The UNECE commission issued the ADR (European Agreement concerning the international Carriage of dangerous Goods), which requires an exchange of plastic containers every 5 years from the date of their production (chapter 220.127.116.11). This is conductive to your safety, as the quality of many plastics may change due to the environmental conditions.
Check out the Containers for liquid Waste – compatible to the S.C.A.T. System here.
Download the original ADR document at the UNECE (United Nations Economic Commission for Europe) website