Abstract
Today more than 300,000 persons in the U.S. work unusually long shifts (longer than eight hours per day) during which they are exposed to airborne toxicants. This paper reviews EXXON's experience in managing the various potential occupational health problems associated with such work schedules. A review of mathematical approaches to modifying exposure limits for such shifts is included; special emphasis is placed on the potential role of circadian rhythm effects as they serve to affect the physiological adjustment of workers to these schedules. A listing of the kinds of physical ailments which have been associated with unusual work schedules is included also. A fairly thorough list of references accompanies the text.