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PRIO – A tool for Risk Reduction of Chemicals

Risk analysis

Handling chemicals can pose risks to humans and the environment. The legislation is very clear in respect of the performing and documentation of risk analysis. 

The work environment legislation, operator's control and knowledge requirements in the Environmental Code, each in its own way makes the requirement that one should define the risks of chemical substances in products and processes.

The risks that are present and what exposure is allowed are determined by the properties of the hazardous substance and the method of handling. There are a number of different methods of assessing the risks associated with a chemical substance. Here the company must itself judge which model has the right level of ambition and meets the external and internal requirements of the risk analysis. Many companies choose to work with a risk value. The risk value depends for example on the constituent substances' hazard, exposure time, exposure potential, amounts and the technical protective measures.

Risk value = Hazard x Amount x Exposure

This formula is not to be regarded as a complete risk analysis, but can provide guidance. When assessing the results of risk analysis this should be taken into account, and it is advisable to always check that the results are reasonable before proceeding further to implement measures. An example is given below of a method that can be used for risk analysis[1]. The safety data sheet is an important source of information for a risk analysis.


The hazard parameter is determined by the intrinsic properties of the substance. This may for example be a case of health hazard when inhaled, allergy, being carcinogenic, inflammability, harmful to the environment or the risk of reactions with other substances. Depending on the type of hazardous properties inherent in a substance it can be assigned a number of different points during the risk analysis. The company itself must decide how properties will be assigned points and the PRIO tool can be used as a basis for the work. Prioritisation has been done in PRIO by dividing the risk phrases for substances into "substances due to be phased out" and "substances that have priority in risk reduction". It is proposed therefore that the risk value is used for internal comparisons within each of the prioritisation groups in PRIO.


The next parameter in the calculation of the risk value is the amount. The greater the amounts that are used, the greater the risk, in many cases. If you want to work with risk values, from the amounts used by the company various amount intervals can be created and then awarded points. A large volume of a substance therefore leads to more points in the model. In order to obtain a relevant relationship in the amounts handled, each company itself must decide which amount intervals are to be worked with in the risk model. When then looking at the combined risk value for a substance, it is important to be aware that a substance with particularly hazardous properties may only need to be in small amounts to account for a large risk.


The final parameter in the calculation is concerned with assessing to what extent people and the environment are exposed as a result of a certain kind of handling. Environmental exposure includes for example the ground, air, surface water and sewage treatment plants. The size of the exposure is determined by a number of different factors. Exposure can be assigned points, in the same way as hazard and amount.

Exposure can involve both production processes and articles
In the first place one naturally thinks that it is exposure to chemicals in the production process that must be minimised. However many chemicals follow along with the company products (articles) and can have effects on health and the environment far away from the factory. It can be important to keep both aspects in mind when assessing exposure.

Production processes

The are a number of factors to take into account when assessing exposure, and you must decide yourself at what level of detail they are to be considered. The table lists factors which are important when assessing exposure in connection with production processes.

Factor Examples of questions concerning exposure
  • Is the chemical used in a closed or open system?
  • Is there a risk of leakage?
  • Is there a risk of exposure in the case of an accident?
  • Is there protective or clean-up equipment and is it used?
Exposure time
  • How often are staff exposed? (occasionally, daily for more than x hours per day, etcetera)
Exposure potential
  • How much of the substance ends up in inhaled air or comes into contact with the skin or eyes of the staff?
  • How do the physical properties of the substance affect the exposure? (Boiling point/vapour pressure and process temperatures are the most important parameters to determine the volatility of the substance and thereby what can enter the air).
  • Does spreading occur by means of dust particles (grinding, abrasion, etcetera)?
  • Are there occupational exposure limits for the substance?
User groups
  • Gender
  • Age
  • Health condition
  • Smokers / Non-smokers

Each company must itself decide how it will assign points for each different type of use, but in general one can say that use inside a completely closed system gives lower points, whereas direct exposure to the surroundings or to workers merits higher points. The use of products that are volatile or very prone to dust can also merit higher points.


The use of articles and the waste that arises causes a diffuse spread of chemicals in the surroundings. In the case of articles with a long life, one must view the exposure in the longer perspective. Such articles accumulate in society, which means that exposure can be extremely long-term. The following factors must be taken into account when assessing the exposure of chemical substances concerning articles.

 Factor Examples of questions concerning exposure
Emissions potential
  • Which physical properties do the chemicals have, and how do they affect the exposure? (The emissions potential is affected by the physical and chemical properties, such as vapour pressure, volatility and solubility, and if it is in powder form.)
  • How is the substance attached to the material? (The emissions potential is also affected by the structure of the material and the way the substance is bound to the material.) Some substances are very closely bound to the material, such as chrome in stainless steel. Plastic additives on the other hand are often less closely bound and may be continuously emitted from the product.
Usage and user groups
  • How are the articles used?
  • Are there particularly sensitive groups of users?
  • Are they consumer articles or are they intended for professional use?
  • Can the appearance or function attract their use by children?
  • How does the life of the articles affect the exposure?
  • Are the articles used close to the body?
  • Are the articles used indoors or outdoors?
  • Is the exposure affected by ventilation and temperature?
  • Is there long term exposure of humans or the environment to the articles?
  • Will a considerable part of the articles material be given off as particles during its life (grinding, abrasion, etc.)?
Waste and waste disposal
  • How is the exposure to people and the environment affected by the way the articles are disposed of as waste?
  • Can substances come out into the surroundings during recycling or reclamation of the articles?
  • Can people and the environment be exposed to substances when the articles are dismantled?
  • Can recycling of the material lead to exposure to people and the environment?
  • Are the components labelled with their content of particularly hazardous substances?
  • Are there manuals describing dismantling?
  • Can dumped or burned goods cause the release of substances?
  • Will the goods or material of which it is made remain in the environment after use (buried cables, paint flecks, car tyre particles, etc.)?

The risk value provides a basis for decisions on what measures to take

The above questions can be of assistance when working on a risk analysis, and should give an overview of possible risks. The risk value model can be seen as a guide to the ranking of risks and prioritisation of preventive measures. The end product can be that chemicals are sorted into a few risk categories, such as "low risk", "acceptable risk", "medium risk" and "high risk". There may also arise situations where the basis for a risk analysis is so incomplete that the risk requires further investigation. With a risk analysis as a foundation, the next step is to decide on suitable protection measures. Here there may be technical, production or financial circumstances and limitations that must be taken into account Examples of measures may be:

  • Continued use of the product or a decision that a safer alternative shall be sought.
  • Which working methods are to be used and which location is to be chosen.
  • Which protective measures shall be taken and what instructions are to be given to the workers.
  • What accident readiness and procedures for emergency readiness shall apply.
  • What information about hazardous substances shall accompany the product to the customer.

The risk analysis should be documented, and appropriate managers and employees should have access to the documentation.

 [1] The method is based on the method presented in the Chemicals Guidance Manual, Copenhagen. COWI 2005

Links to web sites that may be useful when working with risk analyses

  • Arbetsmiljöverket
    Apart from the legislation, here among other things are check lists for risk assessment of chemicals and company examples of how risk assessment can be performed.
  • Naturvårdsverket
    Regulations (1998:901) concerning operator's control and associated general advice (NFS 2001:2)
  • Prevent
    Here you can order the Chemistry thermometer (only in Swedish), which is an aid to assessing chemical risks in the working environment
  • The Chemistry Guide (only in Swedish)
    The Chemistry Guide helps you at your workplace to find out which legal requirements apply to your work environment, and also advises how to continue working to minimise risks.