More and more chemicals and products on the market contain nanoparticles. Therefore, it is necessary to bear in mind any possible harmful affects on the working environment.
It is assumed that exposure and the risk of exposure from ultrafine particles will be increasingly important in the production/use of new products.
When particles are so small that they get down into the nano area, they can change character and have different technical properties than larger particles of the same chemical substance.
For example, gold in jewellery is harmless because gold is a noble metal and therefore inactive but gold nanoparticles are highly reactive and therefore extremely good as catalysts.
The harmful properties of particles can also change and that will be important for health and safety in the production and use of new products.
Nanotechnology is a relatively new field and it is only now that we are starting to discover specific occupational health risks (hazards from exposure and to health).
However, there are some work processes in which nanoparticles are formed and which have been known for many years, such as welding and other high temperature heat treating processes.
Welding fumes contain nanoparticles of the welded material, electrodes and fluxes.
The National Research Centre for the Working Environment (NFA) conducts research into the significance of nanotechnology for occupational health and safety.
NFA's research and international studies show that nanoparticles are probably not only dangerous due to their size but that their shape, chemical composition, functionalisation and properties also play a major role.
Generally speaking, we lack good ways of assessing exposure to ultra fine particles and the properties that can be dangerous to health - that is what NFA is trying to do.
NFA has developed a ”Nanotool” in conjunction with the Danish Technological Institute. The ”Nanotool” is a catalogue of tools for systematically analysing and identifying hazards and exposure risks.
The Danish ”Nanotool” has been available since September 2010. The catalogue indicates situations in which handling particles can be critical and provides guidance on using safety data sheets and other sources of knowledge in health and safety operations.
Nano-materials exist as free particles in powder form, in aerosols, in liquids plus in granules and paste. The biggest work environmental risk is inhaling air-borne particles.
When working with nano-materials you have to draw up a risk assessment. Here, you must include the dangerous characteristics of the nano material. This can be hard, since there is no internationally fixed Treshold limit values (TLV) for nano materials.
But the American Institute for Occupational Safety and Health (NIOSH) has formulated some recommendations for the TLV for nano materials.
The recommendations set by the American institute are well below the fixed TLV for other substances such as Titanium dioxide (30 times lower) and carbon nanotubes (1000 times lower than the TLV for carbon black.
Apart from the risk assessment, you have to use the prevention principles, which include substitution, arrangement of the work place and technical prevention measure (for instance local extraction and encapsulating) and lastly personal protective equipment (PPE).
Earlier, there have been doubts about whether the personal protective equipment could protect against these very small particles. Now we know they can, but it is important that you as a minimum use respiratory equipment with P3-filters.
You should ask the following questions:
- How should work be done and is there the risk of skin contact or inhalation?
- Is the system leaky and are there any leaks?
- Could the job be done in a closed system or has local air extraction been installed?
- Is personal protective equipment required? Will repairs have to be done later which could lead to exposure (surface treatment with nanoparticles)?
You should be especially aware of nanomaterials that have strong catalytic properties, nanofibres and nanomaterials with nanotube structures, which are single large molecules consisting of carbon atoms arranged like tubes.
You should be especially concerned about the effects of carbon nanotubes since some of them appear to have asbestos-like properties.
What are nano materials?
Nanomaterials are very small particles with at least one dimension being between 0.1- 100 nanometres. That is 0.1 - 100 millionths of a millimetre.
Nanotechnology gives products new, enhanced technical properties, such as more wear-resistant, colour-fast paint, lubricants with better lubricating properties and less friction or surface treatments for materials that make cleaning either superfluous or reduce the need for it.
Nanotechnology is currently not specially regulated by the classification rules for chemicals and neither with respect to the concept of hazards.
However, products will often be dangerous because of other substances they contain. This is why you can generally obtain safety data sheets that describe the substances contained, including nanoparticles.
So we do need to make analogue conclusions according to what we know about the properties and content of normal-sized substances. But since we do not know the true danger, it is important to take precautions by minimizing the risk of exposure as much as possible.
Senior Occupational Health Consultant
Anne L. Ries
+45 3311 1833
+45 2961 8860
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