Chemistry Solutions

Safety in the chemistry laboratory is always a concern for teachers, regardless of years of experience. Often the first resource one turns to is the chemical supplier’s Safety Data Sheet (SDS, formerly Material Safety Data Sheet, or MSDS) — but these long, dense documents can be daunting. Additionally, in 2015, major changes occurred to chemical labels and SDSs in the U.S. Many people who work and teach with chemicals are still fuzzy on the details of what has changed and what it means for them.

This article aims to increase your comfort level with SDSs. This will be done by describing the timeline showing the changes to SDS that have occurred over the last five years, discussing pros/cons of the newer SDS format, reviewing related hazard communication issues, and providing information on other resources available.

From MSDS to SDS – 2012 to now

In the U.S., requirements for SDS are determined by the Occupational Safety and Health Administration’s (OSHA) Hazard Communication Standard (HCS), 29 CFR 1910.1200. In 2012 the HCS was modified to align with the United Nation’s Globally Harmonized System of Classification and Labelling of Chemicals (GHS). GHS has been implemented internationally in over 65 countries to varying degrees. The U.S. timeline ^1,2 for adoption and implementation features five key milestones from 2012-2015:

• March 26, 2012—GHS update to OSHA issued in Federal Register.
• May 25, 2012—GHS update to US OSHA HCS goes into effect.
• December 1, 2013—Deadline to train employees on new GHS label elements and SDS format. Chemical manufacturers/importers/distributors can sell products with old labels/MSDS or new GHS compliant labels/SDS.
• June 1, 2015—Chemical manufacturers/importers must use new GHS compliant labels and SDS on anything produced.
• December 1, 2015—Chemical distributors can no longer ship containers with non-GHS compliant labels. (There was a 6-month grace period from June to December to ship previously manufactured chemicals with the older label format.)

Even with the final changes to SDSs and labels occurring over a year ago, many scientists and teachers who use hazardous chemicals every day are still unaware of the changes — or their knowledge of the change is limited to the loss of the “M” from MSDS.

The changes to align with GHS involve more than just dropping the “M.” Major changes include: a new mandatory 16-section format, required physical and health hazard classifications, hazard categories, and new SDS/label elements (pictograms, signal word, hazard statements, and precautionary statements.) Some of these changes are described in a previous Chemistry Solutions article and are detailed on the OSHA website.

The applicability of the SDS to teachers will vary by section, so the following are discussed in order from the least to most useful.

• Sections 12-15 (ecological, disposal, transport, and regulatory information) are typically the least useful sections for teachers, as their guidelines are not enforced by OSHA (instead, they’re regulated by other agencies).
• Section 16 (other information) contains supplementary information such as revision number and date.
• Sections 1 and 3 provide basic information on product name, supplier, and chemical composition; however, for more proprietary formulas (not typically used in the K-12 classroom), the chemical ingredients may be obscured with generic names or completely hidden due to trade secret claims.
• Sections 4-11 (first-aid, fire-fighting, accidental release measures, handling/storage, exposure controls/personal protection, physical/chemical properties, stability/reactivity, and toxicological info) can provide useful information. However, this will vary by supplier, as the larger chemical companies write these sections based more for large-scale industrial use than for educators in the classroom.
• Section 2, hazards identification, is the most useful section on the new SDS for a teacher, as it gives a quick and thorough overview of the hazards. In this section, manufacturers must assign and display the product's hazards according to a list of more than 25 physical and health hazard classes, which are further subdivided into hazard categories (1 = most hazardous, larger numbers = less hazardous). Each hazard class and category then triggers the inclusion of required pictograms, signal words, hazard statements, and precautionary statements, as shown in the quick reference sheet (reprinted in Figure 1). A full list of hazard and precautionary statements can be found on the United Nations Economic Commission for Europe (UNECE) website, As shown below, the variety of physical and health hazards are summarized in just nine pictograms.

Pros & Cons of the New OSHA GHS SDS/Label Requirements

Pro #1: Consistency in terminology

Labels and section 2 of the SDS are very tightly regulated under the new system. Hazards must all be classified under a set of hazard classes and categories with associated pictograms, which makes it more likely that similar hazards will be described in the same way. For example, a material considered corrosive to the skin will always display the corrosive pictogram and the hazard statement “causes severe skin burns and eye damage.” This part of the SDS for any given chemical will also have a set of required precautionary statements.

Additionally, there is a high level of consistency when describing varying degrees of toxicity. For example, the hazard statements consistently rank chemicals according to a scale from most to least toxic — i.e., from “fatal,” to “toxic,” to “harmful,” to “may be harmful.” Overall, this removes guesswork for teachers. Once you’re familiar with the hazard classes and categories, you can quickly review a label or SDS to find the most relevant hazard information, regardless of the manufacturer.

Con #1. Inconsistency in hazard classification across manufacturers

Major chemical manufacturers and distributors can disagree on how to assign the hazard classes and categories to a chemical. Although OSHA provides federal regulations for threshold values and guidelines for implementation, there is no list of standard chemicals with federally-assigned hazard classes. For example, concentrated sulfuric acid is a fairly standard chemical, but as seen in Table 1, it has a wide variety of classifications when SDSs from different suppliers are compared.

Among the seven chemical suppliers featured in Table 1, no two agree on the classification. Some of these differences arise from OSHA not completely adopting all of the GHS recommendations (for example, the environment pictogram for aquatic toxicity is non-mandatory in the U.S.). Other differences arise from varying interpretations of the chemical properties. For example, sulfuric acid is not listed as a carcinogen by the National Toxicology Program, although “strong inorganic acid mists containing sulfuric acid” is.

