As of 2021, how many different classifications of U.S. hazardous materials suits are currently in use?

With the COVID-19 pandemic, its variants, and other communicable diseases, a hazmat suit (hazardous materials suit) is a piece of personal protective equipment consisting of an impermeable whole body garment worn as protection against hazardous material, including solids, liquids and human contact.

Hazmat suits are also worn by firefighters, emergency medical technicians, paramedics, researchers, personnel responding to toxic spills, specialists cleaning up contaminated facilities, and workers in toxic environments.

In the U.S. there are 4 classifications of hazmat suits identified as Levels A, B, C and D.

Level A is the highest level of protection against vapors, gases, mists, and particles. The protective equipment consists of a fully encapsulated chemical entry suit with a full-face piece, self-contained breathing apparatus (SCBA). Boots are also required with steel toes and shanks on the outside of the suit with specially selected chemical-resistant gloves.

Level B protection is not vapor-protective. As with Level A, two-way radio communication is required.

Level C differs from Level B in the area of equipment needed for respiratory protection. This level allows for the use of respiratory equipment other than SCBA, plus the suit does not offer protection needed in an oxygen deficient atmosphere.

Level D equipment does not protect the person from chemical exposure. It is only used when the person has no possibility of contact with chemicals.