Regulations to Prevent Toxication by Organic Solvent is one of the important decrees that control the chemical hazards in occupational site. It was originally adapted from Japan. In this regulation, the provisions related to the categorization of organic solvents, the tolerant consumption amount, and the requirement of displaced ventilation were found to be based on saturation vapor pressure model, zero ventilation model, and box model. These quantitative exposure assessment models have been accepted by AIHA as primary methods to evaluate the occupational exposure hazard. No matter which model to be used, a permitted exposure level for each concerned organic solvent must be determined at first. According to saturation vapor pressure model, the control facilities can be determined by the ratio of saturation vapor pressure of a concerned organic solvent to its permitted exposure level. In Regulations to Prevent Toxication by Organic Solvent, the first kind organic solvents are required to be controlled by a closure or local exhaust system. The above ratio of this kind of organic solvents was found to be above 1000. Zero ventilation model estimates the concentration of a chemical diluted by the existing air in a room. This model can determine the permitted consumption amount of an organic solvent. Box model estimates the steady-state concentration of an organic solvent under a given consumption and ventilation rates. In above Regulation, the permitted consumption amount and required ventilation of the first and second kind organic solvents are close to the median values calculated from those of each kind. To deal with a variety of chemicals, a domestic Stipulation on Hazardous Chemicals Assessment and Categorization Management was drawn up. This stipulate regards the quantitative models as the acceptable methods to assess the exposure in occupational sites. This study compared and retrospected above Regulations and related quantitative exposure assessment models. The results are helpful for an employer to establish his own measure to control a variety of chemicals by following a similar logic presented in this study under the Stipulation.