 The American Conference of Governmental Industrial Hygienists (ACGIH) Committee on Physical Agents has established a threshold limit value (TLV) for UV-C exposure to avoid such skin and eye injuries among those most susceptible.For 254 nm UV, this TLV is 6 mJ/cm2 over an eight-hour period.The TLV function differs by wavelengths because of variable energy and potential for cell damage.