The US Chemical Safety Board released a safety bulletin intended to inform industries that use anhydrous ammonia in bulk refrigeration operations on how to avoid a hazard referred to as hydraulic shock. The safety lessons were derived from an investigation into a 2010 anhydrous ammonia release that occurred at Millard Refrigerated Services, Inc., located in Theodore, Alabama.
The accident occurred before 9:00 am on the morning of August 23, 2010. Two international ships were being loaded when the facility’s refrigeration system experienced “hydraulic shock” which is defined as a sudden, localized pressure surge in piping or equipment resulting from a rapid change in the velocity of a flowing liquid. The highest pressures often occur when vapor and liquid ammonia are present in a single line and are disturbed by a sudden change in volume.
This abnormal transient condition results in a sharp pressure rise with the potential to cause catastrophic failure of piping, valves, and other components—often prior to a hydraulic shock incident there is an audible “hammering” in refrigeration piping. The incident at Millard caused a roof-mounted 12-inch suction pipe to catastrophically fail, resulting in the release of more than 32,000 lb of anhydrous ammonia.
The release led to one Millard employee sustaining injuries when he fell while attempting to escape from a crane was after it became engulfed in the traveling ammonia cloud. The large cloud traveled a quarter mile from the facility south toward an area where 800 contractors were working outdoors at a cleanup site for the Deepwater Horizon oil spill. A total of 152 offsite workers and ship crewmembers reported symptomatic illnesses from ammonia exposure. Thirty-two of the offsite workers required hospitalization, four of them in an intensive care unit.
Chairperson Rafael Moure-Eraso said, “The CSB believes that if companies in the ammonia refrigeration industry follow the key lessons from its investigation into the accident at Millard Refrigeration Services, dangerous hydraulic shock events can be avoided—preventing injuries, environmental damage, and potential fatalities.”
Entitled, “Key Lessons for Preventing Hydraulic Shock in Industrial Refrigeration Systems” the bulletin describes that on the day before the incident, on August 22, 2010, the Millard facility experienced a loss of power that lasted over seven hours. During that time the refrigeration system was shut down. The next day the system regained power and was up and running, though operators reported some problems. While doing some troubleshooting an operator cleared alarms in the control system, which reset the refrigeration cycle on a group of freezer evaporators that were in the process of defrosting. The control system reset caused the freezer evaporator to switch directly from a step in the defrost cycle into refrigeration mode while the evaporator coil still contained hot, high-pressure gas.
The reset triggered a valve to open and low temperature liquid ammonia was fed back into all four evaporator coils before removing the hot ammonia gas. This resulted in both hot, high-pressure gas, and extremely low temperature liquid ammonia to be present in the coils and associated piping at the same time. This caused the hot high-pressure ammonia gas to rapidly condense into a liquid. Because liquid ammonia takes up less volume than ammonia gas—a vacuum was created where the gas had been. The void sent a wave of liquid ammonia through the piping—causing the “hydraulic shock.”
The pressure surge ruptured the evaporator piping manifold inside one of the freezers and its associated 12-inch piping on the roof of the facility. An estimated 32,100 lb of ammonia were released into the surrounding environment.
Investigator Lucy Tyler said, “The CSB notes that one key lesson is to avoid the manual interruption of evaporators in defrost and ensure control systems are equipped with password protection to ensure only trained and authorized personnel have the authority to manually override systems.“
The CSB also found that the evaporators at the Millard facility were designed so that one set of valves controlled four separate evaporator coils. As a result, the contents of all four coils connected to that valve group were involved in the hydraulic shock event—leading to a larger, more hazardous pressure surge.
As a result, the CSB notes that when designing ammonia refrigeration systems each evaporator coil should be controlled by a separate set of valves.
The CSB found that immediately after discovering the ammonia release, a decision was made to isolate the source of the leak while the refrigeration system was still operating instead of initiating an emergency shutdown. Shutting down the refrigeration system may have resulted in a smaller release, since all other ammonia-containing equipment associated with the failed rooftop piping continued to operate.
A final key lesson from the CSB’s investigation is that an emergency shutdown should be activated in the event of an ammonia release if a leak cannot be promptly isolated and controlled. Doing so can greatly reduce the amount of ammonia released during an accident.
How to Implement OSHA’s Globally Harmonized Hazard Communication Standard (GHS)
OSHA has issued a final rule revising its Hazard Communication Standard, aligning it with the United Nations’ globally harmonized system (GHS) for the classification and labeling of hazardous chemicals. This means that virtually every product label, safety data sheet (formerly called “material safety data sheet” or MSDS), and written hazard communication plan must be revised to meet the new standard. Worker training must be updated so that workers can recognize and understand the symbols and pictograms on the new labels as well as the new hazard statements and precautions on safety data sheets.
