How to Read an SDS and Decode GHS Labels

A plain-English guide to reading a Safety Data Sheet: the 16 SDS sections, which to read first, GHS pictograms and signal words, and how H- and P-codes work.

How to Read a Safety Data Sheet (and Decode GHS Labels)

Quick answer: Every hazardous chemical at your workplace comes with a Safety Data Sheet (SDS) in a fixed 16-section format and a label built from standardized GHS elements — a signal word, hazard pictograms, and H- and P-code statements. Learn to read the signal word and pictograms first, then jump to the SDS sections that tell you how to protect people: hazards (2), first aid (4), handling and storage (7), and exposure controls and PPE (8). Decode any label in seconds with our free GHS & SDS decoder.

A worker reading a chemical safety data sheet next to labeled containers

What an SDS is — and why it is required

Under OSHA's Hazard Communication Standard (29 CFR 1910.1200), chemical manufacturers must classify the hazards of their products and communicate them through labels and Safety Data Sheets. Your employer must keep an SDS for every hazardous chemical on site and make them readily accessible to employees during every shift. The HazCom Standard is aligned with the Globally Harmonized System (GHS), which is why labels and sheets look consistent across manufacturers and countries.

The 16 sections — and the ones to read first

Every SDS follows the same order, so you always know where to look. Sections 1 through 11 and 16 are enforced by OSHA; sections 12 through 15 are internationally harmonized but not OSHA-enforced.

1. Identification — product name, manufacturer, and emergency phone number.
2. Hazard(s) Identification — the classification, signal word, pictograms, and hazard statements. Start here.
3. Composition / Ingredients — the hazardous components and their concentrations.
4. First-Aid Measures — what to do for exposure by each route.
5. Fire-Fighting Measures — suitable extinguishing media and fire hazards.
6. Accidental Release Measures — spill containment and cleanup.
7. Handling and Storage — safe practices and incompatibilities.
8. Exposure Controls / PPE — exposure limits, engineering controls, and required PPE.
9. Physical and Chemical Properties — appearance, odor, flash point, and more.
10. Stability and Reactivity — conditions and materials to avoid.
11. Toxicological Information — health effects and toxicity data.
12–15 — ecological, disposal, transport, and regulatory information (non-mandatory under OSHA).
16. Other Information — the preparation or revision date.

For a fast hands-on response, the four sections that matter most are 2 (hazards), 4 (first aid), 7 (handling and storage), and 8 (exposure controls and PPE).

Decoding the label

A compliant GHS label carries six elements: product identifier, supplier information, signal word, hazard pictograms, hazard statements, and precautionary statements.

Signal word. A label shows one of two words. Danger marks the more severe hazards; Warning marks the less severe ones. A label never shows both — if any hazard rates "Danger," that is the word used.

Pictograms. The red-bordered diamonds tell you the type of hazard at a glance — a flame for flammables, a skull for acute toxicity, the corrosion symbol for chemicals that burn skin or metal, the health-hazard symbol for carcinogens and other serious long-term effects, and so on. OSHA requires eight pictograms; the environment pictogram is part of GHS but is not required on U.S. labels.

H- and P-codes. Hazard statements (H-codes) describe the danger — for example, H314, "Causes severe skin burns and eye damage." Precautionary statements (P-codes) tell you what to do about it — for example, P280, "Wear protective gloves and eye protection." Our decoder lets you look any of them up.

How to actually use an SDS on the floor

Before first use of a chemical: read Section 2 for the hazards and Section 8 for the PPE you need.
When storing it: check Section 7 and Section 10 for incompatibilities so you do not store reactive chemicals together.
If there is a spill: go to Section 6, and Section 5 if there is a fire risk.
If someone is exposed: Section 4 gives the first-aid steps; Section 1 has the emergency phone number.

Common mistakes

Treating "Warning" as harmless. It still signals a real hazard — just a lower category than "Danger."
Ignoring Section 8 exposure limits (PEL/TLV) and skipping the required PPE.
Letting SDSs go stale. Sheets should be the current manufacturer version and accessible on every shift.
Storing incompatible chemicals together because no one checked Section 7 or 10.

Key takeaways

✓ SDSs always follow the same 16-section order — sections 1–11 and 16 are OSHA-enforced.
✓ Read Sections 2, 4, 7, and 8 first for a fast, safe response.
✓ The signal word is "Danger" (severe) or "Warning" (less severe), never both.
✓ Pictograms show the hazard type; H-codes name the danger and P-codes give the precautions.
✓ Keep every SDS current and accessible on every shift.

Build It Into Your Safety Program with Vetted Safe

Knowing how to read an SDS is half the battle — keeping every sheet current is the rest. Vetted Safe's SDS Library auto-extracts hazard data on upload, flags sheets that are due for review, and keeps your whole chemical inventory searchable and audit-ready.

Explore the HSE platform or see plans and pricing to put your whole safety program in one place.