When you think of poisons, you might imagine arsenic in an unpopular king’s food, or a cyanide pill carried by a spy in case of capture. But what about soy sauce?
In 2011, a university student drank a quart of soy sauce while joining a fraternity, and spent three days in a coma as a result. Normally, soy sauce wouldn’t be considered a poison, but it normally isn’t consumed by the quart. This is where an important idea comes in: “The dose makes the poison.” A small amount of a substance may not cause any health problems, while a large dose of the same substance can. This holds true for a wide range of materials — from cyanide to soy sauce.
Types of Exposures
There are two major types of poison exposure: “acute” and “chronic.” A single large dose (like that soy sauce, or the cyanide pill) is considered an acute exposure. These are often the results of major accidents or intentional actions, and are typically obvious. Chronic exposures, on the other hand, are continuous or repeated exposures that happen over a long period of time. Each individual dose may be very small, or even unnoticed. Chronic exposures are less dramatic, but depending on the substance, they may be much more dangerous.
With chronic exposure, some materials will build up in the body over time. In this process, called “bioaccumulation,” the substance enters the body faster than the body can get rid of it. The result is a very large effective dose, even though each exposure was relatively small.
Mercury bioaccumulation, for example, used to be common among hat factory workers, who used mercury compounds to stiffen felt. Over time, the mercury would build up and cause neurological damage, the origin of the phrase “mad as a hatter.” As the industry became more aware of the hazards of chronic mercury exposure, the practices changed, and mercury poisoning became rare.
Mercury isn’t used in making hats anymore; it’s been replaced with safer and cheaper materials. When dangerous chemicals must be used, though, the best approach is to keep the dosage as low as possible. Many materials, even in hazardous industries, have a known safe exposure level — a dosage at which no significant negative effects are observed. If that university student had stopped at an ordinary serving of soy sauce, for instance, he wouldn’t have made headlines; the problem started when he took an unusually large dose.
To keep workplace exposures in the safe dosage range, OSHA maintains a list of a Permissible Exposure Limits (PELs) for certain materials. Other organizations also study materials that could be dangerous, and offer Occupational Exposure Limits (OELs). Because the organizations that create OELs generally have no legal authority, these limits are left as voluntary standards and industrial best practices. Even so, OSHA will often compare an inspected facility’s practices to common practices elsewhere in the industry, including these voluntary standards.
Managing Poisons for Safety
The average worker isn’t likely to drink a quart of soy sauce at work, but he might not wear the right protective equipment to deal with chemicals if he’s not aware that they pose a hazard. To properly manage poisons and poison exposure, people need to know what a given material is, and what specific hazards it can present.
This is best achieved with labels. The international GHS chemical labeling system uses bold and easily-recognized symbols to mark the specific hazards associated with a chemical, and to make those hazards clear at the place where the chemical is actually in use. OSHA’s Hazard Communication 2012 system (HazCom 2012) is based on GHS, and shares that approach.
For these labels, each symbol is printed in black, inside a red diamond shape. The classic skull-and-crossbones symbol identifies the most dangerous poisons — those that can cause death in a single exposure, with a relatively small dosage. The “health hazard” symbol, a silhouette of a person with a six-pointed burst inside, is used to mark slightly less dangerous materials. These poisons only cause serious health concerns for specific organs, or are only dangerous through repeated exposures over time. Finally, a simple exclamation point is used for poisons that require large doses to be dangerous, or that have only minor or temporary effects.
Also on the label will be specific details about the hazard, as well as precautionary steps that should be taken to prevent or respond to an accidental exposure. These details will be listed on the material’s Safety Data Sheet (SDS). The required format for the SDS changed with the introduction of the HazCom 2012 system, so it is important to keep documents up-to-date. Graphic Products offers a free guide to the GHS and HazCom 2012 systems, which you can request at 1.800.788.5572 or through our website. Using these labels to inform employees will help to protect their lives, as well as your bottom line, and will help keep your facility as safe as possible.