Free lesson · 3 min read · Updated 2026-10-25
How to Read a Safety Data Sheet (SDS): All 16 Sections Explained
Every hazardous chemical sold in the United States ships with a safety data sheet. OSHA's Hazard Communication Standard (29 CFR 1910.1200) requires manufacturers and importers to write one, and employers to keep it readily accessible to workers on every shift. On a hazardous waste site or during a spill, the SDS is often the fastest way to learn what a chemical can do to you and how to protect yourself.
The format: 16 sections in a fixed order
Since HazCom was aligned with the Globally Harmonized System (GHS), every SDS uses the same 16 headings in the same order (Appendix D to 1910.1200). Once you know where things are, you can find answers in seconds.
| # | Section | Look here for |
|---|---|---|
| 1 | Identification | Product name, recommended use, supplier, emergency phone number |
| 2 | Hazard(s) identification | Hazard class, signal word, pictograms, hazard and precautionary statements |
| 3 | Composition / ingredients | Chemical names, CAS numbers, concentrations |
| 4 | First-aid measures | What to do for inhalation, skin, eye and ingestion exposures; key symptoms |
| 5 | Fire-fighting measures | Suitable extinguishing media, hazardous combustion products, firefighter PPE |
| 6 | Accidental release measures | Spill PPE, containment and cleanup methods |
| 7 | Handling and storage | Safe handling, incompatible materials, storage conditions |
| 8 | Exposure controls / personal protection | OSHA PELs, ACGIH TLVs, engineering controls, gloves, respirators |
| 9 | Physical and chemical properties | Flash point, vapor pressure, vapor density, pH, solubility, explosive limits |
| 10 | Stability and reactivity | Conditions and materials to avoid, hazardous decomposition products |
| 11 | Toxicological information | Routes of exposure, symptoms, acute and chronic effects, carcinogenicity |
| 12-15 | Ecological, disposal, transport, regulatory | Required on the sheet, but OSHA does not enforce their content because other agencies regulate those areas |
| 16 | Other information | Date of preparation or last revision |
Section 2: reading the hazard summary
Section 2 is the one-glance summary, and it matches the container label.
- Signal word. "Danger" is used for the more severe hazards and "Warning" for the less severe. Only one appears.
- Pictograms. Red-bordered diamonds: flame, flame over circle (oxidizer), exploding bomb, gas cylinder, corrosion, skull and crossbones, exclamation mark, health hazard (the silhouette with a starburst) and environment. OSHA does not require the environment pictogram.
- Hazard statements describe the hazard ("Causes severe skin burns and eye damage"). Precautionary statements tell you what to do ("Wear protective gloves").
The sections a field worker uses most
When you are deciding how to work safely, go straight to these:
- Section 8 for exposure limits and the PPE the manufacturer recommends. Compare the limits with your air monitoring readings.
- Section 9 for flash point (fire risk), vapor density (above 1 means vapors sink into low areas) and the lower and upper explosive limits.
- Section 10 for incompatibles, so you don't store or bulk a waste with something it reacts with.
- Section 4 before work starts, so first aid isn't a surprise.
- Section 6 if something spills.
Limits of an SDS
- It describes the product as sold. Waste mixtures, aged drums and reaction products may behave differently.
- Glove advice is often general ("chemical-resistant gloves"). Check a glove manufacturer's permeation chart for the actual chemical.
- Check the revision date in Section 16 and ask for the current sheet if it looks old.
- On an unknown-waste site there may be no SDS at all, which is why site characterization and air monitoring come first.
Test yourself with the SDS and GHS quiz.
Frequently asked questions
How many sections are on a safety data sheet?
Sixteen, always in the same order, as required by OSHA 29 CFR 1910.1200 Appendix D.
Which SDS section lists the PPE to wear?
Section 8, Exposure controls/personal protection, which also lists exposure limits such as OSHA PELs and ACGIH TLVs.
What is the difference between the signal words Danger and Warning?
Danger is used for more severe hazards and Warning for less severe hazards. Only one signal word appears on a label or SDS.
This guide summarizes federal OSHA, Cal/OSHA and EPA rules for training purposes. It is not legal advice. Always check the current regulation text and your site safety and health plan.