Cranfield Institute of TechnologyReports on the investigation undertaken into the effect of pressure on problems related to weld metal hydrogen levels encountered in SMAW. Emphasis has been placed on examining the influence of welding polarity and ambient humidity on weld metal hydrogen levels and weldment crack susceptibility where special attention has been paid to the first 100 ft. depth increment. Tests were also conducted to examine possibilities of simulating hyperbaric cracking with welds made in air under normal laboratory conditions.