Oil, chemical storage facilities vulnerable to monster storm.

Hurricane Harvey churned toward the Texas coast and its huge petrochemical complexes Friday, raising the specter of environmental devastation, economic damage and fuel-supply disruptions depending on where it makes landfall and how long it lingers.

Plans were in the works to possibly shut down the huge nuclear power plant on the coast — the South Texas Project about 10 miles inland from Matagorda Bay — as the stormed approached, although the plant’s two reactors were operating at full capacity as of late Friday afternoon. The plant, which is partly owned by Austin Energy, is designed to withstand sustained winds greater than 157 mph, officials said, and its reactors and equipment are encased in concrete and waterproof.

But Jim Blackburn, co-director of Rice University’s severe storm center, said the thousands of oil and chemical storage facilities along the Houston ship channel are vulnerable.

“If we had a 20- to 25-foot (storm) surge in the Houston ship channel, it would probably be the worst environmental disaster in United States history” because of the estimated 4,400 storage facilities along it, Blackburn said.

He noted that the forecast calls for a significantly lower storm surge in the channel. However, some models indicate Harvey could stall near Houston, dump heavy rain for several days, drift back to sea and then turn around to make landfall again.

“There are an awful lot of uncertainties,” Blackburn said. “I’m not as worried about the initial landfall. I’m more worried about five to six days of heavy rain, then coming back in” to make landfall a second time.

Meanwhile, a hit to the large number of oil refineries in the region could result in a significant impact to fuel supplies — if it resulted in lasting damage to them. Refineries near Corpus Christi account for 4.2 percent of U.S. refining capacity, according to AAA Texas, while Houston refineries account for about 14 percent.

But Tom Kloza, global head of energy analysis at Oil Price Information Service, said he’s optimistic damage to the region’s refineries won’t be significant, based on the storm tracking forecasts he has seen.

Hurricanes “rarely result in damage (to refineries) that lingers,” Kloza said.

Still, 1.25 million Texans or more could be left without electricity as high winds knock down power lines and toss trees and other debris into them, according to forecasting models by Texas A&M University researchers.

Blackburn also said there could be significant flooding of homes on the west side of Houston if rainfall forecasts prove accurate.

“You could have one of the most devastating floods Houston has ever seen, based on the projections that have been discussed,” he said.

At the South Texas Project, officials were in the planning stages for a possible shutdown of the nuclear facility and were coordinating with county, state and federal agencies.

Plant policy is to shut down the reactors when a storm’s sustained wind speeds exceed 74 mph, said Buddy Eller, spokesman for the plant. The current forecast is for winds to hit only 40 mph at the plant site, he said.

Still, he said a decision to shut it down could be made if the forecast changes and calls for higher winds. Alternatively, he said, Texas’s electrical grid operator, ERCOT, could ask the nuclear plant to remain online.