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Poor Design and Failure to Test Dust Collection System Among Causes of US Ink New Jersey Flash Fire that Burned Seven Workers
The flash fire that burned seven workers, one seriously, at a US Ink plant in New Jersey in 2012 resulted from the accumulation of combustible dust inside a poorly designed dust collection system that had been put into operation only four days before the accident, an investigation by the US Chemical Safety Board (CSB) has found.
US Ink is a subsidiary of Sun Chemical, a global graphic arts corporation which has some 9,000 employees worldwide. US Ink manufactures black and color-based inks at seven US locations including East Rutherford, New Jersey. A key step in the ink production process is mixing fine particulate solids, such as pigments and binders, with liquid oils in agitated tanks.
CSB Chairperson Rafael Moure-Eraso said, “The findings presented in the CSB report under consideration show that neither US Ink nor its international parent company, Sun Chemical, performed a thorough hazard analysis, study, or testing of the system before it was commissioned in early October 2012. The original design was changed, the original company engineer retired prior to completion of the project, and no testing was done in the days before the operation of the black-ink pre-mixing room production was started up.”
The CSB found that the ductwork conveyed combustible, condensable vapors above each of three tanks in the mixing room, combining with combustible particles of dust of carbon black and Gilsonite used in the production of black ink.
Investigation Supervisor Johnnie Banks said, “The closed system air flow was insufficient to keep dust and sludge from accumulating inside the air ducts. But to make matters worse, the new dust collector design included three vacuuming hoses which were attached to the closed-system ductwork, used to pick up accumulated dust, dirt, and other material from the facility’s floor and other level surfaces as a ‘housekeeping’ measure. The addition of these contaminants to the system ductwork doomed it to be plugged within days of startup.”
The report describes a dramatic series of events that took place within minutes on October 9, 2012. About 1 p.m., an operator was loading powdered Gilsonite, a combustible carbon-containing mineral, into the bag dump station near the pre-mixing room when he heard what he called a strange, squealing sound. He checked some gauges in the control room, and as he was leaving he saw a flash fire originating from the bag dump where he had just been working. He left to notify his supervisor. At about that same time, other workers heard a loud thump that shook the building.
In response to the flash from the bag dump station and the thump, workers congregated at the entrance to the pre-mix room. One worker spotted flames coming from one of the tanks. He obtained a fire extinguisher but before he could use it, he saw an orange fireball erupt and advance toward him. He squeezed the handle on the extinguisher as he jumped from some stairs, just as the flames engulfed him and six other employees who were standing in the doorway.
The CSB determined that overheating and spontaneous ignition which likely caused the initial flash fire at the bag dump was followed by ignition of accumulated sludge-like material and powdery dust mixture of Gilsonite and carbon black in the duct work above tank 306. Meantime, the dust collection system, which had not been turned off, continued to move burning material up toward the dust collector on the building’s roof, where a sharp pressure rise indicated an imminent explosion. This was contained by explosion suppression equipment, but the resulting pressure reversed the air flow, back to the pre-mix room, where a second flash fire occurred, engulfing the workers.
Investigation Supervisor Banks said, “The new system was not thoroughly commissioned. There was no confirmation of whether the system would work as configured, missing opportunities to find potential hazards. The design flaws were not revealed until the dust explosion.”
The report’s safety management analysis points to a lack of oversight by company engineers of the work done by installation contractors. The company chose not to perform a process hazard analysis or management of change analysis—required by company policy for the installation of new processing equipment—because it determined it was merely replacing a previous dust collection system in kind. However, the new system in fact was of an entirely different design.
Considering the emergency response following the flash fire and dust collector explosion, CSB Investigators found that while workers had received training in emergency response situations, they did not follow those procedures, because US Ink had not developed and implemented an effective hazard communication and response plan. A fire coordinator was designated to use the public address system to announce a fire and also pull the alarm box. But because the system was not shut down immediately after the first flash fire, he was among the injured and could not perform his duties.
The CSB report’s regulatory analysis highlights the need for a national general industry combustible dust standard which the agency has long recommended that OSHA promulgate, putting in on the CSB’s “Most Wanted” list in 2013, following years of urging action as dust explosions continued to occur in industry. The report, if adopted by the board, would reiterate the CSB’s original recommendation to OSHA, and also recommend OSHA broaden the industries it includes in its current National Emphasis Program on mitigating dust hazards, to include printing ink manufacturers.
