Introduction During their work shift, workers may be exposed to chemicals. In France, when a risk is identified to a workplace, atmospheric concentrations must be measured to determine worker’s exposure.

Methods The regulatory authorities in France have published a list of Occupational Exposure Limits Values (OELV) concerning 143 substances and guidelines to establish the sampling strategy, including statistical methods to determine when exposure exceeds its OELV. This approach is similar to the one that will soon be published in the European standard EN689.

Result The good practices for the sampling strategy promoted by INRS begin with a comprehensive chemical risk assessment. The similar exposure groups and the number of samples to be collected have to be determined, as well as the organisation of the sampling in the company: this is the sampling strategy. Afterwards, the statistical assessment can be performed if enough data is collected. In this situation, several computing methods can be applied, these are implemented in the open source Expostats library. To assist hygienists in designing strategies and assessing exposure, INRS launches a new version of Altrex, a web-based software that use Expostats.

Discussion The old version of Altrex required important update to conform to current good practices promoted by INRS. The good practices proposed and the assistance provided with Altrex can help industrial hygienists in performing a correct risk assessment and thus implementing appropriate risk management measures.