Johnson was a trained and certified heating, ventilation, and air-conditioning (HVAC) technician with a “universal” certification, the highest obtainable from the Environmental Protection Agency. He purchased R-22 refrigerant manufactured by American Standard and used it in maintaining and repairing air-conditioning units. Johnson sued American Standard for negligence, failure to warn, and design defect, alleging that the R-22 refrigerant exposed him to phosgene gas, causing him to develop pulmonary fibrosis. He admitted receiving and reading the Material Safety Data Sheets (MSDS) with each of his purchases of R-22 refrigerant, but claimed that he did not understand that heating the R-22 refrigerant could produce allegedly harmful phosgene exposures. Who should revail? Should the result be the same if Johnson did not purchase the R-22 refrigerant himself but was an employee of a company that would qualify as a sophisticated user? What public policies are implicated in cases such as this? [Johnson v. American Standard, Inc., 179 P.3d 904 (Cal. 2008).]