Help Students Read and Understand Safety Data Sheets
4 Key Components of SDS
Undergraduate students come into your program with a wide background of laboratory experiences—from beginners taking a course for non-majors, to honors students with AP experience. It is important that all students, regardless of their previous coursework, know how to read and interpret the chemical hazard information provided on Safety Data Sheets (SDS).
4 Key SDS Components
An understanding of four key elements in every SDS will provide your students with a helpful introduction to the symbols and language used to communicate critical safety information. For reference, you can access a sample of Flinn Scientific’s SDS for n-Butyl-Alcohol available in the Resources section at the end of this article.
1. Signal Words indicate the relative level of severity of hazard and heightens the awareness of the relative risk when using a certain chemical. The signal words used in this section are ‘danger’ and ‘warning.’ ‘Danger’ is the more severe signal word. If either word is used, one should read more to learn additional details. It is important to note that there may also be no signal word, neither warning nor danger. This does not mean that the chemical is completely harmless. When used in combination with other chemicals, the mixture may not be safe.
2. Pictograms are pictorial symbols (a black symbol on a white background with a red diamond frame) that are intended to convey specific information about the hazards of a chemical. Eight pictograms exist for calling attention to the physical and health hazards with a ninth environmental pictogram that is not mandatory. For example, the Corrosion pictogram below signals to the user that the chemical may cause corrosion or burns when in contact with skin, and students should follow proper chemical hygiene procedures when handling.
Pictogram for Corrosion
It is important to note that the SDS pictograms do not replace the diamond-shaped labels that the U.S. Department of Transportation (DOT) requires for the transport of chemicals, including chemical drums, tanks or other containers.
3. Hazards Identification (refer to Section 2 of the SDS) is an overview of the physical and health hazard risks associate with using the material. The following information will help you interpret information in this section:
- The Globally Harmonized System (GHS) hazard rating of 1–4 ranks 1 as the most hazardous and 4 as the least hazardous. However, the National Fire Protection Association (NFPA) ranks 4 as the most severe. Be aware of these inverse ratings.
- Students often have questions about the LD50 values that are provided in this section. LD50 testing provides a measurement to compare the toxicity of different chemicals. LD stands for “Lethal Dose” and LD50 is the amount of material given at one time that causes the death of 50% of a group of test animals, usually rats. The value is typically expressed as the amount of chemical administered in milligrams per kilogram of body weight.
- You will see standardized GHS statements that are coded for easy reference. For example:
- Hazard or H-statement (H226) refers to: Flammable liquid and vapor.
- Precautionary or P-statements (P270) warns: Do not eat, drink of smoke when using this product.
4. Toxicological Information (refer to Section 11 of the SDS) has details on how the material may cause injury. Acute (short exposure) and chronic (long-term) effects are listed. Encourage your students to ask questions that may impact their health or the health of others. This information is especially important if any students are, or plan to be pregnant. Students should be allowed to opt out of a lab activity if they think it is not safe.
Learning how to read Safety Data Sheets is an important part of chemical education. Students need to know how to find the information necessary to make informed decisions and take all necessary precautions. Covering the 4 key topics of signal words, pictograms, and hazard and toxicology provides students with an introduction to SDS and creates an awareness and respect for chemicals that contributes to a safer laboratory experience.