* Regulators say 44.1 pct oil, 1.5 bcf natgas output shut
* Producers start production restart, restaffing efforts
* NYMEX crude prices ease after Debby's move to Florida
By Kristen Hays
HOUSTON, June 25 (Reuters) - Some of the Gulf of Mexico's biggest oil and gas producers began to restart production and restaff evacuated platforms on Mo nday as Tropical Storm Debby slowly headed for the Florida panhandle, away from energy infrastructure in the basin.
Debby, the first named storm of 2012 to disrupt energy operations in the Gulf, temporarily idled nearly half of its oil output -- nearly double the amount shut on Sunday -- and more than a third of natural gas output as producers shut down operations and evacuated staff at installations in the storm's projected path.
The U.S. Bureau of Safety and Environmental Enforcement said on Monday that companies had shut in 44.1 percent, or 608,025 barrels per day of oil and 34.8 percent, or 1.5 billion cubic feet per day of gas was shut in. As restarts progress, those figures are expected to decline.
The Gulf accounts for about 20 percent of U.S. oil output and 6 percent of natural gas production.
BP Plc and Royal Dutch Shell, respectively the largest and third-largest oil producers in the Gulf, each said they were restarting output and restaffing platforms.
Anadarko Petroleum Corp, the largest gas producer in the Gulf, the company aimed to do the same for its four shut and evacuated platforms as weather conditions allowed. Anadarko's affected platforms include the natural gas-only Independence Hub, which can produce up to 1 billion cubic feet per day.
On Saturday, forecasters had expected Debby to turn west and cross the areas in the Gulf most populated with energy infrastructure, including most of BP and Shell's operations.
By Sunday, the storm's path turned northeast toward the Florida panhandle, away from oil and gas platforms. By Monday, Debby pounded Florida with heavy rain and was headed straight east toward the state's western coast.
Early gains in crude futures evaporated after Debby shifted course away from the Gulf production-rich areas.
BP said it would start with its westernmost operations and when restaffed, crews will restart production and drilling.
BP operates seven oil and gas platforms in the Gulf, including the world's largest, Thunder Horse, which is designed to produce up to 250,000 barrels per day of oil and 200 million cubic feet per day of natural gas.
Shell shut output at two of its seven operated platforms, Auger and Enchilada. The company also evacuated about 360 workers not directly involved in production.
"Re-start and ramp-up of the minimal subsea production shut-in has also begun today. By end of day Tuesday, we will be back to normal operations across the Gulf," Shell said.
BHP Billiton, which shut production at and fully evacuated its two platforms on Friday, said it was restaffing Monday and production was expected to resume on Tuesday.
Exxon Mobil Corp said the same about redeploying the portion of workers evacuated and restarting minimal output shut in, about 1,000 bpd of oil and 7 mmcfd of gas.
The Louisiana Offshore Oil Port (LOOP), the only U.S. port capable of offloading foreign crude from giant tankers, also said offloadings would resume after they were halted on Sunday because of rough weather.
Through that weather, the LOOP continued to deliver crude to refineries from underground storage caverns that can hold up to 67 million barrels, spokeswoman Barb Hesterman said.
Energy markets traditionally keep a close eye on storms passing through the region for output disruptions and possible supply squeezes.
The risk to markets because of Gulf storms has diminished slightly in recent years as the increased development of shale deposits fueled a boom in onshore oil and gas production.