Ships of the desert. Camels were domesticated more than 3,000 years ago, and to this day, humans depend on them for transport across arid environments. They can easily carry an extra 200 pounds (90 kilograms) while walking 20 miles (32 kilometers) a day in the harsh desert.
Definition - What does Permissible Exposure Limit (PEL) mean? Permissible exposure limit (PEL) is the legal limit in the U.S. for maximum concentration of any chemical in the air to which a worker may be exposed continuously for eight hours without any danger to health and safety. PEL is established by the Occupational Safety and Health Administration (OSHA).
Below is some information on the major occupational exposure values. Permissible Exposure Limits (PELs): The Occupational Health and Safety Administration (OSHA) has set permissible exposure limits (PELs) on the amount or concentration of a substance in the air.ome of the PELs are listed as ceiling values â concentrations above which a worker should never be exposed, or short-term exposure limits (STELs) âaverage concentrations which should not be exceeded over a 15 minute time period. It is important to note that the PELs tend to be higher than other published values.