(a) section Ala, Alb or A2 of Appendix A of the Threshold Limit Values for Chemical Substances and Physical Agents in the Work Environment, published by the ACGIH, as amended from time to time; or
a) soit à la section A1a, A1b ou A2 de l’annexe A de la publication de l’ACGIH intitulée Threshold Limit Values for Chemical Substances and Physical Agents in the Work Environment, avec ses modifications successives;