Canadian Occupational Safety

22 Canadian Occupational Safety | www.cos-mag.com I n 2008, a research assistant working in a chemistry lab at the University of California, Los Angeles was transferring a liquid chemi- cal from its original bottle to another bottle. The chemical involved, tert-Butyllithium (or t-BuLi) is highly pyrophoric: it ignites on contact with air. She had put on goggles and gloves but, instead of a fire-resistant lab coat, was just wearing a synthetic-fibre sweatshirt. For the transfer, she had to insert the needle of a large plastic syringe into the bottle's seal to draw the liquid up. As she did so, the syringe came apart in her hands. The spilled liquid instantly ignited and set her sweatshirt on fire. Sheri Sangji, who was 23 years old, suffered second- and third-degree burns to almost half her body and died 18 days after the incident. Many workers require protection against both fire and chemical hazards. These hazards are pres- ent with many of the tasks performed in workplaces such as refineries, petrochemical plants and labora- tories. It has always been difficult to provide effective protection for workers who face these dual hazards because of the limitations of garment materials. Today, however, some newer fabrics coming onto the market combine increased chemical protection with fire resistance. Flame resistant and chemical protection (FR/ CP) garments can be divided into three levels and types of clothing, says Paul Bryce, vice-president and general manager of the chemical solutions strate- gic business unit at Cowansville, Que.-based Ansell Canada. In heavy industrial workplaces or fire and emergency services, there are re-usable materials that have added materials, such as Nomex, embedded into them. "If a firefighter is responding to a chemical spill and there happens to be a flashover (the ignition of exposed combustible material in an enclosed area), then these suits are tested to an extent that the flashover will not cause the suit to fail. In other words, the firefighter still has enough protection from the suit to get out of that environment and save their life," he says. "That's the pinnacle of pro- tection from a chemical. These suits are designed to protect against pretty much anything. And at that level of protection, they are also designed to deal with a flash-fire instance." The next level down is the liquid-protective suit, Bryce says. This also is a re-usable, chemical pro- tective garment that a worker wears over top of a thermal protective garment to provide splash-chem- ical protection. Finally, there are disposable suits. These are designed primarily to protect against a chemical, whether that is liquid or dust. Most of the disposable or limited-use garments on the market are essentially sacrificial, he says. They're meant to limit the spread of a fire. "In the event of a flashover incident, when the flame is removed, the garments are designed not to continue to burn, not to melt and not to drip and cause secondary issues. Indeed, it's the layer- ing system, the wearing of a Nomex or Proban, or another type of flame-retardant clothing underneath that protects the person. These outer chemical suits are just designed not to add fuel to the fire, so to speak," Bryce says. NEW TECHNOLOGIES When workers in refineries and petrochemical plants require protection against harmful chemicals, the usual practice has been to wear a chemical suit over a thermal protective garment. The thermal protective coverall is often made of Nomex (or other aramid) or a flame-retardant cotton and acts as a guard against flame, heat and flash fire. However, chemical suits are generally made from a blend of polymers, usually polypropylene and polyethylene, which are thermoplastics and flammable. Coming in contact with a flame or flash fire, the chemical suit will not only burn but also melt and drip burning plastic that will stick to clothing and skin. Wearing a chemical suit made of thermoplastic material greatly reduces the pro- tective quality of the thermal protective garment underneath. As a result, safety managers have often had to decide which hazard was a bigger concern: potential for flash fire or exposure to a dangerous chemical, says Randy Hillmer, Calgary-based national sales manager for Canada at Lakeland Industries. Very often, the person had to choose chemical protec- tion without the fire retardant because it was the most likely hazard. "The PPE choices did not match up with the requirements of the workers," he says. But in recent years, while protection from flash fires hasn't really changed much, the technology for chemical protection has advanced significantly, Hillmer adds. For example, 20 years ago, Lakeland sold a garment that was designed to protect against very light chemical splash. Fifteen years ago, it came out with a garment that was for light splash protec- tion from a fairly wide range of chemicals. Its newest garment provides a "fairly high level of chemical Advances in fabric technology are making better protective garments for workers who face both fire and chemical hazards By Linda Johnson

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