This study investigates the fabrication and use of polyethylene resin and fiberglass to encapsulate and secure containerized hazardous wastes. Laboratory-scale encapsulates of composite structure were made from powdered, high-density polyethylene (HDPE) and epoxy-resin-wetted fiberglass. Methods are described for fabricating encapsulates with seamless polyethylene walls backed by fiberglass, and a demonstration is given of their high performance under severe leaching and mechanical stresses. The objective of the study was to develop a method for securing hazardous wastes held either in small, corroding containers or in large ones such as 55-gal drums. The drums would be encapsulated on an as-is basis (i.e., their contents would not be emptied). Encapsulation would make them safe to transport and to deposit within a final disposal site such as a landfill. This study is a companion to two other documents investigating the use of plastics for the encapsulation of corroding containers of hazardous wastes: Securing Containerized Hazardous Wastes with Welded Polyethylene Encapsulates (PB81-231292) and Securing Containerized Hazardous Wastes by Encapsulation with Spray-on/Brush-on Resins.