OHSAS stands for Ocupational Health & Safety Advisory Services.OHSAS 18001 (officially 'BS OHSAS 18001:2007') As ISO [International Organisation for Standards ]did not develop a health & safety management system, it was the British Standards Institute BSI who developed OHSAS 18000 in cooperation with ISO and international certification bodies.OHSAS 18001 (officially 'BS OHSAS 18001:2007')occupational health and safety management systems help all kinds of organizations put in place demonstrably sound occupational health and safety performance.