The WasteGuard? tray range helps reduce the risk of sharps injuries by incorporating simple to use trays and bring the WasteGuard? sharps container closer to the point of use. A polypropylene tray for use with the WasteGuard? com-plus or the WasteGuard? 1. The tray is designed to reduce the risk of sharps or needlestick injuries, 23% of which occur after use and before disposal.