Chairperson Moure-Eraso said, “Although OSHA’s investigation of this accident deemed it a combustible dust explosion, it did not issue any dust-related citations, doubtless hampered by the fact that there is no comprehensive combustible dust regulatory standard. In US Ink’s case—and thousands of other facilities with combustible dust—an OSHA standard would likely have required compliance with National Fire Protection Association codes that speak directly to such critical factors as dust containment and collection, hazard analysis, testing, ventilation, air flow, and fire suppression.”
The CSB report notes that the volume of air flow and the air velocity in the company’s dust collection system was significantly below industry recommendations—which, in the absence of a federal combustible dust regulation, are essentially voluntary. The report states the ductwork design did not comply in several respects with guidelines set by the American Conference of Governmental Industrial Hygienists (ACGIH) Industrial Ventilation Manual. Nor did the system’s design, the CSB said, comply with the voluntary requirements of NFPA 91, which states: “All ductwork shall be sized to provide the air volume and air velocity necessary to keep the duct interior clean and free of residual material.”
Chairperson Moure-Eraso said, “A national combustible dust standard would include requirements to conform to what are now largely voluntary industry guidelines and would go far in preventing these dust explosions.”
The report cites gaps in New Jersey’s regulatory system, noting the state’s Uniform Construction Code Act has adopted the International Building Code (which references NFPA dust standards) but has also exempted “manufacturing, production, and process equipment.” A proposed CSB recommendation to New Jersey’s Department of Community Affairs calls on the regulatory agency to revise the state’s administrative code to remove this exemption so that dust handling equipment would be designed to meet national fire code requirements. The state is also urged to implement training for local code officials as local jurisdictions enforce the code, and to promulgate a regulation that requires all occupancies handling hazardous materials to inform the local enforcement agency of any type of construction or installation of equipment at an industrial or manufacturing facility.
Chairperson Moure-Eraso said, “Events leading to this accident began even before the earliest planning stages, when the company failed to properly oversee the design, construction, and testing of a potentially hazardous system. The victims have suffered the consequences. We hope our recommendations are adopted so that these terrifying industrial dust explosion accidents will stop.”
California to Revise Proposition 65 Warnings
Proposition 65 requires that persons in the course of doing business give a clear and reasonable warning to individuals before knowingly and intentionally exposing them to a chemical listed as known to cause cancer or reproductive toxicity. California’s Office of Environmental Health Hazard Assessment (OEHHA) maintains the list of chemicals known to the state to cause cancer or reproductive toxicity
Existing regulations (Title 27, Cal. Code of Regs., section 25601et seq.) establish general criteria for providing “clear and reasonable” warnings. These regulations also provide safe harbor, non-mandatory guidance on general message content and warning methods for providing consumer product, occupational, and environmental exposure warnings. The new regulations proposed for adoption into Article 6, retain the safe harbor concept by giving a business the opportunity to use warning methods and content that OEHHA has deemed “clear and reasonable,” or a business may use any other warning method or content that is clear and reasonable under the Act.
Under the existing regulations, a warning is “clear” if it clearly communicates that the chemical in question is known to the State of California to cause cancer, birth defects, or other reproductive harm. It is “reasonable” if the method employed to transmit the message is reasonably calculated to make the warning message available to the individual prior to exposure. However, the existing safe harbor warnings lack the specificity necessary to ensure that the public receives useful information about potential exposures. Further, the current regulations were adopted over 25 years ago and communication technology has progressed significantly during that time. It is therefore necessary to update the regulations to take advantage of current and future approaches to providing important health-related information to the public.
OEHHA is proposing to repeal the current Article 6 regulations and adopt new regulations into Article 6. The proposal would, among other things, establish a new, mandatory regulation addressing the relative responsibility of product manufacturers and others in the chain of distribution, versus the product retailer. It also contains the definitions relevant to Article 6. The proposal provides guidance on methods and content for safe harbor warnings that will provide more detailed information for the public, including a clear statement that a person “can be exposed” to a listed chemical, the names of certain chemicals, and a link to a website maintained by OEHHA containing supplemental information.
. Businesses would continue to be assured that compliance with the regulations will help them avoid litigation because the content and methods provided in the regulation are deemed “clear and reasonable” for purposes of complying with the Act.
Contractors Fined $110,670 for Exposing Workers to Potentially Fatal Falls
OSHA inspectors visited the work site on July 11, 2014, in response to a complaint about fall hazards there.
"Falls are the number one killer in construction work. When fall protection is absent or deficient, as it was here, employees may be only moments away from a deadly or disabling plunge that could kill them or end their careers," said Mary Hoye, OSHA's area director in Springfield.
