Exposure to hazardous waste can cause a host of harmful effects to humans and the environment.
Hazardous waste can harm wildlife, seep through soil, mix with groundwater, and eventually get consumed.
Preventing these outcomes starts in the lab. It starts with how you clean your empty chemical containers, how you dump the hazardous waste, and how you dispose of your containers.
We'll take a look at several key concerns:
- Which chemicals are hazardous
- Which chemicals are prohibited from drain disposal
- How to clean a chemical container
- How to know if a container is suitably clean
- How to dispose of empty chemical containers
Let’s get started.
Which Chemicals Are Hazardous?
It can be tough to know whether a chemical is hazardous or not.
Labels can be misread or poorly designed, and sometimes, the universal sign for hazardous waste is missing – among other complications.
Thankfully, the EPA has put together a master list of “P-Listed” wastes. These chemicals are deemed “acutely hazardous,” and there are almost 200 of them.
Whenever you are unsure, refer to this list. It’s in alphabetical order so the chemicals are easy to find.
Which Chemicals are Prohibited from Drain Disposal?
UC Berkley put together a list of chemicals that cannot be washed down the drain:
- All alkanes and water-insoluble hydrocarbons, including: Mineral spirits, Stoddard solvent paint stripper (e.g., Jasco), Petroleum hydrocarbons, Naptha, and solvent-based adhesives.
- All chlorinated and brominated hydrocarbons.
- Chlorinated solvents, including: Methylene chloride (dichloromethane), Tetrachloroethylene (perchloroethylene), Trichloroethane, and Trichloroethylene.
- Chlorofluorocarbons (freons)
- Concentrated acids and bases (pH 10)
Refer to this list before dumping any chemicals. If you have these types of chemicals and need to dispose of them, contact your local hazardous waste transportation company.
How to Clean a Chemical Container
Once chemical containers are cleaned, they are no longer determined hazardous waste.
However, they do need to be meticulously cleaned to remove all traces of the chemical before being disposed of.
To clean a chemical container, follow this process from the University of California at San Diego:
- Check the list of Known Hazardous and Extremely Hazardous Wastes and determine if the material is listed as "extremely hazardous waste."
- If the material is listed as extremely hazardous waste, the container must be collected by Environment, Health and Safety (EH&S), if your company or university has one and disposed of as hazardous waste by a licensed hazardous waste disposal company.
- DO NOT rinse the container if it is deemed “extremely hazardous.”
- If it is not extremely hazardous, clean the container by triple rinsing it with water or another solvent. Then, air-dry it before disposal.
For volatile organic solvents not on the list of acutely hazardous waste (like acetone, ethanol, ethyl acetate, ethyl ether, hexane, methanol, methylene chloride, petroleum ether, toluene, xylene, etc.), the emptied container can be air-dried in a ventilated area without triple rinsing (Princeton).
How to Know if Your Chemical Container is Suitably Clean
UC San Diego provides a good outline that will tell you if your container is clean enough to be disposed.
For liquid hazardous material containers:
- No liquid should drain when the container is tilted in any direction.
- No more liquid can physically be removed.
- The walls are free from any chemical encrusted on them (a thin layer of dried material may be accepted).
For solid hazardous material containers:
- The interior surface must be completely scraped clean, with no residual chemical.
For aerosol containers:
- The contents and pressure must be completed dispensed.
- The sprayer is working and in place.
For gas cylinders:
- Contact your company’s EH&S Environmental Management, or a licensed hazardous waste disposal company for instructions.
Finally, if it’s impossible for you to clean the container, it must be collected by your facilities EH&S department or contact a hazardous waste disposal company.
How to Dispose of Specific Chemical Containers
According to UC San Diego, containers should be disposed of according to their size.
Greater than 5 gallons (glass, plastic, or metal):
- The container must be dated and collected by Environment, Health & Safety (EH&S) within 1 year.
- Attach a completed hazardous waste tag and request a hazardous waste collection.
Equal to 5 gallons, metal only (for 5-gallon glass or plastic containers, go to the next step):
- Keep the container closed and cross out labels. (Important: Make sure you can still read what chemical was in it, so don’t completely destroy the label.)
- Write the date on the outside of the container.
- Look up where to dispose empty chemical containers in your area.
Less than or equal to 5 gallons (glass, plastic, or metal):
- Cross out labels on the container. (Once again, don’t completely destroy the original product label.)
- Dispose of the container in the regular trash.
Chemical containers, and the chemicals within them, need to be disposed of appropriately.
You know which chemicals are hazardous, which chemicals you cannot wash down the drain, how to clean a chemical container, how to know if it is cleaned properly, and how to dispose of your empty chemical containers.
Follow this process and you will help reduce the harmful effects hazardous waste can cause to both humans and the environment.