The 200,000-Hour Base Is Not an International Standard: Origins, Misapplication and Evidence from Saudi Arabia and the Gulf

Injury rates normalised to 200,000 hours, such as the Total Recordable Incident Rate (TRIR), are widely treated as an international safety metric. This paper argues that the 200,000-hour base is a US national convention. Introduced with OSHA’s recordkeeping regulations in 1971, it represents 100 full-time workers at 40 hours a week for 50 weeks: the US standard working week under the Fair Labor Standards Act and a typical US working year. It has not been revised since. The international standard, defined by the International Labour Organization in 1998, uses 1,000,000 hours. The arithmetic of the formula is valid anywhere when actual hours are used. The problems arise when the US convention is exported without its context: exposure hours are estimated from headcount using a 2,000-hour year, rates are read as “per 100 workers,” and benchmarks mix different bases. In Saudi Arabia, where the legal working week is 48 hours and contractor sites often work 60–72 hours, estimated exposure can distort reported rates by 18–80%. Gulf industry shows no common practice: Saudi Aramco and SABIC report per 200,000 hours, ADNOC per million hours, and Saudi national statistics per 100,000 workers. Drawing on published evidence, the paper also shows that site-level rates are statistically unreliable, vulnerable to under-reporting and unrelated to fatality risk. It recommends keeping national differences in the hours rather than the constant, adding explanatory notes to OSHA guidance and certification content, and adopting a national, ILO-aligned reporting guideline in Saudi Arabia.