The project's general contractor, James J. Welch & Co., Inc., of Salem, was cited for the majority of the violations. OSHA found several fall hazards; no fall protection for employees working on the roof; unguarded floor holes; insufficient anchorage for fall protection; and employees untrained to recognize fall hazards. Because of these conditions, Welch was cited for one willful, one repeat and three serious violations of workplace safety standards, with $93,170 in proposed fines.
This is not the first time OSHA investigated this work site for safety violations. In July 2014, OSHA cited Connecticut-based abrasive blasting contractor Maher Industries, doing business as A Fast Blast, for lead, silica and respirator violations and proposed $47,600 in fines. The company is currently contesting its citations and fines.
"The sizable penalties reflect not only the danger of the fall hazards involved, but also the employer's knowledge of the hazards and its deliberate failure to safeguard its employees," said Hoye.
Heating, ventilation, and air conditioning contractor Atlantis Comfort Systems Corp., of Smithfield, Rhode Island, was cited for two serious violations, with $7,000 in fines, for failure to ensure the use of fall protection and failure to document fall protection training.
Masonry subcontractor Jean Beauthier, doing business as All Custom Masonry, of Rutland, was cited for two serious violations, with $5,600 in fines, for failure to provide fall protection for employees working on a scaffold and for using a scaffold that was not fully planked.
Finally, window contractor J&R Glass Service, of Fitchburg, was cited for one serious violation, with a fine of $4,900, for not protecting an employee from possible falls through a wall opening. A serious violation occurs when there is substantial probability that death or serious physical harm could result from a hazard about which the employer knew or should have known.
A willful violation is one committed with intentional, knowing or voluntary disregard for the law's requirements, or with plain indifference to worker safety and health. A repeat violation exists when an employer has been cited previously for the same or a similar violation of a standard, regulation, rule, or order at any other facility in federal enforcement states within the last five years.
The page offers fact sheets, posters, and videos that vividly illustrate various fall hazards and appropriate preventive measures.
Two Companies Fined Almost $200,000 for Electrocution Fatalities
During the same week of July 2014, two of California’s young workers were killed and one seriously injured in separate accidents involving contact with high-voltage electric lines in Mission Viejo and Los Angeles. Cal/OSHA has cited Five Star Plastering and Winlup Painting, Inc., a total of $194,685 for safety violations that contributed to those accidents. In both cases, employers failed to properly train and safeguard employees from the hazards of energized overhead power lines.
“All worksites in California are required to have a thorough work safety plan in place precisely to identify and avoid these types of violent and preventable accidents” said Christine Baker, Director of the Department of Industrial Relations (DIR). Cal/OSHA, formally known as the Division of Occupational Safety and Health, is a division of DIR.
Two 23-year-old employees of Five Star Plastering had been employed as scaffold erectors for three weeks when the accident occurred at Mission Viejo High School. As part of a three-man crew, they were assigned to erect a multi-stage metal scaffold on the football field. Daniel Pohl was working on the top level when his co-worker, Joshua Shetley, looked up from the ground and noticed that Pohl had fallen unconscious. Shetley climbed up to revive Pohl, but was thrown from the 20-foot scaffold after coming in contact with the 12,000 volt power lines. Pohl was pronounced dead at the scene, and Shetley was transported to Mission Hospital where he was kept for two weeks due to serious injuries.
Cal/OSHA determined that Five Star Plastering, based in Laguna Hills, failed to provide its workers with any safety training and also neglected to identify the electrical hazard. Citations for six violations were issued, with a total of $164,275 in proposed penalties. Violations included one in the most severe category, willful-serious, for allowing work to be performed in proximity of energized high voltage lines. Other safety violations were related to the lack of overhead protection and helmets for workers exposed to electrical lines, and for failure to complete safety measures prior to erection of the scaffold.
“Employers need to be especially vigilant to ensure that workers with little or no experience can recognize and avoid potential problems. Workers who are new on the job are often less prepared to recognize deadly hazards like what happened in this incident,” said Cal/OSHA Chief Juliann Sum.
At a job site in Los Angeles, Erick Ceron-Alegria, a 26-year-old employee of Winlup Painting, was elevated on a boom lift in order to paint balcony railings. The lift was placed closer than the 11-foot required minimum clearance of a 66,000 volt transmission line and made contact, electrocuting the worker. Cal/OSHA found that Winlup Painting (DBA Certapro Painters), based in Santa Monica, did not properly train employees in safe operation of boom lifts, nor did it adequately identify the hazards of operating an aerial device near high-voltage lines. Winlup was cited $30,410 in proposed penalties for four violations including two serious accident-related violations.
Cal/OSHA issues citations for serious workplace safety violations when there is a realistic possibility that conditions could result in death or serious physical harm, and willful violations where evidence shows that the employer committed an intentional and knowing violation.
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