This directory contains files for the GRI-Mech kinetics mechanisms for natural gas combustion chemistry, sponsored by the Gas Research Institute. Two mechanisms are currently available: GRI-Mech 1.2 for high temperature natural gas combustion GRI-Mech 2.11 adds NO formation and reburning kinetics Separate readme files README12.DAT and README211.DAT are available. Mechanism files are GRIMECH12.DAT and GRIMECH211.DAT. Thermodynamics polynomials are in THERMO211.DAT. Transport coefficients are in TRANSPORT.DAT. Some Chemkin bugs are reported in BUGFIX.DAT. On Nov. 4, 1995, GRI-Mech 2.1 was replaced by GRI-Mech 2.11 to correct two errors. Files have been revised and renamed.