The topic of chemical oxidative degradation in rotational molded polyethylene (high-density cross-linked) chemical (sodium hypochlorite) storage tanks is an industry problem that ranks at the top of current business issues for manufacturers of chemical storage tanks. The degradation of these tanks not only compromises the physical and mechanical properties of the tank material, but reduces the life expectancy of the tank, eventually resulting in catastrophic tank failure. Premature tank failure comes at a hefty cost. The reputation of the manufacturer is questioned often resulting in immediate loss of customer satisfaction and future business. The leaking of the chemical from the failed tank serves as a liable environmental hazard that jeopardizes the safety and welfare of its surroundings – people and environment. And the associated manufacturer of the failed tank is almost certainly responsible for the repair or replacement of the tank. All these associated problems and many more related to chemical tank failure cost this relatively small industry millions of dollars annually. The need to determine the failure mechanisms of these tanks is critically important. Such an understanding will provide industry with useful knowledge that will open the door for improvements in tank performance. There is no question that a deeper understanding of failure mechanisms will improve a tank manufacturer's reputation, increase business sales, and assure environmental safety. The addition of this knowledge will also instill consumer confidence in an industry that is considered to lack refined manufacturing processes and proven quality controls. Such advancements are keys to making rotational molding a cutting-edge, technology-driven process that prepares industry for future growth and development. The purpose of this research is to provide tested empirical data and proven expert analysis that can be utilized by companies in understanding the failure mechanisms of these tanks. The information regarding this topic was collected from various tank samples taken from Poly Processing, a leading manufacturer of rotationally molded polyethylene chemical storage tanks and producer of the examined samples, and Odyssey Manufacturing, a manufacturer of bulk sodium hypochlorite and the end user of the examined samples. In the final chapter of this research, a summary is presented of the important findings regarding the purpose of the thesis study.