November 18, 2011 | General

Worker Safety In Confined Spaces

BioCycle November 2011, Vol. 52, No. 11, p. 15
Recent tragedy at California composting facility underscores need to establish and follow stringent safety protocols.
Dan Sullivan

A recent tragedy at a Lamont, California, composting facility at which two workers died, apparently from exposure to hydrogen sulfide and carbon dioxide gases, underscores the need for proper safety protocols and training when entering confined spaces. U.S Department of Labor and Cal-OSHA continue to investigate the accident that killed two brothers, ages 16 and 22, at Community Recycling and Resource Company in Arvin. Newspaper accounts stated the victims were overcome by fumes 6 to 8 feet down a shaft in a cement drainage tunnel. A third worker overtaken by fumes at the opening of the tunnel was reportedly treated and released.
According to a recent article by Nellie Brown, Director of Workplace Health and Safety Programs for Cornell University’s School of Industrial and Labor Relations, a review of fatalities in livestock manure storage and handling facilities between 1975 and 2004 found that 22 percent of 77 deaths occurred when would-be rescuers were overcome themselves. The initial victims entering confined spaces to perform maintenance or repair accounted for 34 percent of the deaths.
Brown’s two-part article – which ran in the February and March 2011 issues of Firework, the newsletter for the International Association of Women in Fire & Emergency Services – defines a “confined space” as a space that has limited or restricted means of entry or exit, is large enough for a person to enter and is not designed for occupancy. While Occupational Safety and Health Administration (OSHA) standards (29 CFR 1910.146) regulate work in confined spaces, writes Brown, production agriculture is exempt (although it is highly recommended the procedures are still followed). Commercial composting facilities not connected to agricultural production are required to follow OSHA protocols.
As Brown points out, both composting and anaerobic digestion projects are on the rise as zero waste and renewable energy goals take center stage. While that’s good news, says Linda Vanderhoek, an environmental protection officer with British Columbia’s Ministry of Environment, adequate safety training should accompany that growth. Vanderhoek was involved with regulating and was interviewed during an investigation into mushroom substrate manufacturing on a farm in Langley, British Columbia, in which five victims were overcome by hydrogen sulfide gas inside a poorly ventilated pump shed. “There’s great excitement in B.C., people scrambling to get compost operations in place and starting curbside collection programs,” she says. “But people wanting to compost should be aware that it can be dangerous if not done properly.”
In Langley, according to Vanderhoek, the mushroom substrate composter had indoor windrows aerated from the bottom with a leachate collection system piped underground to a collection pond. When the underground piping became plugged, an initial worker went out to unplug it and was overcome by toxic gases, setting the stage for the tragic chain of events that followed. Three men died while two others were left severely brain damaged. “Five people’s lives were destroyed,” says Vanderhoek. “They were in an area where the pipe came into a leachate collection pond and the operator had built a little hut over the area where they were trying to unclog pipes. It might have been an enclosed space circumstance that led to the deaths and injuries.”
Results of a government inquiry into the Langley tragedy will not be released until after sentencing in the case, which is scheduled for November 25, 2011. The owners of the mushroom farm pled guilty to 10 worker safety violations including failure to have an occupational health and safety program in place, failing to educate workers about safety, failure to properly supervise workers and failure to make workers aware of confined space hazards.
Vanderhoek underscores what news services reported about the Langely incident in the three years leading up to the September 2011 sentencing hearing: The defendants, owners of A-1 Mushroom Substratum Ltd. and H.V. Truong Ltd., had no idea that these potential hazards existed at their facility. Neither, apparently, did key regulatory authorities including WorkSafeBC, the Workers’ Compensation Board of British Columbia. “It is true that [the hazard] wasn’t known widely by the industry and the regulatory bodies at the time,” WorkSafeBC spokesperson Donna Freeman told reporters outside the sentencing courtroom this September. “The incident was unique, and we have learned a lot since.”

According to Brown, the best solution to the confined space issue is prevention through design. That is, tanks and other potential hazard areas where dangerous and potentially lethal gases could accumulate could be designed with no human entry possible. Another solution could be employment of cables and winches to remove pumps and agitators from tanks and pits so that they can be serviced without requiring entry.
While proper training and equipment are paramount when entering confined spaces, Brown says workers lacking both of these put themselves in harm’s way for the following reasons:

  • They are unaware of a hazard.
  • They have performed the same task before without incident.
  • They assume they can hold their breath, perform the task quickly and exit without a problem.
  • They assume hazardous gases can be seen or smelled, thus alerting them of any potential danger.
  • They are attempting to rescue a distressed coworker.

