Current knowledge on nanomaterial toxicity is fairly limited. The risk prevention should rest mainly on the limitation of professional exposures (duration of exposure, number of exposed workers, exposure level,…). Depending on the risk evaluation, it will be important to define and put in place safe work practices, practices which will evolve according to the state of scientific knowledge. These secure practices, slightly different from recommended practices for activities exposing to dangerous chemical agents, must take into account the high capacity of nanomaterial persistence and diffusion into the workplace atmosphere.

The prevention procedure ordered by the labor code (article L 4121-2, law of 31 december 1991) is composed of 9 steps:

• avoid the risks,
• evaluating the risks which cannot be prevented.,
• combat risks at source,
• adapt work to man,
• consider the evaluation state of the technique,
• replace what is hazardous by what is not hazardous, or by what is less hazardous,
• plan risk prevention,
• take collective protection measures giving them priority over individual protection measures ,
• give appropriate instructions to the workers.