Engineered nanoparticles: "It remains impossible to quantify the risks for workers" (8/10)
An initial assessment of the state of scientific knowledge about the occupational health and safety aspects (OHS) related to synthetic nanoparticles (NP) was published by the IRSST in 2006, and covered the scientific literature until the end of 2004. What was found was that OHS knowledge was very fragmentary but that research in this field was rapidly growing. This current document aims to assess the state of current knowledge in this field and summarizes the data available until early 2010.
Overall, what emerges is that NP remain an important source of concern in OHS. The literature gives us very little information specific to NP relating to their physical hazards like fires or explosions.
As for health hazards, many toxicological studies on different substances have demonstrated toxic effects on various organs. It is found that in general, an NP will normally be more toxic than the same chemical substance of larger dimensions, but it is currently impossible to determine which measuring parameter for exposure is best correlated with the measured effects.
The evaluation of occupational exposure must therefore address a series of different parameters, and the exposure data available are relatively rare. It should also be noted that at the present time, attention is particularly focused on carbon nanotubes (CNT), which seem to show, in different animal studies, toxicity similar to that of asbestos and consequently causing great concern in the international scientific community, mainly relating to prevention.
In a context of incomplete data for the majority of nanometric substances, it remains impossible to quantify the risks for workers in the majority of situations because the toxicity of the products, the level of dust contamination of workplaces, or their potential to cause fires or explosions remain not extensively documented or totally undocumented. Nevertheless, the majority of the means of exposure control for ultrafine particles should be effective against NP and much research is currently being carried out to confirm this.
In a context of uncertainty about the risks, and with an increasing number of potentially exposed workers, the current report paints a big picture of the OHS knowledge currently available in the NP field. In the absence of specific standards, a preventive and even a precautionary approach are recommended, and a review of the available means for minimizing worker exposure is presented.