Although most people know that elemental mercury and mercury salts are virulent poisons, it is commonly presumed that the danger is from oral ingestion. However, mercury is extremely volatile and the vapors are readily absorbed through the respiratory tract or unbroken skin.
Mercury acts as a cumulative poison because the rate of elimination by body functions is low.
If mercury is spilled in a gage house or field vehicle, concentrations hundreds of times greater than the maximum allowable can be attained. The saturation vapor concentration increases with increasing temperature. At 60 degrees C, the maximum allowable concentration is exceeded by nearly 25,000 times. Thus, mercury must be handled with the utmost regard for airborne contamination. Another use of elemental mercury by WRD is in thermometers, and to a lesser extent in mercury-filled barometers.