HOUSTON (Reuters) – U.S. oil companies on Monday began restoring some of the nearly 74% of production that was shut at U.S. Gulf of Mexico platforms ahead of Hurricane Barry, the U.S. offshore drilling regulator said.

There were 1.3 million barrels per day (bpd) of oil production offline in the U.S.-regulated areas of the Gulf of Mexico on Monday, about 80,000 barrels fewer than on Sunday, according to the U.S. Bureau of Safety and Environmental Enforcement (BSEE).

Workers also were returning to the more than 280 production platforms that had been evacuated. It can take several days for full production to be resumed after a storm leaves the Gulf of Mexico.

Anadarko Petroleum Corp, BHP Group Ltd, Chevron Corp, Exxon Mobil Corp and Royal Dutch Shell Plc said on Monday they had begun returning staff to evacuated platforms and were in the process of restoring production operations.

“Redeployment and crew-change flights to some of our assets have begun now that weather conditions in the Gulf and onshore have improved,” said Shell spokeswoman Cynthia Babski. Three Shell platforms remained shut and a fourth had limited production on Monday, she added.

BP also has begun returning teams to evacuated facilities, said spokesman Jason Ryan. Production will resume after safety is assured, pipelines and receiving systems are working and regulatory approvals are in place, he said.

Barry came ashore in central Louisiana as a Category 1 hurricane with at least 74-mile-per-hour (119-kph) top sustained winds on Saturday. Late Monday, it was a post-tropical cyclone, and moving north at about 13 mph (20 kmh) into Missouri after dropping up to 4 inches (10 cm) of rain on Arkansas.

Following its arrival, offshore natural gas production in the Gulf of Mexico was down 61%, or 1.7 billion cubic feet per day (cfd), on Monday, BSEE said.

The amount of gas flowing to Cheniere Energy Inc’s Sabine Pass liquefied natural gas (LNG) export facility in Louisiana rose to a one-week high of 3.7 billion cfd.

Last week, the amount of gas flowing to Sabine fell to a 13-week low of 2.9 billion cfd on Thursday, according to Refinitiv.

Most refineries in southeastern Louisiana kept running through the storm except for Phillips 66’s 253,600-bpd Alliance, Louisiana, refinery, which the company began restarting on Monday.

The Alliance refinery was shut on Friday because of the threat of flooding and a mandatory evacuation order in Plaquemines Parish, where the refinery is located along the Mississippi River.