTROL HAZARDOUS ENERGY

 https://www.aiche.org/ccps/control-hazardous-energy-lock-out-and-tag-out

"Lock-out and tag-out (LOTO) is a critical part of a strong all-around safety program. In LOTO, maintenance employees work with production employees to positively prevent all forms of hazardous energy from causing harm. Hazardous energy comes in many forms. Electrical energy can cause electrocution and burns, provide ignition to flammable atmospheres, and activate mechanical equipment. Steam can cause burns or initiate hazardous reactions. Nitrogen can cause asphyxiation. Chemical flow can cause uncontrolled reaction and injury. When a piece of equipment is being worked on, all sources of hazardous energy must be securely and positively locked out until the equipment is operational. Untold numbers of major process safety incidents and individual injuries have been caused by failure of LOTO. A prime example is the Bhopal catastrophe, one of the worst incidents ever to have occurred, which was caused in part by the failure of LOTO. Recently, a company process safety manager called CCPS asking for help in persuading a newly acquired facility within his company to implement a LOTO program. The manager was frustrated because, as the plant director stated, “We understand completely that maintenance workers are endangered if power or material flow were allowed to equipment they are servicing. That’s why no one would ever activate a switch or valve during a maintenance activity. LOTO is just extra, unnecessary work.” The company process safety manager knew that with the plant director’s attitude, the plant could be on the road to disaster. Could CCPS help him make the case for LOTO? At CCPS, we firmly believe that it is better to learn from the mistakes of others rather than to learn by painful, personal experience. So we asked CCPS member companies to give us examples of accidents caused by LOTO failures, and to provide testimonials about the importance of LOTO. The purpose of this article is to share this information with you, to help you lead the implementation or improvement of LOTO in your
company. A brief overview of LOTO procedures and tools are provided, as are references to more detailed resources." 

Reference: https://www.aiche.org/ccps/control-hazardous-energy-lock-out-and-tag-out

May 10, 2022

SAFE ACCESSING OF PRESSURE VESSELS

 https://www.kan.de/en/publications/kanbrief/industry-40-vision-or-reality/safe-accessing-of-pressure-vessels

"Operatives and technicians must frequently climb into pressure vessels in order to perform construction, maintenance, repair and inspection work. However, the access points through which they must pass for this purpose are often so small that although access is possible, rescuing these personnel in the event of an accident presents considerable difficulties. The Polytechnic University of Milan has conducted a number of studies into this issue in the course of two degree theses."

SEE THE LINK FOR FULL ARTICLE

November 22, 2021

New Lockout-Tagout Program Improves Safety

New Lockout-Tagout Program Improves Safety: To improve overall employee safety across plants and facilities, switch from a tagout-based safety program to a lockout-tagout (LOTO) program.

April 11, 2021

Two Employees Receive Corrosive Burns From Sanitizing

 At 12:00 p.m. on April 19, 2019, Employee #1 and Employee #2 were observing a food establishment's sanitation and cleaning process during an investigation. During the observations of the employees and processes, they used a foaming cleanser, quaternary ammonium, and a spot acid clear for cleaning and sanitizing. A pungent smell believed to be chlorine was being released into the air. Employees #1 and #2 noted that their eyes, skin, and mucosal linings of the mouth, throat, and nose were irritated and burning. Employee #2 measured the quaternary ammonium solution, and it was found to be in excess of 200 PPM, which is higher than recommended levels. Hospitalization was not required. 

Source:osha.gov

March 22, 2021

OSHA STANDARD FOR BREATHING AIR

OSHA Standard 29 CFR 1910.134(i)(1)
“Compressed breathing air shall meet at least the requirements for Grade D breathing air described in ANSI/Compressed Gas Association Commodity Specification for Air, G-7.1-1989, to include:
Oxygen content (v/v) of 19.5% - 23.5%;
Hydrocarbon (condensed) content of 5 milligrams per cubic meter of air or less;
Carbon monoxide (CO) content of 10 parts per million (ppm) or less;
Carbon dioxide (CO2) content of 1,000 ppm or less; and
Lack of noticeable odor”

March 18, 2021

OSHA'S RECOMMENDATIONS TO PREVENT INADVERTENT HOOKING UP OF BREATHING AIR INTO NITROGEN SYSTEMS

To help ensure that workers do not inadvertently hook up to inert gas supplies, the following recommendations should be implemented:

•Ensure that all requirements related to respiratory protection as outlined in29 CFR 1910.134 are met. Written standard operating procedures governing the selection and use of respirators must be developed and implemented. Requirements for training and instruction in the proper use of respirators and their limitations must be met at all facilities.

•Ensure (determine) that the couplings of the respirator air lines are incompatible with any other couplings/fittings for non-respirable air or gas delivery systems.Replace couplings on non-breathing air systems with another, incompatible type of coupling.

•Ensure that breathable air systems are not in any way interconnected to non-breathable air systems.

•Develop a maintenance procedure to address supply-line identification (labeling)and painting. Stress the purpose of color coding and the importance of completing detail painting in a timely fashion to ensure that this visual cue is always available to aid workers.

