Both BP and Transocean bear responsibility for the 2010 Deepwater Horizon oil disaster in the Gulf of Mexico, federal investigators said. The Chemical Safety Board said gaps in programs for managing safety at offshore wells included a failure to assess the potential risks while drilling the Macondo well in the gulf, the Houston Chronicle reported Monday. \"BP and Transocean had multiple safety management system deficiencies that contributed to the Macondo incident,\" the board said in its report. The board recommended federal regulators step up monitoring of offshore incidents that may serve as early warning signs of potentially catastrophic accidents. The safety board is scheduled to detail preliminary findings Tuesday in Houston. Its investigation is the last major investigation into what went wrong when oil and explosive gas surged from of the Macondo well April 20, 2010, and ignited aboard the Deepwater Horizon rig, killing 11 workers and seriously injuring 17 others, as well letting loose an oil spill that lasted for months and dumped an estimated 4.9 million barrels of oil into the gulf. Among other things, the report says BP didn\'t assess the potential accidents and risks while drilling the well 41 miles off Louisiana and a mile under the Gulf surface. Similarly, Transocean\'s safety assessment of the Deepwater Horizon in 2004 emphasized personal safety issues but didn\'t include recommendations to address major accident risks, the report said.