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Hazardous substance labeling: for more safety in the workplace

MedSolut AG
2022-12-15 10:52:00 / Guide
Hazardous substance labeling: for more safety in the workplace - Hazardous substance labeling: everything you need to know | MedSolut

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. Knowledge of these regulations is elementary, especially in the workplace. What hazardous substances are, what the correct hazardous substance labeling looks like and why this is so important, you can read in this blog post.

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 threshold values are grouped under this definition.

In everyday work, many people are exposed to hazardous substances, as they are widespread and include various substances and mixtures. They can be found in almost all industries and trades - from car manufacturing to food production to laboratories. Additionally, many hazardous substances are regularly encountered in everyday life. Specific examples include these representatives:

  • Gasoline
  • Acetone
  • Hydrogen
  • Varnishes and solvents
  • Disinfectants and cleaning agents
  • 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 the 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 physico-chemical, 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 given 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 authoritative. There, hazardous substances are defined as those "which 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 are classified as hazardous substances "that meet the criteria for environmental and other hazards set out in Parts 4 and 5 of Annex I to Regulation (EC) No. 1272/2008 or [...] are otherwise likely, by themselves or by their transformation products, to modify the state of the natural environment, water, soil or air, climate, animals, plants or micro-organisms 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 a globally uniform labeling, the 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:

Pictogram Coding Signal word Description
GHS01 Danger unstable explosive substances and self-reactive substances
GHS02 Attention or danger self-heating, flammable and pyrophoric gases
GHS03 Danger substances with an inflammatory (oxidizing) effect
GHS04 Attention compressed, liquefied, dissolved gases and gases under pressure
GHS05 Danger or Attention Metal corrosive substances
GHS06 Danger or Attention acute toxicity emanating from the substances
GHS07 Attention eye irritant and/or skin irritant
GHS08 Danger or Attention various dangers for the health
GHS09 Without signal word or attention substances hazardous to the aquatic environment

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 equipped with a pictogram, signal word and the hazard and precautionary statements (risk and safety phrases, H and P phrases). These are codified warning statements.


The R-phrases refer to special risks of the hazardous substances, which is elementary for immediate measures in case of accidents. The coding consists of an "R" and a corresponding number. R 1 begins with explosive substances, R 10 to R 12 form the flammable to highly 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 handling hazardous substances that must be observed as mandatory action maxims. S 1 means, for example, that the substance must be kept under lock and key, S 22 means that the dust must not be inhaled. S 31, for example, means that explosive substances must be kept away from, while S 39 requires safety goggles 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 locked up 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 defined in the UN Recommendations on the Transport of Dangerous Goods and are indicated on an orange warning plate. In each case, they are located below 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, this is an oral intake. Liquids and dusts are particularly affected.

Dermal: In the case of skin contact, we speak of dermal absorption. 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. A common example is needlestick injuries.

Potential health risks

The potential health hazards that may arise if the hazardous substance is ingested are also subject to classification. Again, these labels 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

Point 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

Point 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 for classification and labeling of chemicals and hazardous substances, which are anchored in different regulations. In addition to the CLP Regulation and the GHS, there are, for example, dangerous goods classes and storage obligations that 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 obliged to provide training and to appoint a safety officer. The supplementary protective measures for hazardous substance labeling must be carried out in a specified sequence:

  1. Avoidance/elimination of sources of danger or potential for exposure.
  2. Technical protective measures
  3. Organizational protective measures
  4. Personal protective measures
  5. Behavior-related protective 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.

Die Kennzeichnungspflicht liegt beim jeweiligen Unternehmen oder Produzenten, der die gefährlichen Stoffe in den Verkehr bringen bzw. von dort aus weiterverarbeiten.

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 laid down in the CLP Regulation.

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