This study performed HAZOP, which is a qualitative risk assessment for the API(Active Pharmaceutical Ingredient) process, and aimed to check the solvent change, the root cause, to reduce the derived risk, select accident scenarios and high-risk solvent materials, and identify the substitution of low-risk solvent substances. This study conducted the Consequence Analysis(CA), which is a quantitative risk assessment, to determine the extent of damage in the event of a chemical accident caused by solvents. In addition, the ALOHA of the US Environmental Protection Agency was utilized, and the estimated impact scope was quantified as the cost of disaster loss, in addition to performing a cost-benefit analysis that considers safety and economic feasibility. The difference in the impact scope in the toxic exposure was relatively larger than the difference in the impact in the impact scope in the liquid fire of methanol and ethanol. Due to the characteristics of the pharmaceutical industry, it can be fatal to the human body if methanol remains in pharmaceuticals. Accordingly, it is recommended to use ethanol instead of methanol. This study examined solvent change and suggested a cost-benefit analysis that considers safety and economic feasibility. As a study on the intrinsic safety that replaces high-risk solvents with low-risk solvents, it is expected to contribute to the prevention of serious industrial accident caused by chemicals.