Excerpt taken from John K. Borchardt’s article, Proper Disposal or Reuse of Old Laboratory Chemicals, Lab Manager Magazine May 2011 issue.

Having periodic cleanup days during which old chemical samples and unused/nonfunctional equipment is collected and disposed of can be a useful way of putting labs in clean, tidy and safe operating condition. These cleanup days are most effective in achieving these goals if lab managers insist that all routine work stop for the day to focus on cleanup.

Sometimes only an individual laboratory rather than the entire facility needs to have a laboratory cleanup day. This situation can arise if a laboratory is being relocated from one location to another either within the facility or from one facility to another. Alternatively, the termination of a project or its relocation from one laboratory to another may be facilitated by a lab cleanup day.

If an individual laboratory rather than the entire facility is cleaning up and disposing of old chemicals, have the appropriate lab staff members advertise their lack of availability to coworkers before this process begins. Interruptions can greatly reduce the efficiency of the cleanup process and increase the time required for it.

Once old chemical samples are identified and selected for disposal, proper procedures must be followed. Lab managers can have samples packed properly by lab personnel for pickup and disposal by a qualified chemical disposal firm. Some disposal firms will perform all the work themselves. This approach may be more appropriate for large laboratories.

While any chemical to be discarded is chemical waste, hazardous chemical waste is defined by the Environmental Protection Agency (EPA) or a relevant state authority as waste that presents a danger to human health and/or the environment. The EPA defines four key properties that determine whether a chemical is hazardous waste: ignitability, corrosivity, reactivity and toxicity.

Potentially hazardous chemicals must be disposed of in accordance with federal and state regulations and procedures. EPA regulations are summarized at www.epa.gov/epaoswer/osw/conserve/clusters/schools/index.htm.

While state requirements vary somewhat by locality, the basics remain the same. However, it is best to consult with your relevant state agency or the EPA to determine whether particular chemicals are defined as hazardous and what the requirements are for storage and disposal. These requirements should be defined on the chemical’s MSDS. However, if the chemical was purchased some time ago, the available MSDS sheet may be out of date and you should consult the current version of the MSDS.

Many labs use one or more large containers labeled “chemical waste” for solvents and other chemical wastes. Extreme care must be used in combining chemicals in such containers, as some chemicals may be incompatible. For example, addition of a strong oxidizing agent may result in oxidizing another chemical in the container and leading to heat evolution and an explosion or fire.

Because of the dangers of such chemical incompatibilities and the hazards of chemical spills occurring in a busy work area, chemical waste containers should be stored away from normal work areas and away from sinks and floor drains. Every addition of a chemical waste to a storage container should be noted in a permanent record such as an online file or a laboratory notebook.

Do not completely fill waste containers, particularly waste storage bottles. While the amount of empty headspace at the top of the container can vary with the size of the container, it is usually best to allow about 20 percent vacant headspace at the top of the container for possible vapor formation or liquid expansion due to heat evolution.

To remove chemical wastes from your laboratory site, contact professional, licensed hazardous waste haulers and transporters. Trained personnel from these firms will package waste chemicals properly for transport and disposal.