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So gelingt die richtige Gefahrstoffkennzeichnung

Hazardous substance labeling: for more safety in the workplace

| von Julia

Substances and mixtures that have a harmful effect on humans and/or the environment are referred to as hazardous substances. They are subject to many laws and regulations on labeling, classification and handling. Gerade am Arbeitsplatz ist die Kenntnis dieser Vorschriften elementar. Read this blog post to learn what hazardous materials are, what proper hazardous material labeling looks like, and why it’s so important.

What are hazardous substances?

When we talk about hazardous substances, we are talking about different substances with a harmful effect on humans (and often also on the environment), so that they potentially cause acute and/or chronic damage. In addition, substances that exceed certain limits are grouped under this definition.

In everyday work, many groups of people come into contact with hazardous substances, as these are widespread and include diverse substances and mixtures. They can be found in almost all industries and trades – from car manufacturing to food production to laboratories. In addition, many hazardous substances occur regularly in everyday life. Specific examples include these representatives:

  • Gasoline
  • Acetone
  • Hydrogen
  • Varnishes and solvents
  • Disinfectants and detergents
  • Wood dust

Hazardous substances within the meaning of the Hazardous Substances Ordinance

The legal basis for classification as a hazardous substance is found in both the Hazardous Substances Ordinance (GefStoffV) and the Chemicals Act. According to GefStoffV, all such substances count as hazardous substances that comply with § 3, are explosive or “from which hazardous substances are formed or released during manufacture or use“.

The same applies to substances and mixtures “which do not meet the criteria for classification but which, because of their physicochemical, chemical or toxic properties and the way in which they are present or used in the workplace, may endanger the health and safety of workers” or which have been assigned an occupational exposure limit.

Hazardous substances within the meaning of the Chemicals Act

In addition, the regulations of the Chemicals Act (ChemG) and the CLP Regulation (EC) No. 1272/2008 are applicable. There, hazardous substances are defined as those that “meet the criteria for physical hazards or health hazards set out in Parts 2 and 3 of Annex I to Regulation (EC) No 1272/2008 or […] are dangerous to the environment.”

In addition, mixtures and substances belong to hazardous substances “listed in Annex I, Parts 4 and 5 of the Regulation (EC) No. 1272/2008 meet the criteria set out for environmental hazards and other hazards or […] are themselves, or their transformation products are otherwise capable of altering the state of the natural environment, water, soil or air, climate, animals, plants or microorganisms in such a way that hazards to the environment may be caused immediately or subsequently”.

This is how you succeed in labeling hazardous substances correctly

Not only the definition of hazardous substances, but also the correct and necessary hazardous substance labeling is regulated by law in EC law and the CLP Regulation. In order to create uniform labeling worldwide, GHS labeling (Globally Harmonized System of Classification and Labeling of Chemicals) has been mandatory since December 1, 2012. It consists of signal words and corresponding pictograms:

PictogramCodingSignal wordDescription
GHS01Dangerously unstable explosive substances and self-reactive substances
GHS02Caution or Dangerflammable and Pyrophoric Gases
GHS03Hazardous flammable (oxidizing) substances
GHS04CautionCompressed, liquefied, dissolved gases and gases under pressure
GHS05Hazard or Warning Metal Corrosive Substances
GHS06Danger or CautionAcute toxicity arising from the substances.
GHS07Caution Eye and/or skin irritant
GHS08Danger or WarningMiscellaneous Health Hazards
GHS09Without signal word or CautionAqueous Hazardous Substances

Hazardous substance labeling with R and S phrases

In the case of purely internal use, it is sufficient to label the hazardous substances with the appropriate hazardous substance pictograms including subtitles. Otherwise, the substances must be provided with a mandatory pictogram, signal word and the hazard and precautionary statements (risk and safety phrases, H and P phrases). These are codified warnings.


The R-phrases refer to special risks of the hazardous substances, which is elementary for immediate measures in case of possible accidents. The coding consists in each case of an “R” and a corresponding number. R 1 starts with explosive substances, R 10 to R 12 form the flammable to extremely flammable series, R 45 and R 46 indicate a cancer risk and a possible change in genetic material, respectively.

