expired lab chemicals

Expired Lab Chemicals: What Are Your Options?

In this post, I want to highlight an article on “expired” lab chemicals that recently popped into my LinkedIn feed.

The article is titled, How to Handle Lab Reagents After Their Expiration Date and was originally published on labmanager.com. It was written by a postdoctoral fellow and shared on LinkedIn by a VP in the biotech industry.

As a former scientist, I opened the article expecting to find a justification for keeping chemicals beyond their “expiration” date. My safety professional side wondered whether it would call for the immediate disposal of all “expired” lab chemicals. In my experience, those represent the two default (and opposing) stances.

A Thought-Provoking Read

The article is well-written and raises a number of good points about a common issue facing laboratories, particularly those with budgetary constraints. I would encourage anyone associated with academic or startup laboratory facilities to give it a read.

For those who don’t have the time to read the article, the main points are:
  • There’s a lot of confusion and variability regarding manufacturers’ use of “expiration” dates
  • Scientific evidence exists for some reagents (e.g., antibodies) that shows material remaining usable well beyond the expiration date
  • Proper storage and contamination management can prolong reagent integrity
  • Retesting and validation is an option for some reagents
  • An effective chemical inventory tracking system can mitigate the issue before it becomes a problem

You may have noticed that I’ve been placing the terms “expired” and “expiration” in quotes. I’m doing this because I agree that there’s a lot of ambiguity regarding the use of expiration dates on chemicals. Until recently, expiration dates on chemicals were relatively uncommon, especially for low-hazard reagents like dry salts, buffers, and similar products. Now they seem fairly common, especially from certain vendors. In many cases, I find myself agreeing with researchers that there is little scientific basis for these expiration dates, especially for stable, dry chemicals.

What Would I Add?

With everything above in support of the “keep it if you can trust it” side, I want to highlight a few points and caveats that weren’t discussed in the original article:

  • Some expiration dates (like those for peroxide formers and polymerizers) are directly related to safety. 

In these cases, dates and reagents need to be monitored very closely. Peroxide formers and polymerizes become unstable and shock sensitive over time. Proper storage and periodic testing (e.g., with peroxide test strips) can maximize shelf life and confidence in the material, but any facility using these materials should develop clearly written policies governing their storage, handling, and routine monitoring.

For many of the common peroxide formers found in lab environments (e.g., ethyl ether, tetrahydrofuran, and 1,4-dioxane), monthly visual checks and annual strip testing (or disposal) is appropriate.

  • Expired materials cannot be used when working with animals, in GLP or GMP environments, and/or when developing products for clinical applications.

These lab environments cannot use expired materials in any context. In fact, simply having expired material on the shelf may constitute a violation. Any laboratories with animal use, GLP or GMP credentials, or clinical product development need to keep a close eye on expiration dates and remove expired material in a timely fashion.

If you find expired chemicals in these environments, take them out of the inventory immediately by moving them to a satellite accumulation area, adding a hazardous waste label, and scheduling a waste pickup.

  • It’s better (and more cost effective) to address this issue by purchasing smaller containers rather than ordering in bulk.

In the long run, conservative ordering practices and proactive inventory management systems save time and money. Ordering only what you need will save money on excess product, make inventory reconciliation easier, and reduce hazardous waste disposal costs when material needs to be removed from the laboratory.

We cover this topic in more detail in our May 1, 2019 post on chemical inventory management strategies.

  • Everyone needs to be on the same page.

A single skeptical scientist can undo an otherwise well-justified plan by ordering a new reagent. This generally guarantees that the older bottle will sit at the back of the cabinet collecting dust.For this reason, the decision to keep and continue using an “expired” material needs to be unanimous. Furthermore, all lab personnel need to make a concerted effort to used up the old material as quickly as possible.

Ways to Reconcile An Inventory With “Expired” Lab Chemicals

With these additional considerations, it becomes important to monitor and justify the use of any old or “expired” materials. With this in mind, the policy needs to include the following elements at a minimum:

  • Someone to manage the program and make decisions regarding what can stay and what needs to go.

    The lead chemist, Chemical Hygiene Officer, lab manager, or safety representative are all good candidates for this role. What’s most important is that the individual has the necessary expertise to properly assess the material. They also need the authority make final decisions about keeping or disposing of materials.

  • “Extension” parameters.

    Avoid open-ended extensions. Allowing old or “expired” material to remain in the inventory should only be considered if there’s a definitive need for the material and an immediate plan to use it. Make sure to generate a new internal “expiration” date (e.g., 6-12 months from the date of justification) for reevaluation.

  • Make a note in the chemical inventory.

    The authorized individual should make an official note in the chemical inventory to document retention decisions. Something as simple as the following would suffice, “Retention approved by Name on Date after retest/integrity assessment. Reevaluate by Date.”

While a conservative approach defaults to removing all expired lab chemicals following the manufacturer’s recommendation, I agree that there are some cases warranting some latitude. High hazard and unstable materials should never be kept beyond these dates, but a “keep it if you trust it” approach may be justifiable for low hazard materials that have been appropriately evaluated.


If you have any questions about chemical inventory management or lab cleanout and inventory reduction strategies, please contact us at info@spotlightsafetyinc.com or spotlightsafetyinc.com for a free consultation.

Photo Credit: Pixabay.com – makimuki0