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While Section 1 of an SDS establishes basic, yet essential information, Section 2 is the most important because it identifies the hazards of the chemical. This section includes the hazard classification of the chemical, signal word, hazard statement(s), pictograms, the precautionary statement, and description of any hazards not identified yet.1

Hazard Classes

There are 29 different hazard classes in GHS that describe the nature of the chemical hazard. Classifications range from explosives to skin corrosion to hazardous to aquatic environment, among others. While each hazard class has its own criteria, the rule of thumb is the lowest number signifies the most severe hazards. For example, flammable liquids can be divided into 4 categories with category 1 representing the most severe hazard.2

Signal Words

The only two signal words specified in GHS are danger and warning. If “danger” is displayed on a GHS label or SDS that indicates severe hazard is present. “Warning” indicates less severe hazard, but still recognizes that there is risk involved. A label or SDS should never have both “danger” and “warning” displayed. GHS does not require a signal word, depending on the chemical classification. The absence of a signal word does not mean that the chemical is harmless, but that the risk associated with the chemical is less. 3

Hazard Statements

Hazard statements are standard phrases assigned to a hazard class and category paired together. Each statement has a designated code for the pair. The code starts with ‘H,’ and is followed by three digits. The first digit describes the type of hazard present in the chemical: 4

  • Physical hazard = 2
  • Health hazard = 3
  • Environmental hazard = 4

A chemical can have multiple hazard statements. It is important to note that the associated phrase is displayed on the SDS and label, not the code. In the example shown below, under “Hazard Identification,” “Causes Skin & Serious Eye Irritation” is displayed on the label, not “H315” and “H319.”

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