As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EN ROUTE CDG-SFO, FLIGHT CREW OXYGEN PRESSURE DECLINING AT RATE OF 20 PSI PER MINUTE. FLIGHT DIVERTED TO KEF. *S/D* ON ACCOMPLISHMENT OF LEAK CHECK, FOUND OXYGEN BLEED VALVE, (P/N 19820-1), LEAKING OUT AT THE EXHAUST PORT. VALVE WAS REPLACED WITH A NEW VALVE AND LEAK CHECK ACCOMPLISHED. NO FURTHER LEAKS WERE NOTED. VALVE SENT TO VENDOR FOR FAILURE ANALYSIS.