Recently much of the textile workforce in the United States has changed from an 8 hour work day to 12 hour work days. The pattern of work has shifted from a 40 hour work week to a 36 or 48 hour workweek (3 or 4 days at 12 hour shifts). The Cotton Dust Standard is based on an 8 hour time weighted average of 0.2 mg/m³ for a 40 hour workweek. Some enforcement agencies have indicated that for those working 12 hour shifts, either cotton dust levels must be reduced from 0.2 to 0.133 mg/m³ or respirators should be used for a portion of the shift. The basis for the dust level adjustment is Haber's law which states that toxicity or effect (EL) is a direct function of time (t) and concentration (C ): EL = t C. This paper reviews the use of Haber's law for adjusting exposure levels for novel workshifts in the cotton industry, the influence of shiftwork on pulmonary function measures, and the strategy of partial shift use of respirators as a compliance mechanism for novel workshifts.