Hydrogen sulfide in particular paralyzes one’s sense of smell. Other gases associated with organic decomposition, such as methane and carbon dioxide, can fill a confined space so completely that regular air is pushed out, explains Brown, thus creating an atmosphere that is too oxygen deficient to support life. “Oxygen deficiency especially targets brain cells, which have ten times the oxygen needs of other types of cells in the body. Normal air is 21 percent oxygen, and 19.5 percent is the minimum safe level. As the level of oxygen drops below 19.5 percent, judgment and coordination become impaired — that is, people can act goofy and have no sense of danger at all. Unconsciousness occurs at 8 to 10 percent, and, in an atmosphere of 4 to 6 percent, oxygen deficiency is rapidly fatal — too fast for the fire department to arrive in time for rescue. Sometimes the victim‘s heart is still beating, but the brain is dead.”
“The whole point of OSHA is to eliminate safety hazards in all aspects of your operation, from the physical plant and equipment to the atmospheric,” says Philip McCarthy, president and manager of the Marlborough, Massachusetts, composting facility operated by WeCare Environmental. Key components of an OSHA program include identifying and mitigating existing and potential hazards as well as providing workers with proper equipment and training, he adds. “You put in safety standards, and you keep people away from tasks and areas where they may not be properly trained. You identify hazards, and you engineer out solutions to any issues. If you can’t engineer out solutions, then you go to your [safety] programs.”
The federal OSHA program is administered through each state, explains McCarthy, and each runs a cooperative consultation program. “They come to your facility, do a top-to-bottom assessment and analysis and the client receives a report. It does not incur any fines, but you are required to fix any hazards they find. That is the program that the WeCare Marlborough facility undertook the second half of 2006 throughout 2007 and became OSHA SHARP certified in 2008. It has included multiple inspections of the physical plant.” Refresher safety, hazard and rescue training are also part of the ongoing program, he adds, and the company has been recertified through 2012.
OSHA provides some written programs that facilities need to customize into a site-specific safety document. “Certain aspects of [the programs] will be used as training review and education so you can keep the subject of safety on top of everybody’s mind,” continues McCarthy. “It’s really true that as soon as you take your guard down that’s when people get hurt. If you’ve taken the time to engineer out potential hazards and purchase the right equipment to keep your employees safe, and if you have classes so they know how to use the equipment and react to certain situations, then people think clearly and everybody thinks ‘safety.'”
The goal of any confined space entry program is to take a situation or location and turn it from a permit-required confined space situation to a nonpermit required confined space situation, he adds. “You do that by eliminating the existing as well as the potential hazards, if possible.” OSHA’s Lockout/Tagout standards address the practices and procedures for disabling machinery or equipment in order to prevent the release of “hazardous energy” while employees perform service and maintenance activities. Hazardous energy includes but is not limited to electrical, mechanical, hydraulic, pneumatic, chemical and thermal energy. Add a confined space situation, and the potential hazard is multiplied.
While designing to minimize confined spaces as much as possible is a good idea, their existence to some degree is inevitable, says Robert Spencer, an environmental planning consultant, who as a composting facility manager has written OSHA training documents for composting operations. “I’ve been through the design and construction of a number of plants,” says Spencer, who is also certified to teach confined space safety. “Composting facilities and their potential to generate hydrogen sulfide in confined spaces have much in common with the hundreds of thousands of wastewater treatment plants around the globe, and safety procedures are very well established in that industry.”
It is often not practical or cost-effective to design a facility to eliminate confined spaces since the existing topography of a site determines the extent of confined spaces related to drainage — from storm drains to sump pits for leachate. “It’s very expensive to elevate a site to keep such drainage facilities at grade or above ground, so they most often are below grade as confined spaces,” Spencer explains. In addition, with odor control technologies, from enclosed biofilters to scrubbers for pretreating air to duct work for facilitating the exchange of massive volumes of air, some level of confined spaces are going to be a reality at any facility, he says.
“The key to safely operating a composting facility with confined spaces is to first identify them, post the required signage at each confined space, provide training for employees who will be entering those confined spaces and implement the procedures each and every time a confined space is entered,” Spencer emphasizes. “These OSHA-required procedures should also be embodied and linked to the operations and maintenance procedures customized for each composting facility. In this way, tragic accidents can be prevented.”

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