The R-phrases do not have to stand alone, but can also be combined internally – in this way, related hazards can be classified. However, the permissible combinations are specified. As an example, the sentence R 39/23/24 can be mentioned, which stands for “Toxic: danger of serious irreversible effects through inhalation and in contact with skin”.


In contrast to the R-phrases, the S-phrases provide safety advice for the handling of hazardous substances, which must be observed as mandatory action maxims. S 1 means, for example, that the substance must be kept under lock and key, while S 22 means that the dust must not be inhaled. For example, S 31 must be kept away from explosive substances, while S 39 requires safety glasses and face protection.

S-phrases can also be combined to cover multiple safety advisories. A common everyday example is S 1/2, which stands for “Keep under lock and key and out of reach of children.”

UN numbers

If dangerous goods are to be transported, they must also be given a UN number. These are specified in the UN Recommendations on the Transport of Dangerous Goods and are indicated on an orange warning sign. They are each under the hazard number. Examples are 1203 for gasoline or 1428 for sodium.

Risks associated with a lack of hazardous substance labeling?

If hazardous substance labeling is missing or carried out inadequately, there is a risk of health consequences – these depend on the respective hazardous substance and the route of ingestion.

Recording paths

In principle, hazardous substances can be absorbed into the human body in four different ways. These are the following:

Inhalation: The hazardous substance is inhaled and absorbed into the body through the nose. This hazard applies in particular to gases, vapors, dusts and aerosols.

Oral: If the hazardous substance enters the body through the mouth, it is an oral intake. Liquids and dusts are particularly affected.

Dermal: In the case of skin contact, this is referred to as dermal uptake. This occurs by absorption and is often the case with liquids, vapors and dusts.

Subcutaneous: If a foreign body penetrates under the skin, absorption occurs subcutaneously. Needlestick injuries are a common example.

Potential health risks

The potential health hazards that may result from ingestion of the hazardous substance are also subject to classification. Again, these markings lead to a quick and appropriate response to an accident, so they are required by law. A corresponding list can be found in the CLP Regulation and contains the following health hazards:

Item 3.1: Acute toxicity

Point 3.2: Corrosive/irritant effect on the skin

Item 3.3: Serious eye damage/eye irritation

Point 3.4: Sensitization of the respiratory tract or skin

Point 3.5: Germ cell mutagenicity

Point 3.6: Carcinogenicity

Item 3.7: Reproductive toxicity

Item 3.8. and 3.9.: Specific target organ toxicity

Item 3.10.: Aspiration hazard

Hazardous substances and legal regulations

The law provides several specifications on the system of classification and labeling of chemicals and hazardous substances, which are embodied in different regulations. In addition to the CLP Regulation and the GHS, there are also, for example, dangerous goods classes and storage obligations, which can be found in the Technical Rules for Hazardous Substances Storage of Hazardous Substances in Transportable Containers TRGS 510.

Hazardous substance labeling in the workplace is mandatory

The correct classification, labeling and handling of hazardous substances can ensure the best possible safety in the workplace. In addition to compliance, the employer is also required to provide training and a safety representative. The supplementary protective measures for hazardous substance labeling must be carried out in a specified sequence:

  1. Avoidance/elimination of sources of danger or stress potentials
  2. Technical protective measures
  3. Organizational protective measures
  4. Personal protective measures
  5. Behavioral protection measures


The difference between a hazardous material and a dangerous good is in transportation – while every hazardous good is a hazardous material, only hazardous materials in transportation count as dangerous goods.

A hazardous substance must be provided with both a GHS label and a suitable pictogram and signal word. For non-internal uses, R-phrases and S-phrases as well as UN numbers are added.

The labeling obligation lies with the respective company or producer who places the hazardous substances on the market or processes them from there.

GHS stands for “Globally Harmonized System of Classification and Labelling of Chemicals” and represents a globally valid classification system for the labeling of hazardous substances. It is specified in the CLP Regulation.

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