ACGIH has published values of threshold limits for carcinogenic substances. These are airborne carcinogenic substances to which employees may be exposed in the course of their work. The concentrations are usually expressed in milligrams per cubic air meter or parts per million. Examples of threshold limits include: time weight average usually 8 hour workday and 40 hour work week, short time exposure limit with an average of 15 minutes, ceiling limit that should never be surpassed at any time of the day, and skin and eye prevention from exposure to carcinogens for employees especially in areas around male reproductive system, female reproductive system and fetal development according to the California list.
OSHA publishes threshold limit values that should be effective, but differs from ACGIH in that the TLVs are law enforced. The carcinogens are grouped as (A1) if they are human carcinogens or (A2) if they are suspected to be human carcinogens. Laws are enforced to protect the employees working under such conditions to which if the employer fails to meet, is punishable by law. For example, chemicals odor threshold in the range of which a normal person can detect an odor and RESP.
A carcinogen policy published by Edward J. Fairchild in 1976 addressed that no carcinogenic levels of exposure are detectable, but due to scientific advances they came in ways of risk management. Hence NIOSH adopted a new policy and recommended exposure limits for carcinogenic compound. The policy applies to workplaces dangers of carcinogens exposure. They also describe levels of exposure safe enough for different periods of employment, including exposure levels (but not specifically limited to them) at which no employee will be at risk.