Substitution of dangerous chemicals

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Substitution of hazardous chemicals in the working environment is a method to a fundamental and continued improvement of occupational health by selection and development of alternative technical processes using less hazardous chemicals or no chemicals at all. In a substitution the chemicals in the final situation must be potentially less hazardous than in the initial situation, and the difference should be as great as possible. It is especially important to avoid chemicals with long-term effects of a carcinogenic, reprotoxic, allergenic, or neurotoxic nature. Less hazardous chemicals are not necessarily harmless, so the traditional preventive measures may still have to be used, but the substitution has reduced the level of hazards. Successful substitution may, however, require technical and organizational changes. Substitution cuts the cycle of hazardous chemicals – also in the environment. Substitution of hazardous chemicals is one way to clean technology. The main problem is to get these less hazardous technical possibilities realized to a full extent in the foreseeable future.

Method[edit]

A systematic process-based method, which is based on a process engineering point of view, is useful both on branch and company level and includes:

  1. listing the chemical products,
  2. obtaining information on their composition,
  3. developing data sheets,
  4. process analysis,
  5. assessing the risk, and
  6. proposing substitutes.

Listing the chemical products is the first step in a systematic approach to improve occupational health. The method proposes to use a form should be used for each chemical product, and to perform surveys of production lines, processes and process steps so that the chemical products can be referred thereto. Listing on a company level will normally result in a purge of chemical products, because it is often found that some products are used in places other than those intended, that products are no longer used and that there is more than one product for a specific use.

The data sheets has a matrix which, when filled in, provides a picture of the present knowledge of the long-term effects:

Damage to health Under suspicion for damage to health Probably no damage to health Conflicting information No documentation
Carcinogenic
Reprotoxic
Allergenic
Neurotoxic
Other effects

The matrix specifies detailed the knowledge of the long-term effects. The most common result is “No documentation”. In future we can hope to get substances separated in “damage to health” and “probably no damage to health”. In the work with substitution it is important to distinguish between “Probably no damage to health” and “No documentation”. The matrix could be useful for producers when they formulate products and want to avoid chemicals with long-term effects. In workshops the matrix could be used to control that there is sufficient information on available data sheets.

The process analysis is based on visits to plants and exhibitions and on studies of the relevant literature of the process in question. The process analysis comprises: the use of the process, the place of the process in a production line, subdivision into process steps, the level of technology, description of equipment, and the chemistry involved.

The assessment of the risk for processes is based on information on data sheets, workplace measurements of exposure, and epidemiological surveys of occupational diseases. The risk to humans is “small” if it is probable that there are no long-term effects, the exposure is lower than the threshold limit value (TLV), and there are no indications of diseases, symptoms or nuisances.

If the risk is not “small”, the possibilities for substitution should be looked into. The process analysis has normally already generated alternatives for which are making an assessment similar to the initial process. Then it is possible to compare and decide whether the alternative is a good substitution. Substitution should be envisioned in connection with the whole production line – the total exposure must be reduced. By the substitution other effects in the working environment than the chemical hazards and the effects on the environment should also be considered. The proposed substitute should be tested in workshops for technical applicability, or existing technical experience in workshops should be collected.

This process-based method is especially suitable in following cases:

  • processes for which little knowledge of chemical factors of occupational exists, because these will be elucidated systematically and dealt with.
  • processes with many chemical products, because this opens up several possibilities for substitution.
  • processes with many types of design.
  • processes for which alternative processes exist
  • selection and development of new technology, because potential hazards due to chemicals are systematically worked through.

Results[edit]

Substitution can be on different levels such as using

  1. less hazardous chemicals in the same process, e.g.
    1. For construction paints: from organic solvents to waterbased paints,
    2. In printing industry for cleaning of offset printing machines: from organic solvents to products based on esters of vegetable oils,
  2. a new design of the process, e.g.
    1. In metal degreasing: from vapour degreasing with trichloroethylene to high pressure hosing with hot alkaline solution in a closed system,
    2. In brazing: from fluxes containing boron and fluor compounds to use of a furnace with reducing atmosphere,
  3. a new process, e.g.
    1. Removal of old paint: from a mixture of dichloromethane and methanol to blasting with steel sand in a closed system.
    2. From bonding with adhesives to a new design of items locking them mechanically together, mutually,
  4. avoid the use of the process, e.g.
    1. Avoiding electroplating with nickel only applied for cosmetic reasons.
    2. Furniture of wood: from lacquer with organic solvents to no surface treatment especially used for furniture of quality.
  5. avoid to produce products involving hazardous processes.

For more examples of substitution see External links and References.

References[edit]

  • Sørensen, F. and Styhr Petersen, H.J. (1995) “Substitution of hazardous chemicals and the Danish experience.” Occupational Hygiene, 1, 261-278 (a review article)
  • Sørensen, F. and Styhr Petersen, H.J. (1988). “Substitution of dangerous chemicals by a process-based method,” Staub – Reinhaltung der Luft, 48, 469-472
  • Sørensen, F. and Styhr Petersen, H.J. (1991). “A process-based method for substitution of hazardous chemicals and its application to metal degreasing”, Journal of Hazardous Waste & Hazardous Materials, 8, no 1, 69-84
  • Sørensen, F. and Styhr Petersen, H.J. (1992). “Substitution of organic solvents”. Staub – Reinhaltung der Luft, 52, 113-118
  • Sørensen, F. and Styhr Petersen, H.J. (1993). “Substitution of organic solvents and hazardous binders by bonding with adhesives in the manufacture of fabricated metal products, machinery and equipment”. Staub – Reinhaltung der Luft, 53, 251-254
  • Sørensen, F. and Styhr Petersen, H.J. (1994) “Formulation and Recycling of Water-Based Degreasing Agents: Effects on Occupational Health and Environmental Protection”. Journal of Hazardous Waste & Hazardous Materials, 11, no 3, 361-370
  • Sørensen, F. and Styhr Petersen, H.J. (1993). “Vapour Phase Soldering and Removal of Flux Residues after Soldering in the Electronics Industry: Substitution of Organic Solvents”. Hybrid Circuits, 30, 31-32
  • Sørensen, F. and Styhr Petersen, H.J. (1992). “Rapeseed oil is an alternative fluid. American Machinist”, 9,15-17
  • Sørensen, F. and Styhr Petersen, H.J. (1994). “Nonsolvent Based Lubrication of Machine Elements”. Lubrication Engineering, 50, no 1, 63-64.

External links[edit]