Every safety data sheet has the same sixteen sections in the same order. That is by design: GHS fixed the structure so that anyone, anywhere, can find the same information in the same place without reading the whole document.
Most of it is written for the people who will handle the material — first aid, fire-fighting, spill response. If you are the person buying it, five sections carry decisions.
The five
Section 2 — Hazard identification. The classification, the signal word, the pictograms and the hazard statements. This is the summary the label is built from, and it is what determines whether the material needs controls you do not currently have. Read it before you agree a price, not after the drum is on site.
Section 8 — Exposure controls and personal protection. Occupational exposure limits, and the engineering controls and protective equipment the supplier recommends. The question this section answers is whether your facility can actually handle the material as it stands. An exposure limit that requires local exhaust ventilation you do not have is a cost, and it belongs in the decision rather than after it.
Section 9 — Physical and chemical properties. Melting and boiling point, density, solubility, vapour pressure, flash point. Two purchasing consequences hide in here: density decides whether your order weighs out or cubes out in a container, and properties like hygroscopicity and melting point decide what storage you need at the other end.
Section 14 — Transport information. UN number, proper shipping name, transport hazard class, packing group, and whether the material is a marine pollutant. This is the section that changes what a shipment costs. Dangerous goods carry documentation requirements, packaging requirements, segregation rules and surcharges that ordinary cargo does not, and a material that is regulated for transport will quote very differently from one that is not.
Section 15 — Regulatory information. The regulatory status of the substance in the relevant jurisdictions. What appears here varies by supplier and by market, and it is worth reading closely rather than assuming.
What the other eleven are for
They are not filler. Sections 4 to 7 — first aid, fire-fighting, accidental release, handling and storage — are the ones that matter at the moment something goes wrong, and they should reach the people who will be near the material rather than staying in a purchasing folder.
Sections 11 and 12, toxicological and ecological information, carry the underlying data that the classification in Section 2 was derived from. If you need to justify a decision rather than just make one, that is where the evidence is.
Section 3, composition, names the hazardous components and their concentration ranges. On a mixture this is often more informative than the product name.
Two things worth knowing
The SDS follows the jurisdiction, not the material. GHS is a UN framework that individual jurisdictions implement with variations — CLP in the European Union, HazCom in the United States. The same substance can carry a classification that reads slightly differently depending on which regime the sheet was written for. If you are importing, the sheet that governs is the one valid where the material will be used.
It is a living document. Sheets are revised as classifications change. The revision date in Section 16 tells you which version you are holding, and a sheet several years old on a substance whose classification has moved is worth replacing.