Safety data sheets (SDSs) are seemingly ubiquitous, especially for a company that handles a wide variety of chemicals. They are a regulatory requirement and employees are annually trained (hopefully) on how to access and read them as part of their HAZCOM requirement. Astute readers may even know each of the 16-sections that SDSs contain. For a lot of safety professionals, especially those at smaller organizations, SDSs are also the first (and sometimes only) place they turn when performing chemical risk assessments. In this post, we’ll explore why this approach to chemical risk assessments should be performed with caution.
Inconsistent Hazard Classification
If your chemical risk assessment follows the paradigm put forth in the 1983 publication Risk Assessment in the Federal Government: Managing the Process, then your process begins with hazard identification. SDSs are a logical place to try and find the hazards associated with chemicals. After all, that’s their intended purpose. However, most readers of SDSs will almost certainly identify the blatant lack of consistency between different SDSs for the same chemical.
Take for example the substance methyl 4-aminobenzoate (CAS # 619-45-4). This common laboratory material is sold by a myriad of vendors, each of which is legally required to supply an SDS. The image below shows an excerpt of Section 2 (Hazard Identification) for the substance from three different vendors (who shall remain nameless). Notice anything? The first SDS identifies skin and eye irritation as well as a target organ effect on the lungs. The second excerpt identifies only skin and eye irritation while making no mention of an effect on the lungs. Worse still, the third excerpt claims that methyl 4-aminobenzoate is non-hazardous. The authors of the third SDS apparently didn’t put much time or effort into the document. Such inconsistencies are rampant throughout the chemical industry.
For folks looking to perform a risk assessment, they are clearly at the mercy of whichever SDS that happens to be in front of them. The drastic difference in SDS quality makes for an incredible amount of uncertainty, and if there is that much uncertainty at the very start of the risk assessment, the final product may not be worth the paper it is printed on.
And the drastic difference in SDS quality exists primarily because…
Anybody Can Write an SDS
Yep. That’s not a typo. Literally anyone can author an SDS so long as the product meets the OSHA/GHS format requirements. Far too often the task of authoring an SDS falls to someone who has not been thoroughly trained in the GHS decision logic. The GHS handbook, now in its 10th edition, contains a multitude of road maps on how to assign appropriate hazard categories to a substance and ensure labeling is correct. Authoring an SDS is not an easy task and one that should not be taken lightly, but not knowing if the author is properly qualified to do so adds even more uncertainty to the content and validity of many SDSs.
Yet there are properly trained individuals out there who can correctly author an SDS. The AIHA offers an SDS & Label Authoring Registry, a professional credential that validates the knowledge and skill level of the individual. Unfortunately, there are only 91 SDSRPs around the world, a number that should make all SDS users cringe. Odds are that your SDS you are using was not authored by someone with the SDSRP credential.
Yet even if the document is authored by a knowledgeable individual, the user of the document should still have uncertainty because…
There Is No Requirement For References
If you were to peruse the scientific literature of peer reviewed articles on literally any topic, you will find that they are rife with references. Prior studies, review articles, data sources, and a plethora of other primary and secondary sources are all cited in articles. References are a means to allow the reader to track down the original source material and read it for themselves.
Interestingly, there is no requirement (or logical place) for references in an SDS. Considering that the assignment of hazards are supposedly based on toxicological data, it is curious indeed that the document does not allow for the placement of references. An SDS author can choose any study to base the decision logic upon, but is it a quality study? Is the author qualified to make that assessment? Without being able to read the source material upon which the conclusions are based, we are again at the mercy of the author.
The question of using quality data to construct an SDS becomes even more important if the reader wishes to obtain information from Section 11. That section of an SDS is the “Toxicology” section, and usually lists LD50 values for substances. It is not surprising to see information stating a material is genotoxic in a particular assay or showed reproductive effects in animals, etc. But were the studies well designed? For that matter, the LD50 values often seen can be questioned if the studies were not well executed. The toxicology literature is vast, and there are a number of excellent studies but also a number of not-so excellent studies. Without providing a citation so that we can gauge the quality of the data, we are left with an increasing amount of uncertainty surrounding the conclusions.
So Where To Start With Chemical Risk Assessments?
If an SDS is not a great tool for performing risk assessments, where should safety professionals begin? There are a number of databases that contain publicly available data that can be good starting points. PubChem, ECHA, US National Toxicology Program, US EPA Integrated Risk Information System (IRIS), and the OECD eChemPortal are all excellent sources of information. All of these databases provide references and draw from the primary literature, allowing the user to make an informed decision as to how viable the information is.
Unfortunately, most materials in commerce do not have much information known about them. The obligatory “no data available” that is often seen in an SDS can (sometimes) be attributed to this fact. When situations such as these present themselves, it is important to not equate “no data available” with “not hazardous”. The materials are simply not yet tested. Seeking expert advice on how to best proceed (toxicologists, consultants, subject matter experts, etc.) should be the best course of action.
Final Thoughts
Chemical risk assessments are by their very nature time consuming and difficult. Not to mention frustrating at times. Seeking out quality information to base your decisions upon greatly reduces uncertainty and can give more confidence during the decision-making stages of the risk management process. SDSs are a nice tool to have and can be useful when they are authored correctly, but they should be used with caution in the risk assessment process.
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