1.1 This test method covers the determination of the degree and rate of aerobic biodegradation of synthetic plastic materials (including formulation additives that may be biodegradable) on exposure to activated-sewage sludge inoculum under laboratory conditions. 1.2 This test method is designed to index plastic materials that are more or less biodegradable relative to a standard in an aerobic environment. 1.3 This test method is designed to be applicable to all plastic materials that are not inhibitory to the bacteria present in the activated sewage sludge. 1.4 The values stated in SI units are to be regarded as the standard. 1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazards are given in Section 8.