3.1 General Principles for Designing Safer chemicals Two main ways to avoid Hazard and Toxicity 1: make it not possible to enter the body 2: make it not possible to affect the bio chemical and physiological processes(生物化学 和生理过程) hazardously. Direct hazard: to human beings, to environment Indirect hazard to human beings, to environment 四大学化学学院 2002年7月26日四川大学化学学院 2002年7月26日 2 3.1 General Principles for Designing Safer Chemicals ◼ Two main ways to avoid Hazard and Toxicity ◼ 1：make it not possible to enter the body, ◼ 2：make it not possible to affect the bio￾chemical and physiological processes(生物化学 和生理过程)hazardously. ◼ Direct hazard：to human beings, to environment ◼ Indirect hazard： ◼ to human beings, to environment