BIOLOG is a bibliographic pointer file of microbial biodegradation/toxicity data. Each record contains a Chemical Abstract Services Registry Number (9 bytes), a string of data codes (total of 10 bytes) and a reference number (6 bytes). The string of data codes is divided into: (1) an indication of biodegradation (B) or microbial toxicity (T) data (1 byte); (2) oxygen condition- aerobic (AE) or anaerobic (AN) (2 bytes); (3) culture type-pure enzyme (PE), pure culture (PC), mixed culture (MC), or cell-free extract (CF) (2 bytes); (4) source of micro-organism- soil (SOI), sediment (SED), sewage (SEW) fresh water (WAF), marine water (WAM) or other (OTH) (3 bytes); (5) whether the pathway of degradation was (R) or was not (blank) studied (1 byte); and (6) data source- DATALOG (D) or various files from Dr. Martin Alexander at Cornell University (H, M, G, A, or P) (1 byte). The file should be used with CASLST (in order to link the chemical name and formula) and XREF (in order to link the full reference citation).