24hour vs 40hour HAZWOPER
So, what's the big difference between the two other than the amount of time to complete each one? The 24-hour training is aimed primarily at individuals who will work at contaminated sites and conduct work tasks that do not expose them to hazardous substances at or above the Permissible Exposure Limits (PEL's). The PEL's are established by the Occupational Safety and Health Administration (OSHA) in 29 CFR 1910.1000 in the "Z Tables". The Z Tables regulate the amount of Air Contaminants. The regulatory limit cannot be exceeded without proper engineering controls in place or Personal Protective Equipment (PPE) for employees. 40 hour HAZWOPER certified individuals can be exposed to hazardous substances that exceed these limits but they must wear the appropriate PPE. While the Z Tables largely focus on respiratory protection, there are special notations for skin absorptions for certain hazardous substances.
Four Levels of PPE
There are four levels of PPE - Level A thru Level D. In general, Level A involves worst-case conditions and maximum risk. The environment has the potential to be immediately dangerous to life and health (IDLH). Pressure-demand self-contained breathing apparatus and totally encapsulated chemical resistant suits are required. Level D involves emergency escape respiratory protection and minimum eye and skin protection.
For individuals who conduct ground-water sampling, investigations, site visits, etc., they will more than likely meet OSHA regulations by completing the 24-hour HAZWOPER training. For people who are engaged in remedial operations of contaminated sites it would be better for them to complete the 40 hour HAZWOPER training to ensure OSHA compliance. There are upgrading and downgrading of PPE considerations as well as potential changing site conditions.