Fig. 1.
Hierarchy of controls. Adapted from the National Institute of Occupational Safety and Health (NIOSH) Hierarchy of Controls. Available at https://www.cdc.gov/niosh/topics/hierarchy/default.html. Not. PPE, personal protective equipment.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.