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Chemical Hazards
Dangerous Substances & Chemical Hazards

Dangerous substances are defined by the nature of the danger  they can cause. They can be for example, flammable, explosive, toxic and radioactive. Working procedures  should be constantly reviewed for whether there is a reason to use dangerous substances at work. If the same results can be achieved with non-dangerous  or less dangerous substances, they should be used instead.


Dangerous substances are defined by the danger  they can cause. The danger  may vary depending on the nature of the substances.

Substances can be:

  • Explosive
  • Flammable
  • Oxidising
  • Radioactive
  • Poisonous
  • Irritating
  • Corrosive
  • Environmentally polluting
  • Other kind of danger

The same substance can cause different dangers. For example, it can be both flammable and corrosive. Other type of danger means, for example, that the effects of the substances do not necessarily appear immediately, but over a longer period of time. For example, an employee exposed to a carcinogen may not experience symptoms until a few years or even decades later when they may have developed cancer, which may be due to the fact that they were exposed to carcinogens long time ago

Another example is normal air that is in a pressurized cylinder . In this case, the pressure is the danger, as the cylinder may explode in a fire, for example.

It is important to keep in mind that substances can enter the body in different ways, such as through the respiratory tract, skin or gastrointestinal tract. In the workplace, the risk is greatest with inhalation, then contact with skin, but seldom the way into the body is through the digestive tract.

It is also important to keep in mind that the condition of the substances is important. Harmless substances under normal conditions can be dangerous in other conditions such as hot water or grain dust, which can cause an explosion under certain conditions. Then two or more harmless or  nearly harmless substances can sometimes react together to form much more dangerous substances. Likewise, the same substance can  be in different states such as gas, liquid or solid, the nature of the danger depends on the state the substance is in

It should be borne in mind that working procedures  must be under constant revision  with regard to whether there is a reason to use dangerous  substances at work. If the same results can be achieved with non-hazardous or less hazardous materials, the less hazardous materials should generally be used.

Dangerous Substances

Dangerous  substances are defined by the danger they cause or may cause. To be considered dangerous , they must meet the requirements in the regulation on the classification, labeling and packaging of substances and compounds, or the so-called CLP regulation. It covers in detail the properties of substances that make them, for example, corrosive.

Radioactive substances are not covered by the regulation. Special laws, which are under the authority of the Icelandic Radiation Safety Authority, deal with the use and labeling of radioactive substances.


According to regulations, the packaging of dangerous  substances must be labelled  with hazard pictograms  that indicate the dangers posed by the substances, so-called GHS pictograms. They are discussed in more detail in the booklet Dangerous  Substances in the Workplace below.

In addition to  labeling  on  packaging, work areas where dangerous  substances are used must be marked with safety signs  This must be done in accordance with the rules on safety and health signs in the workplace.

Where dangerous substances are used,  safety data sheets must be available. Safety data sheets are information sheets in sixteen sections which deal with hazards, prevention, personal protective equipment and so on, that apply to the relevant substance.

Substance suppliers are required to deliver safety data sheets in Icelandic or English with their substances to buyers free of charge. Employers are responsible for familiarizing staff with the contents of the sheets. Further information on safety data sheets can be found on the Environment Agency’s website.

Toxic substances are substances that can cause acute poisoning, i.e. a small amount of the substance causes serious effects to humans or even death. These substances are labeled GHS 06 pictogram or with a skull and bones according to the CLP regulation, the regulation on classification, labeling and packaging of substances and compounds.

If toxic substances are used in the workplace, a special  permit from the AOSH is required.

Carcinogens are substances that are known, from experience or research, to cause cancer in humans or animals. These are usually long-term effects and it often takes years or decades for the consequences to emerge.

Nanomaterials are a rapidly growing class of substances. These are substances, either dangerous or not, which appear  in the form of small particles, 1-100 nm. The substances are used, for example, in surface treatment of surfaces, among other things, to facilitate disinfection.

Various studies suggest that substances may be more harmful in nano form than conventional forms.

Explosive substances are used to some extent in Iceland in the construction industry. In order to be allowed to buy and use explosives, a special permit from the police is required. Those that want to apply for such licence need to pass a course held by  the AOSH and  pass a practical exam certified  by a certified explosives validator.

Pesticides and herbicides  are substances that are used to eradicate pests or to fight plant diseases. These substances are not always classified as toxic, that is to say with the GHS 06 label.

To be able to buy and use pesticides at work, a permit from the Environment Agency of Iceland is required.

Storage of Substances

Substances labeled as dangerous must be stored safely in the workplace. The substances must be stored systematically in a locked storage area when not in use. Workplaces should keep a list of all dangerous substances, the list should be updated regularly as needed.

It is important to regularly go through  storage facilities and dispose of unused substances appropriately. If substances are forgotten in storage, they can create a special hazard. This is especially true of substances in plastic packaging. Plastic can become brittle over time and packaging can break. Substances may then leak out with the accompanying hazard.

Exposure Limits

Workplace exposure limits are in force, specified in the Regulation on exposure  limits and measures to reduce exposure at workplaces. The regulation specifies  a certain maximum concentration of substances that can be in the indoor air at workplaces, both based on an eight-hour working day (TWA) and fifteen-minute peaks (STEL)).

Employers must ensure that exposure to substances is below the specified limits.

Personal Protective Equipment

Personal protective equipment is, by nature, a third-tier prevention measure. This means that if the substance can not be removed (stop using it), precautions taken to avoid contact or ensure ventilation, personal protective equipment must be used.

Personal protective equipment can be gloves, protective clothing or respirators. It is important to use the correct personal protective equipment. Section eight of the safety data sheets which must accompany dangerous substances shall state how personal protective equipment is to be used when the substance in question is used.

Risk Assessment for Substances

In workplaces where dangerous  substances are used, a special risk assessment for substances must be carried out. The risk assessment is part of the company’s written plan for health and safety.

For support, an electronic tool can be used to identify substance hazards, which can be found below. This is a handy tool in multiple languages that can be used to find and reduce hazards associated with dangerous substances and chemical products in the workplace

Major Accident Prevention

A major accident is an uncontrolled scenario in the handling of substances such as a large leak, fire or explosion that poses a serious danger to humans and the environment.


Asbestos threads are very durable and can withstand very high temperatures. Asbestos was used in previous years as a fire retardant, thermal insulation and in various industries.

When working with asbestos, needles or filamentary asbestos dust are formed. This dust is harmful to health and its use is banned in the European Economic Area.