Canadian Occupational Safety

20 Canadian Occupational Safety www.cos-mag.com matter of concentration: In low concentration they can be an irri- tant to the skin or eyes, but in a stronger concentration they cause enough damage to the skin or eyes that we end up with a scar." Corrosive materials are pres- ent in almost every workplace, and everyone who works with corrosives must be aware of their hazards and how to work safely with them. "You're never going to find an industrial site that doesn't have a corrosive in it somewhere," says Darcy Carriveau, Responsible Care co-ordinator at Vancouver- based Methanex. "Even lubricants are significant corrosives often because of their cleaning properties." Most corrosives are either acids or bases. Common acids include hydrochloric acid, sulfuric acid, nitric acid, chromic acid, acetic acid and hydrofluoric acid. Common bases are ammonium hydroxide, potas- sium hydroxide (caustic potash) and sodium hydroxide (caustic soda), according to the Canadian Centre for Occupational Health and Safety. For occupational health and safety professionals, Fox adds, another con- cern is whether a chemical will corrode other materials, particularly metal. "A material that is subject to a cor- rosive and fails during operation can present a safety hazard, not just a hazard to health," he says. Take sTock The first step to working safely with corrosive chemicals is conducting an inventory of all such materials on- site, says Ilma Bhunnoo, occupational hygiene specialist with Workplace Safety and Prevention Services (WSPS) in Mississauga, Ont. The inventory should identify: • chemical types • physical state (solid or liquid) • toxicity • material temperature • storage location. The risk assessment should also examine handling processes, she says. This covers such information as amounts used, whether exposure is continuous or intermittent and whether workers are exposed through contact, inhalation or ingestion. It's also important to evaluate both long- and short-term exposures. A worker may, for example, be required to stand beside an electroplat- ing tank filled with a diluted acid and be performing a dipping process for an entire shift. Here, she says, you must consider the eight-hour exposure. "Another worker, however, may have to pour the concentrated solu- tion into a mixture. It may take only 15 minutes to do, but exposure during those 15 minutes may be very high," says Bhunnoo. In assessing possible consequences of an incident, employers should con- sider corrosives from three perspectives: health effects (which range from first- aid injuries to critical injury or fatality); chemical reactivity (some chemicals are incompatible) and flammability (some cause explosions or fires). To implement hazard controls, sub- stitution is the obvious first step, says Fox. However, where highly corrosive By Linda Johnson A t Calgary-based Canexus, which manufactures cor- rosive chemicals including sodium hydroxide and hydrochloric acid, no one gets into the plant without proper per- sonal protective equipment (PPE). "That's step 1. Corrosives, espe- cially sodium hydroxide, can burn the skin," says Jennifer Lewis, man- ager of quality and Responsible Care, an industry wide initiative to promote environmental, health and safety per- formance. "But it can be very subtle, as well, because it feels like soap." Corrosives are materials that can attack and chemically destroy exposed body tissues. They begin to cause damage as soon as they touch the skin, eyes, respiratory tract and diges- tive tract. "It's where there has been corrosion of the tissue, not just irritation. Cor- rosion kills living cells," says Warren Fox, an instructor in the occupational health and safety program at the Brit- ish Columbia Institute of Technology (BCIT) in Burnaby, B.C. "With many of the chemicals we work with, it's a COMMOTION corrosive chemicals can cause irreversible damage to skin, eyes, respiratory tract

• Cover