While it is unlikely that these conditions would be present in a K-12 teaching lab (as opposed to chemical industry), three of the chemical suppliers chose to include the carcinogenic classification, likely as a way to disclose as many potential hazards of the chemicals as possible. Similarly, this reasoning may have led to the “inhalation toxicity” and “specific target organ toxicity” classifications made by some of the suppliers.

Pro #2: Easier to identify non-hazardous chemicals

The new SDS makes it much easier to identify non-hazardous chemicals! For example, a favorite exercise among teachers has been to show students a very scary-sounding MSDS and then reveal that it is simply water. However, under the new system, section 2 of an SDS for H₂O would clearly state that the material is “not a hazardous substance or mixture,” “not hazardous according to OSHA GHS,” or “not hazardous according to 29 CFR 1910.1200.” This makes it much easier for you to identify which chemicals would pose the least hazard to your students in the classroom.

Con #2: Commonly used chemicals for demos/experiments are now classified as hazardous

Chemicals that have been used for years and are typically considered as having nonexistent or low levels of hazard may now show up as hazardous (or at least sound more hazardous) due to the new classification system. For example, Borax, a commercially available laundry detergent containing sodium tetraborate decahydrate, and commonly used in the classroom with glue to make slime, is classified as:

• skin irritation category 2 (causes skin irritation),
• eye irritation category 2 (causes serious eye irritation), and
• reproductive toxicity category 2 (suspected of damaging fertility or the unborn child).

This last classification was a surprise to me, and led me to recommend that teachers reevaluate the demos and experiments they do with students based on the new hazard classifications. Alternatively, commonly used household chemicals (e.g. shampoo) may have SDSs with corrosive pictograms because of the effect of surfactant ingredients on the eyes. Ultimately, teachers will need to perform a hazard and risk assessment for any demo or hands-on experiment planned for the classroom. In 2016, the ACS Division of Chemical Education released a revised Safety Guidelines for Chemical Demonstrations document that provides recommendations and resources to address some of these issues.

Pro #3. GHS SDS/labels implemented internationally

GHS is being implemented internationally across many countries. So, regardless of where chemicals are ordered or where students go in their future careers, the chemical labels will be consistent with the same hazard classes, pictograms, signal word, and hazard and precautionary statements.

Con #3. Countries don't adopt GHS policies equally

Countries adopting GHS are not required to adopt everything. For example, in the U.S. we only adopted the toxicity categories 1–4, but other countries also adopted a fifth category (a lower toxicity level), as seen with the Flinn Scientific classification of sulfuric acid in Table 1. Another example (mentioned in Con #1), is that the environmental hazard pictogram is non-mandatory in the U.S. As a result, occasionally you may run across an unfamiliar hazard class or category when chemicals are received from non-U.S. based chemical manufacturers. So, if an unfamiliar pictogram or hazard class is encountered, it is best to refer back to the UNECE GHS website for clarification.

Other important things to be aware of

Numbers are different!

The SDS’s numerical ranking of hazard categories is the opposite of the National Fire Protection Association (NFPA) diamond's ranking system. With the GHS categories, a low numerical ranking of 1 indicates the most hazardous category, with the hazard level decreasing as the number increases to a 4 or 5 for the lowest hazard classes in a category. With the NFPA system , the higher the number, the higher the hazard level.

Unfortunately, these conflicting numbering systems will continue to coexist because they are regulated by different organizations for different purposes. OSHA provides a QuickCard to display the differences between the NFPA 704 and GHS compliant HazCom 2012 labels. However, hope is not completely lost, as the NFPA numbers are no longer required to be on chemical labels/SDSs, and the GHS hazard category numbers are typically only displayed on the SDS.

SDS can contain errors

With the rush to complete the transition of all SDSs to the meet the new standard in 2015, many SDSs contain errors. Examples I have observed include: a liquid product with section 9 (physical/chemical properties) describing it as a “solid crystal,” a product with an incorrect color in section 9, and even physical properties that don’t make sense (e.g., a chemical with a melting point higher than its boiling point).

These errors may take a while to be fixed. According to OSHA regulations, even for SDSs that are completely correct, if a company discovers new information about a chemical and its properties, there is still a window of time before the company is legally required to update their documents (three months for SDSs, six months for labels.)

Beware the unseen hazards of store-bought chemicals!

OSHA only regulates chemicals for work use. That’s why hazardous chemicals for home use (i.e., what you'd buy at the grocery/general store) do NOT have the same required pictograms and hazard statements on the label! Often you can obtain the SDSs for such products from the manufacturer’s website. Many people may be surprised to learn that common household products can be just as hazardous, if not more so, than what is used in lab.

As mentioned above, most household shampoos will carry a corrosive pictogram, because surfactants can harm eyes. Glass-etching creams, commonly available at craft stores, contain large amounts of ammonium bifluoride, sodium bifluoride, and sulfuric acid which, when combined, can make hydrofluoric acid. Although these glass-etching cream labels will typically contain warning statements (danger, severe burns which may not be immediately painful or visible, etc.), the label will not contain the pictogram that would be required on a similar product for industrial or educational use.

So, even if you can buy a chemical at the grocery store, always find the SDS (which will contain the pictograms and hazard statements) on the manufacturer’s website before using the product in your classroom.

Final thoughts

The new SDS format brings a lot to the table, making it easier to identify hazards thanks to the increased consistency in terminology and pictograms. However, the inconsistency among manufacturers due to the quick implementation timeline, the lack of standard chemical lists with federally-assigned hazard classes, and less rigorous labeling requirements for store-bought chemicals means that educators will have to continue doing extra research on chemicals and perform a hazard and risk assessment before use in the classroom.

Additional Resources for Teachers

References

1. https://www.osha.gov/pls/oshaweb/owadisp.show_docu...
2. https://www.osha.gov/dsg/hazcom/effectivedates.htm...