I t's odd how many chemicals that you have used for years were always in question of biodegradability and proper disposal. However, suddenly without any change in formulation these same products have recently been self proclaimed "Environmentally friendly", "Biodegradable", "Drain Safe" or "E.P.A. approved." BIODEGRADABLE??? WHAT DOES IT REALLY MEAN? According to established ASTM (American Society of Testing Material) procedures the following is the definition of biodegradability: A minimum of 40% of the original sample has been decomposed to inert ingredients within twenty eight (28) days.