ed by introducing the definition of risk, which means the threat of damage to environmental resources, human health, and or the occurrence of a particular hazard. The process of estimating the environmental resources or human health affected adversely under hazardous conditions is called risk assessment. Risk assessments are made every day; therefore, we have to understand why risk assessment is important to life cycle assessments. To consider the raw materials we have to use and make them into products, and consider the energy and emission, and the pollution factors when we think about life cycle analysis, As a result, doing a life cycle analysis to decide whether to reduce the energy, or to reduce the number of raw materials, or to reduce potential pollution comes from the point of an environmental view. And another way is compilation and evaluation of the inputs, outputs and the potential environmental impacts of a produce system throughout its life cycle analysis.
There are two types of risks: natural and man-made. CO2, SO4, CH4, O3 are natural risk types. Man-made risks, such as oil spills into water resources, waste plant disposal into environment, coal electricity generate plant emits the CO2 into air, artificial chemical ingredients added into food, pesticide for agricultural process, and chemical component in products, such as, Bisphenol A is a chemicals added in the production of polycarbonate plastics, such as water, food container. Bisphenol A accounts for the majority of human exposure. First, Bisphenol A is widespeard, which has potentially adverse effects on human health. There has been tests already done by CDC which found out that detectable levels of Bisphenol A in 935 of 2571 urine samples from a sensitive subpopulation of children 6 years and older. This is especially bad because Bisphenol A can leach into food through human daily diet, and long term use can effect newborns. Also many studies suggest that children are more sensitive to