Chemical - chemicals that may be stored in pipes, tanks, and/or held under pressure.
Pneumatic - trash compactors, compressors, lifting equipment.
Thermal - extreme heat from heating elements or furnaces or cold energy from refrigeration units or compressed gases.
Electric - electrical equipment which is either wired or operated by cord and plug.
Mechanical - stored energy in rotating or moving parts or conveyor belts.
Other - such as x-ray, radiation, laser, microwave, radio frequency, or others.
Lockout devices are designed to keep the equipment from being turned on or to keep the energy source from being released.