Dangerous substances


Dangerous substances — any liquid, gas or solid that poses a risk to workers’ health or safety — can be found in nearly all workplaces. Across Europe, millions of workers come into contact with chemical and biological agents that can harm them.

In fact, in 2015, 17% of workers in the EU reported being exposed to chemical products or substances for at least a quarter of their working time, a proportion practically unchanged since 2000, and 15 % report breathing in smoke, fumes, powder or dust at work.

Some highly dangerous substances — such as asbestos or polychlorinated biphenyls (PCBs) — are now banned or under strict control. However, other potentially harmful substances are still widely used, and legislation is in place to ensure that the risks associated with them are properly managed.

The risks to health

The health problems that can be caused by working with dangerous substances range from mild eye and skin irritation to severe effects, such as birth defects and cancer. Effects can be acute or long term, and some substances can have a cumulative effect. Some of the most common dangers are:

Some dangerous substances pose safety risks, such as risk of fire, explosion or suffocation. In addition, dangerous substances normally have several of these properties.

Biological agents

Bacteria, viruses, fungi and parasites are found in many sectors. They are usually invisible, which means that the risks they pose may not be considered.

Workers in some sectors are in particular danger of being exposed to harmful biological agents: healthcare, agriculture, veterinary services, cleaning and maintenance, sewage and waste management, gardening and laboratory work.

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Emerging risks

New technologies, expanding sectors and changes to the way work is organised can result in greater risk of harm from biological or chemical agents. In the environmental sector, for example, innovative technologies can entail poorly understood risks. To give another example, more and more workers are exposed to dangerous substances in service professions such as home care and waste management, where the exposure is varied but awareness of the hazards involved is low. More than ever, it’s vital that employers and workers understand the potential risks and take preventive action.

Find out more on emerging risks, green jobs and nanomaterials.

More information related to emerging risks:

Preventive measures and management of dangerous substances

To protect workers from dangerous substances, the first step is to carry out a risk assessment. Then, actions should be taken to remove or reduce the risks as far as possible. And, finally, the situation should be regularly monitored and the effectiveness of the steps taken reviewed.

Member States as well as EU-OSHA have developed a number of models to help small and medium-sized enterprises to carry out risk assessment. The Dangerous Substances e-tool provides employers with the support and advice they need to effectively manage dangerous substances in the workplace. A database of practical tools and guidance  contains practical measures for workplaces, such as guidance on risk assessments and how to substitute or eliminate the use of dangerous substances, case studies and a variety of instruments.

Read more on the OSHwiki page about risk management tools for dangerous substances

Employers also need to take into account any vulnerable groups, such as workers who are young, pregnant or breastfeeding, for whom special protection is required by law. Other groups of workers, such as migrant workers, untrained or inexperienced staff, and contractors, such as cleaners, also need to be considered and prevention tailored to their needs.

Hierarchy of prevention

European worker protection legislation establishes a hierarchy of measures that employers need to take to control the risks to workers from dangerous substances.

  • Elimination and substitution are at the top of the hierarchy of control measures. Where possible, eliminate the use of dangerous substances by changing the process or product in which the substance is used.
  • If elimination is not possible, substitute a non-hazardous or less hazardous substance for the dangerous one.
  • If a substance or process cannot be eliminated or substituted, the exposure can be prevented or reduced by technical and organisational solutions. These are, for example, control of the emission at the source (closed system or local exhaust ventilation), or reducing the number of workers exposed to the dangerous substance, and the duration and intensity of exposure.
  • By law, using personal protective equipment (PPE) is the last resort where exposure cannot be adequately controlled by other means.

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Good communication

To ensure their safety, workers should be kept informed about:

  • The findings of their employer’s risk assessments
  • The hazards they are exposed to and how they may be affected
  • What they have to do to keep themselves and others safe
  • How to check and spot when things are wrong
  • Who they should report any problems to
  • The results of any exposure monitoring or health surveillance
  • Preventive measures to be taken in case of maintenance work
  • First aid and emergency procedures

Read EU-OSHA’s e-fact on dangerous substances and successful workplace communication

Occupational exposure limits

For a number of dangerous substances, the EU and Member States have set Occupational Exposure Limits (OELs) that need to be respected.
Binding (which means that they must be met) and indicative (as an indication of what should be achieved) OEL values for dangerous substances are also laid down in European OSH directives. OELs for hazardous substances are important information for risk assessment and management. Most EU Member States establish their own national OELs, usually including more substances than the EU directives. However, OELs have been set for only a limited number of the substances currently used in the workplace.


There are many dangerous substances classified as carcinogens to which workers may be exposed. Some are generated by work processes themselves.

There are specific provisions in the EU to protect workers. According to the Carcinogens Directive, employers must assess and avoid or minimise the exposure to carcinogens or mutagens. In addition to applying the hierarchy of prevention measures:

  • They shall replace a carcinogen or mutagen in so far as is technically possible with a substance, mixture or process which is not or is less dangerous.
  • Where this is not possible, ensure that it is, in so far as is technically possible, manufactured and used in a closed system.
  • Where a closed system is not technically possible, employers shall reduce exposure to as low as is technically possible, limiting the quantities and keeping the number of workers exposed as low as possible.

They must also:

  • Demarcate risk areas and use adequate warning and safety signs
  • Design the work processes so as to minimise the substance release
  • Evacuate carcinogens or mutagens at source, but respect the environment
  • Use appropriate measurement procedures (especially for early detection of abnormal exposures from an unforeseeable event or accident)
  • Use individual protection measures if collective protection measures are not enough
  • Provide for hygiene measures (regular cleaning)
  • Draw up emergency plans
  • Use sealed and clearly and visibly labelled containers for storage, handling, transportation and waste disposal

They also have specific information requirements for workers and authorities and need to keep records of exposed workers, measurements and health surveillance results.

OSHwiki articles: Asbestos, Respirable Crystalline Silica

Visit the web section on work-related cancer

Learn more about the Roadmap on carcinogens

Legal safeguards

Everyone involved in managing dangerous substances in workplaces needs to be aware of the legislative framework covering dangerous substances in the EU.

OSH legislation is aimed at protecting workers from safety and health risks in general and of dangerous substances in the workplace (e.g. the Chemical Agents Directive, the Carcinogens Directive, and the directives on limit values). It requires employers to carry out a workplace risk assessment of all safety and health risks, including the risks from dangerous substances, and to set appropriate protection and prevention measures. Find summaries of the relevant EU legislation.

The aim is to ensure that risks are tackled at the source and to make collective measures — that is, measures that protect a group of workers in a systematic way — the first priority.

The REACH legislation and the CLP Regulation require chemical manufacturers and suppliers to ensure that standardised safety labels, hazard pictograms and safety data sheets are provided. These provide information on the properties of substances and the hazards associated with them, and guidance on storage, handling and risk prevention. Other regulations and guidelines cover specific aspects, such as manufacturing, supplying, transporting and labelling dangerous substances, and these are often relevant to the workplace too.

EU regulations on safety and health at work are incorporated into national legislation, but Member States are also entitled to include additional or stricter provisions for the protection of workers. It is therefore important that enterprises check the specific legislation in each relevant country.

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