in maintenance shops where vehicles are operated at fixed test or repair locations. When motor vehicles move within a
building (e.g. materials handling equipment operating in a warehouse), carbon monoxide concentrations may be kept
below the threshold limit value of 100 parts per million parts of air either by general dilution ventilation or by limiting the
number of vehicles being operated at one time. Control of such other types of operations as forging, heat-treating, and
proof-firing also must be accomplished by maintaining a balance, either naturally or mechanically, between generation
and removal or dilution of fuel combustion products.
3. Severity of exposure. Some typical operations wherein the carbon monoxide exposure and basis for its control
are common are described in the following table. These operations were evaluated during industrial hygiene surveys
made by personnel of the Army Environmental Health Laboratory and illustrate the severity of exposure which may occur
through improper control.