On March 11, the American Chemical Society’s Division of Chemical Health and Safety (CHAS) held an on-line “CHAS-chat” that discussed Quality Data for Safer Experiments. Given the increasing use of general-purpose search engines such as Google to collect hazard information, assessing the quality of safety information is becoming a more important skill for both chemists and the EHS professionals who support them. The CHAS chat discussion focused on assessing the quality of chemical safety data available to laboratory workers as they conduct risk assessments of chemical processes.
This CHAS chat used the hazards of dimethyl sulfoxide (DMSO), a chemical found both in households and in laboratories, as its starting point. DMSO is used as a home and veterinary remedy and, in the laboratory, as an important chemical solvent. These diverse uses means that the quality of information about the hazards of DMSO varies widely, depending on the audience it is written for.
For example, websites that discuss its use as a “miracle healer” focus on the potentially hazardous side effects of exposure to the chemical itself. Because DMSO penetrates human skin quite effectively, it is often used as a topical agent, either by itself or in combination with other drugs which are being used for therapeutic purposes. However, DMSO can also help carry unintended toxic contaminants through the skin. This property is not often described on web sites about the medical uses of the product.
In the laboratory, an additional set of concerns arise when using DMSO. For example, an unusual feature of DMSO is that its melting point is quite close to room temperature (65 degrees F). This means that in cool rooms it may solidify as it freezes. When this occurs, EHS workers not familiar with this property may mistake the solid for a potentially explosive organic peroxide. Fortunately, a review of the Safety Data Sheet for DMSO can identify this property and dispel this concern.
However, the physical hazards of DMSO become of more concern when it is mixed with other chemicals. Because the GHS focuses on the hazards of the chemical by itself, many SDSs do not include such information. However, Laboratory Chemical Safety Summaries from the PubChem branch of the National Library of Medicine include a section on chemical reactivity which is collected from publicly available sources. On the DMSO LCSS, the chemical is described as reacting violently on contact with many acyl halides and related compounds.
However, this reactivity information on the LCSS is broad and more information is often necessary to develop a complete hazard assessment for a specific laboratory use of DMSO. More detailed information about the hazards of DMSO can be found in the chemistry literature. For example, during the CHAS chat, an overview of more 100 articles about safety issues related to DMSO from the Organic Process Research and Development journal was presented.
These many layers of chemical safety information are important considerations to EHS managers overseeing a collection of hazardous chemical inventory information, both as they plan how to use this inventory information for laboratory chemical risk assessment and how they report these hazards to local emergency planners.
For more information about this topic, you can check out the CHAS Chat recording on the CHAS web site.
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Ralph Stuart, CIH, CCHO is the Environmental Safety Manager at Keene State College in Keene, NH. He has over 30 years of experience in addressing Indoor Air Quality concerns and optimizing laboratory ventilation for safe energy conservation. He is the past chair of the American Chemical Society’s Committee on Chemical Safety.