305. Special measures: Unless special precautionary measures are taken by the employer, no worker may enter or be present in an enclosed area when a qualified person has detected the presence of a contaminant, other than those referred to under section 300 and whose concentration requires the taking of such measures.
These measures include training devised by a qualified person and dealing with methods and techniques that shall be employed by the worker to carry out his work safely in this enclosed area. They can also provide, where necessary, for the use of equipment that is appropriate for this type of work as well as the other personal and collective protective means and equipment that the worker must use.