This will give you a clearer understanding of what is considered a confined space and the regulations on what is required to enter a confined space. This will include who can enter, who has to stay outside, monitoring the space, and all the recording required during the operation. The following are some of the hazards discussed in the module; engulfment, from flooding, from particulates, etc., oxygen deficiency (19.5% or less) or oxygen enrichment (23.5% or greater), flammable gases or vapors that may be present, hence the requirement for atmospheric testing, combustible dusts (grain silos), toxic substances (chemical tanks) and physical hazards (internal machinery inside the confined space, i.e. impellers, etc. The rules for confined space entry are very specific and have to be followed as set out in the regulations.