Not All Labware Is Created Equal by Greg Kwolek

Four laboratory incidents caused by chemicals stored within incompatible containers were reported to EH&S in 2013, all of which resulted in inadvertent hazardous materials releases. The three material classes used most frequently in the manufacture of laboratory containers are glass, metal, and plastic. All are useful for chemical storage, under the right circumstances, but they cannot always be utilized interchangeably. Each material possesses different chemical resistance characteristics. If a container that is chemically incompatible with its contents is selected, the container can degrade to the point of failure, potentially resulting in a hazardous materials release and exposure. For this reason, selecting a container for chemical storage must
be done with great care.

Most commonly found in laboratories, and preferred for most chemical storage applications, are clear borosilicate or amber glass containers that typically exhibit a high degree of chemical resistance and are a sound storage choice for most chemicals, with a few exceptions. Some chemicals are capable of etching the surface of glass, potentially weakening the structure of the container to the point of failure. For this reason, storing chemicals such as hydrofluoric acid and concentrated hydroxide solutions in glass containers should be avoided.

Plastic containers are made of many different polymers with varying degrees of chemical resistance. Chemicals can decrease the integrity of polymers by physical and chemical means. Similar solubility parameters or polarities often result in the incompatibility of a polymer and chemical. Therefore, a plastic container compatible with the chemical contents must be selected by evaluating materials that have suitable resistance properties. In two recent incidents a concentrated potassium hydroxide solution degraded a polyethylene terephthalate (PETG) container. In a third, a dichloromethane solution quickly dissolved a polystyrene (PS) container. All could have been avoided by more careful container selection.

Metal containers, commonly produced from aluminum and stainless steel fare well with organic solvents, but are susceptible to damage from many corrosive chemicals. In a recent incident a 20 liter steel drum was repurposed as a hazardous waste container. The drum was primarily used to collect organic solvents, but some acidic material was inadvertently added, causing the drum to corrode and leak. In general, metal containers must be used with caution, and EH&S discourages the repurposing of metal containers for hazardous waste collection.

So how can you select the best chemical storage container? Firstly, if you keep chemicals in the primary container in which they are shipped, you have the greatest chance of avoiding an accidental release due to incompatibility. However, if you must transfer chemicals to a secondary container, selecting a chemically compatible container is made easiest by referencing chemical resistance and compatibility guides published on container manufacturers’ websites. Container manufacturers expose their products to a variety of chemicals under typical experimental conditions (e.g., at room and elevated temperatures) in order to observe changes in visual appearance, mass, and by applying tensile and impact stresses to the materials after exposure. Questions? Please don’t hesitate to contact a Research Safety Specialist at labsafety@columbia.edu.

Laboratory Chemical Inventory Audit started

As part of a quality assurance for chemical tracking in the Morningside laboratories, the ChemTracker audit has begun. Please be sure to discard empty chemical containers in the yellow bins (hallways) so that the bottles can be scanned out.

Please also show all your chemical bottles to the auditor so that they can be scanned. In the past, the primary discrepancy is that discarded containers were not scanned out which resulted in an inaccurate chemical inventory.

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