Classification and labeling are important aspects of occupational health and safety. As described earlier, the designation of hazardous substances has a common basis in Europe and the United States. However, not everything corresponds completely.
What distinguishes classification from labeling?
This is an important question that can cause confusion. Classification is the summary of effects of a substance or mixture on the environment and humans. However, it also includes physical and chemical hazards. Classification consists of hazard classes and hazard categories that further quantify the hazard classes.
- Hazard class: oxidizing solids.
- Hazard coding, Europe: Ox. Sol. 2
This presentation is not always clear. For STOT SE 3 (specific target organ toxicity, single exposure 3) there are two different classifications, one with H335 (may irritate respiratory tract) and with H336 (possible drowsiness/drowsiness).
Therefore, it is worthwhile to include the H statements, or H statement codes with the classifications to differentiate. This means that in section 2.1 of the safety data sheet you suddenly see H statements and thus a component from the labeling. No wonder it is difficult to distinguish.
The labeling summarizes the classifications by means of ranking rules. This ensures that the label is not overloaded with information. 
Presentation of hazards in Europe and the US
In Europe, when the CLP Regulation was published, the abbreviated hazard classes and categories were largely translated into the individual countries. The example above was called “Oxid. Festst. 2” in the German version. In later adaptations of the CLP Regulation, the English codings have been deposited for the most part. This simplifies the presentation of the classifications in section 2.1 of the safety data sheet.
The US presentation of the hazard classes and categories is more similar to the original from the GHS than the hazard codes from Europe. Thus, according to 29 CFR 1910.1200 App C (OSHA) , a classification consists of the hazard class and category. Our example can therefore be represented as “Flammable Solids 2”.
Labelings in comparison
Both jurisdictions have ranking rules to reduce the number of pictograms on labels. Different approaches are taken with regard to safety instructions (P statements). In the European area, appropriate P statements are proposed for each classification. From these, up to six P statements are usually selected, depending on the use of the hazardous substance.
In the US, P statements are more firmly anchored with the classifications. This can easily result in more than six safety statements for hazardous material with several different hazards.
Apart from the fact that the rules for classifying a hazardous substance differ between the EU and the US, there are some classifications in Europe that the US does not have and vice versa. For example, Eye Irrit. 2 (a category in Europe) is split into Eye Damage/Irritation 2A and 2B in the US.
Determining and specifying the classification in a safety data sheet is a challenge when leaving one’s own known legal area. Software specialized in this area, such as GeSi³ from our company, may be of assistance.
While the similarity of the markings on labels makes them easier to read for users from different jurisdictions, writing the label still remains a challenge for the manufacturer.
 Regulation (EC) Nr. 1907/2006 (REACH)
 OSHA CFR 1910.1200 App D
 CLP-Regulation Nr. 1272/2008