Chemicals used in the workplace and the soup we enjoy at home share in a common problem. It comes down to what I call the soup theory.
Nearly everyone loves soup, as a child of the 70’s, canned soup was the ideal comfort food on a cold winter day. Occasionally when reaching into the back of the cupboard to grab the last can, we were surprised that it had separated into layers or simply had gone rancid. Ok, its grilled cheese instead of soup today!
It wasn’t until a high school food drive that I discovered my mom’s deviant behaviour. Several cans of soup located in the back of the cupboard had distinctly out of date labels. In fact, one of the products in the cabinet hadn't been available for several years. I then sorted through all the canned food goods, finding that the best before date aged the deeper I went into the cupboard for almost every product. When I confronted my mother on her inventory habits, she stated, that she would just place the new cans to the front of the designated storage location and push the existing cans back. It made sense, yet smacked of complacency and a lack of understanding in regards to food safety.
As an EHS professional, I routinely identify this same behaviour as part of audits or other programs, where the presence of “aged” chemical reagents is found hidden in the back of the chemical storage cabinets never to be used again or used past their expiration date. In fact, I have on multiple occasions discovered chemicals dating back as much as 20+ years. In some cases, the chemicals have become unstable and present dangers. In other instances, the chemical bottle has been used, and the contents have lost either potency, degraded such that their use in a process may not ensure a high-quality standard, or have merely evaporated, and all that remains is an empty bottle. Good luck getting a current MSDS from the chemical supplier who went out of business in the 90’s, not to mention reading the faded label, or dealing with those crystal structures in that bottle of picric acid.
In truth quality control experts, and chemical manufacturers do not stipulate an expiry date for a chemical unless its chemical and physical properties dictate a limited shelf life. Some chemicals form salts or other precipitates over time, like diethyl ether. Diethyl ether and similar chemicals can form dangerous peroxides over the course of years that can explode on contact if disturbed. These chemicals should be safely disposed of before they cause an explosion or other accident.
For most chemicals, there is no defined shelf life or disposal date. The longer the bottle has been sitting around, and how often it is opened may, at the very least, present a quality control issue, if not a health and safety one. Chemicals identified as being older than five years should be analyzed by a lab to validate their ability to perform to your specifications. ISO standards would dictate that a new certificate of analysis be provided.
The longer the bottle has been sitting around, and how often it is opened may, at the very least, present a quality control issue, if not a health and safety one.
If there’s no expiration or retest date anywhere on the bottle, then things get more complicated, and the line between safe and dangerously old becomes less clear-cut. Solid chemicals generally have a pass until they have been in inventory for five years under recommended and ideal storage conditions. Under less than ideal conditions, such as a bottle's seal having been broken, or if the chemical has been transferred to a different container, the chemical shelf life will be affected negatively. Refrigerated liquid chemicals may last quite a bit less time than solids, with recommended expiration dates of as little as 12 to 18 months.
A better approach to managing the age of chemicals in the workplace is to start by only procuring what you need within a shorter time, and limiting the volumes. Here are some tips to best manage your soup cupboard:
- Always rotate your inventory of each chemical such that the oldest container is at the front of the cabinet and will, therefore, be used first. Use the open container first, and avoid having multiple open containers.
- Only purchase what you need and will use in a pre-determined period. If you use a material every day, you will replenish your supply frequently. However, if you only use a product infrequently in small volumes, look into purchasing smaller containers at regular intervals to prevent a chemical from becoming unstable or unusable.
- Annually audit your storage areas, cabinets and under the sink to ensure older chemicals, and particularly those that can become dangerous over time are identified for disposal.
- Track your chemical usage, have you stopped using a specific chemical or has the volume required changed that would allow you to change either your purchasing quantities and or the size of bottle/container.
- If you find old chemicals, damaged containers, or materials you do not use anymore, look internally to see if any other laboratories can or would use the remaining volumes. Where the chemical cannot be used, have it disposed of following hazardous waste requirements (TDG).
- Be prepared for surprises, such as finding incompatible materials stored together, it happens. In these situations, immediate action correct should be taken to eliminate the hazards.
When in doubt have a qualified chemical storage specialist assist you in setting up your chemical handling and storage program to ensure worker safety, minimize waste, classify and dispose of hazardous wastes, and streamline your chemical inventory process.
When in doubt have a qualified chemical storage specialist assist you in setting up your chemical handling and storage program to ensure worker safety, minimize waste, classify and dispose of hazardous wastes, and streamline your chemical inventory process. Don't allow your mother's past mistakes to haunt you in the workplace. Make sure that your chemicals don't fall victim to the "Soup Theory." Regularly rotate chemicals and monitor expiry dates for safety and effectiveness. There is nothing wrong with grilled cheese, but when you are anticipating soup…do not allow yourself to be disappointed.