Document makes revisions to procedural rules governing practice before the Occupational Safety and Health Review Commission. The primary revision removes language that discouraged oral argument before the Commission and sets forth rules for the conduct of such argument. The document also amends the Commission''s procedural rules to require that show cause orders be served by certified mail, return receipt requested; and requires corporate employers to identify all corporate affiliations at the onset of Commission proceedings. Effective Date: 6/ 4/90. Contact: Earl Ohman, Jr., (202)634-4015.