Source: Osha.gov

March 14, 2021

INCIDENT #3 DUE TO CONNECTING BREATHING AIR HOSE TO NITROGEN

 An employee hooked the fresh air line of his supplied-air respirator into a plant’s compressed airlines and began abrasive blasting. The plant operators, unaware that their plant air was being used as breathing air, shut down the fresh air compressor for routine, scheduled maintenance and pumped nitrogen into the system to maintain pressure and control the valves in the refinery. The employee was overcome by the nitrogen in the airlines and died of nitrogen asphyxia.

Source:Osha.gov

March 10, 2021

INCIDENT #2 DUE TO CONNECTING BREATHING AIR HOSE TO NITROGEN

An employee was using an air hammer to chip residue out of a furnace at an aluminum foundry.He was wearing an air-line respirator. Two compressed gas lines with universal access couplings were attached to a nearby post. The one on the right was labeled “natural gas.” The gas line on the left had a paper tag attached with the word“air” handwritten on it; however, this line actually contained pure nitrogen. A splitter diverted one part of the gas stream to the air hammer and the other part of the stream to the air-line respirator.The employee was asphyxiated and killed when exposed to pure nitrogen.

Source:osha,gov

March 5, 2021

INCIDENT #1 DUE TO CONNECTING BREATHING AIR HOSE TO NITROGEN

A contractor crew was assigned to abrasively blast inside a reactor vessel at a petrochemical refinery.Although verbal company policy called for contractors to supply all breathing air, this crew,with supervisor’s knowledge, had on several occasions used plant air to supply breathing air. A crew member mistakenly hooked up his air-line respirator to an unlabeled nitrogen line (only the shut-off valve was labeled) used by the refinery for purging confined spaces. Plant nitrogen and airlines were identical, and both had couplings compatible with the coupler on the respirator. The crew member was killed.

Source: osha.gov

November 21, 2020

Fire due to welding operation

A fire started at the manhole of an inspection pit for underground pipes of a petroleum storage depot during a welding operation as part of maintenance work on the piping supplying a tank. The underground pipes were feeding eleven tanks in different conditions. At 11:15 a.m., a leak of premium-grade gasoline occurred, followed by a sudden flash. Site technicians attempted to extinguish the ensuing pool fire. The operator activated the internal emergency plan, issued the order to close all motorised valves and called for assistance from petroleum industry partners. At 14.00, emergency responders were still unsuccessful in suffocating the fire with sand. At 15:20 an explosion occurred which was caused by two acetylene cylinders used in the welding operation. Fed by an unknown source, the fire continued to rage for several hours despite firefighting interventions. Eventually, the foot valve on the adjacent gasoline tank was found open by the firefighters. After its closure, the fire receded Intervention efforts were substantial and the toll quite heavy; 15 firemen were burned during the accident: 2 of them were badly hurt, 5 seriously and 8 slightly. Apparently, the firemen suffered burn injuries due to a gust of wind and for the cylinders' explosion. The entry valve of the adjacent tank was left open for an unknown reason.

Important findings
• According to the site director, the piping should have been submerged in water during the onsite works and therefore was omitted from the valve closure checklist and control diagram.

Firefighters encountered myriad difficulties, in particular:
• The fire route to the tank was submerged under a layer of burning hydrocarbons;
• Fire water pipes burst under the weight of vehicles evacuating the zone;
• Lack of information about the source of the fire.

Lessons Learned
• The accident scenario was not included in the site’s risk assessment study. Fires initiated from welding operations are abundant in the literature.  A hazard assessment of tank maintenance operations should examine all possible ignition scenarios (what if?) associated with hot work.
• In order to prevent subsequent fires or explosions to occur, ignition sources, such as the acetylene cylinders should be removed from the area of emergency operation.
• Operators should provide accurate information on location of safety instrumentation to the emergency responders as soon as possible, especially if such devices can contribute to the fire or explosion.

Source: European commission

July 14, 2020

Incident due to improperly ventiliated confined space

When I was a shift engineer, I entered a confined space, a pressure vessel, after obtaining necessary work permit. After I entered, I climbed up the internal fixed ladder to inspect a demister located at the top. As I was climbing up, the CO alarm in my personal gas monitor went off and I evacuated the vessel. Investigation determined that  during the purging process after plant shutdown, one part of an isolated pipeline connected with the vessel had not been been purged. When a valve connected to this pipeline was opened by an operator when I was inside, the pocket of trapped gas entered the vessel.
Lesson: Confined space entry can pop up surprises, even after receiving work permit. Ensure your personal gas monitor is working properly before you enter a confined space. It saved my life!

July 4, 2020

Have you assessed all the hazards?

Many accidents and fatalities occur during the erection of new equipment in chemical plants. These can include storage tanks. Double wall, double integrity storage tanks are often used for storing cryogenic liquids. In an incident mentioned by osha.gov, An employee was blowing insulation into the annular space of a newly constructed liquefied natural gas tank. He apparently accidentally fell into the space, which was full of perlite. He was engulfed by the perlite and was asphyxiated. Perlite is an insulation material. When a job hazard analysis is carried out, do you consider asphyxiation hazards due to insulation, in double wall tanks?