Do you have simultaneous operations, or SIMOPS, at your workplace? If so, you may want to make sure your procedures are up to snuff.
Why? Because poorly managed SIMOPS has contributed to several major hazardous material incidents in the past two decades.
SIMOPS was most recently cited by the U.S. Chemical Safety and Hazard Investigation Board (CSB) as a root cause of the fatal 2020 Wacker Polysilicon hydrogen chloride gas release.
However, simultaneous operations were also among the root causes of several other incidents in the U.S., including the:
fatal fire at the Evergreen Packaging Paper Mill in September 2020
ethylene release and fire in May 2018 at the Kuraray America, Inc. EVAL Plant that injured 23 people
On Nov. 8, 2008, Allied Terminals tank collapse led to two injuries and 200,000 gallons of liquid fertilizer released into the environment
BP America refinery explosion in March 2005 killed 15 and injured 180, and
Jan. 16, 2002, Georgia-Pacific Corp. hydrogen sulfide poisoning incident that killed two and injured eight.
What are simultaneous operations?
According to the American Institute of Chemical Engineers, SIMOPS is defined as “situations where two or more operations or activities occur close together in time and place.
“They may interfere or clash with each other and increase the risks of the activities or create new risks resulting in undesired events … with adverse impacts on … process safety. SIMOPs often involve work in the same area by multiple … workers whose work may overlap and/or interact.” While this definition is focused on process safety, SIMOPS concerns can be present outside of chemical manufacturing.
For example, if forklift operators have to change propane tanks or batteries in the same place where maintenance is welding, replacing an electrical outlet or doing some sort of task that makes sparks, you have SIMOPS. In this case, the maintenance department’s work, which is separate from the forklift operator’s, could pose a major risk as an ignition source for propane or hydrogen gas (which is present as a byproduct of electric forklift batteries).
With that in mind, safety professionals may have more SIMOPS to deal with in their facility than they may realize. Neither contractor group knew the other was in the area
The fatal 2020 Wacker Polysilicon hydrogen chloride release occurred while two different groups of contractors performed different tasks on the same elevated platform.
Wacker Polysilicon’s Charleston, Tennessee facility had contract companies Jake Marshall LLC, a general mechanical contractor, and Pen Gulf Inc., an industrial coating specialist, on-site to perform work on Nov. 13, 2020. Jake Marshall was hired to perform maintenance on a heat exchanger on the fifth floor of the outdoor platform. Pen Gulf was on site to apply insulation in the same area.
The platform had only one set of stairs for access. There were no other ways on or off. Both companies had previously been issued permits to work in the area by a Wacker permit authorizer.
Three Jake Marshall workers began setting up for their work on the platform at 8:10 a.m. before returning to ground level for further preparations. At 9:15 a.m., four Pen Gulf workers arrived on the platform and began preparing to do their work.
Sometime before 10 a.m., the Jake Marshall workers arrived back on the fifth floor of the platform and eventually made contact with the Pen Gulf workers. Neither group had known the other was going to be working on the platform at the same time.
Discrepancies in PPE levels The Pen Gulf workers, worried for their safety, noticed that the Jack Marshall workers were wearing chemical-resistant PPE, while they were wearing the minimum PPE required by Wacker:
flame-resistant clothing
steel-toe safety boots
hard hats
escape respirators
safety harnesses
safety glasses, and
gloves.
The Jake Marshall workers were wearing:
full-body chemical-resistant suits
rubber boots and gloves, and
full-face respirators with acid-gas cartridges, as required by Jake Marshall policy for workers involved in operations on pipes containing hazardous chemicals.
Since they weren’t planning on actually working with any chemicals, the Jack Marshall workers told the Pen Gulf workers they should be fine with the PPE they were wearing.
Excessive torque on the bolt leads to release
Just after 10 a.m., the Jack Marshall workers used a torque wrench on some bolts around the heat exchanger. They were missing information on how much torque to use, used excessive torque and cracked the heat exchanger, causing hydrogen chloride gas to release.
Within 15 seconds, a white gaseous hydrogen chloride cloud filled the area, preventing the workers from being able to see their surroundings.
Ripped chemical suit results in burns
As one of the Jack Marshall workers attempted to move away from the release, his chemical suit snagged and tore open, allowing the gas to enter his suit and cause chemical burns on his skin. He also bumped into equipment on the platform and knocked off his respirator.
Due to the breach of his PPE and the location of the release, the worker couldn’t escape to the single staircase on the opposite side of the platform.
He moved to the opposite side of the platform with his co-workers and Pen Gulf employees. The other Jake Marshall workers placed their injured co-worker into a nearby safety shower to protect him from the hydrogen chloride release.
1 dead, 2 injured in fall while attempting to escape
Three of the four Pen Gulf workers put on their escape respirators, but realized they’d have to walk through the gas cloud to get to the platform’s sole exit. They began climbing down piping on the side of the platform to escape the release. While attempting their escape, all three workers fell 70 feet to the ground below. One worker was killed while the other two sustained serious injuries. Meanwhile, back on the fifth floor, the remaining Pen Gulf worker received assistance putting on her escape respirator from a Jake Marshall employee, who also attempted to shield her from the release since he was wearing chemical-resistant PPE.
The release continued for three minutes until all of the hydrogen chloride gas had escaped from the system. Once the release stopped, the three Jake Marshall workers and one Pen Gulf worker used the staircase to evacuate the area and reach the ground.
The incident resulted in one death, three injuries, and $214,000 in property damage.
General lack of industry, and regulatory guidance on SIMOPs CSB investigators found that poor SIMOPs were among the root causes of this incident, along with written procedures governing torquing bolts, control of hazardous energy procedures, and means of egress issues.
The CSB investigation report states that when the incident occurred, four workers from a separate company were performing unrelated pipe insulation work, as permitted by Wacker, and were present on the fifth-floor platform near the other work crew.
Wacker didn’t have a policy or procedure for evaluating SIMOPs, which is a situation in which two or more operations occur together at the same time and place.
Further, the CSB found that there’s a general lack of industry and regulatory guidance on SIMOPs available to companies such as Wacker.
As a result, Wacker didn’t evaluate the risks associated with the simultaneous work tasks, which led to the contract workers who weren’t involved in the torquing task being unnecessarily exposed to the hydrogen chloride release.
The CSB has since issued recommendations to federal OSHA and state agencies to “require the coordination of simultaneous operations involving multiple work groups, including contractors” and to “create safety products to provide guidance on simultaneous operations.”
What can employers, and safety professionals do to address SIMOPs? A key lesson the CSB specifically pointed out in its report is that employers should always consider how SIMOPs could impact a given operation, whether by influencing a hazard or affecting the risk of the operation.
SIMOPs “should be identified and controlled via a hazard assessment prior to commencing a given operation or task,” according to the CSB.
An established system to manage work permits can also aid in identifying risks associated with SIMOPs before they occur. Such a system must:
be able to document the specific task to be executed
readily coordinate the issued permits, and
identify scenarios of potential interaction between permitted work groups.
To identify potential hazardous interactions in SIMOPs, the CSB recommended:
evaluation and implementation of necessary safeguards to allow for safe SIMOPs
coordination, including shared communication methods, between the groups participating in SIMOPs, and
inclusion of emergency response personnel or services in the planning and coordination of the SIMOPs.
Source: https://rb.gy/5ei02
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