Mexico hit hard by quake, hurricane
More than two dozen storage tanks holding crude oil, gasoline and other contaminants ruptured or otherwise failed when Harvey slammed into the Texas coast, spilling at least 145,000 gallons (548,868 liters) of fuel and spewing toxic pollutants into the air, according to an Associated Press analysis of pollution reports submitted to state and federal regulators.
The tank failures follow years of warnings that the Houston area’s petrochemical industry was ill-prepared for a major storm, with about one-third of the 4,500 storage tanks along the Houston Ship Channel located in areas susceptible to flooding, according to researchers.
More of the massive storage tanks could be put to the test in coming days as Hurricane Irma bears down on Florida. The tanks are prone to float and break during floods, and Harvey’s unprecedented rainfalls revealed a new vulnerability when the roofs of some storage tanks sank under the weight of so much water.
Federal and state rules require companies to be prepared for spills, but mandate no specific measures to secure storage tanks at refineries, chemical plants and oil production sites.
Although Florida has no oil refineries, it has more than 20 petroleum product storage terminals in coastal communities and about 30 chemical companies with a presence in the state, including a significant number of facilities in the Tampa Bay area, according to the American Chemistry Council and U.S. Energy Information Administration.
“Tampa Bay is one of the most vulnerable cities in the country” to hurricanes, said John Pardue, a Louisiana State University professor who has researched problems with storage tanks during storms.
“But there’s no requirement that says when you’re in a hurricane zone you’ve got to do things differently,” Pardue added. “If we’re going to continue to put some of these facilities in harm’s way, it would be great to have some specific regulations” to safeguard storage tanks.
The storm surge from Harvey was small enough that the refineries in the Houston Ship Channel appear to have avoided the huge spills associated with past storms such as Hurricane Katrina, when ruptured storage tanks released several millions of gallons of oil including into residential areas, according to Jamie Padgett, an associate professor at Rice University who has inventoried the Houston Ship Channel’s storage tanks.
One difference during Harvey was that prior to the storm, some refineries apparently were able to fill up their storage tanks to make them less buoyant and therefore less prone to floating and being damaged, said Kyle Isakower, vice president of regulatory policy at the American Petroleum Institute.
That wasn’t the case with about a dozen smaller storage tanks that experienced spills in Fayette County west of Houston, said Ron Whitmire with EnerVest, the Houstonbased company that operated the tanks. The capacity of those tanks ranged from about 250 to 400 barrels, which he said was not large enough to resist the force of the floodwaters that swept them away.
“Do we plan for storms and hurricanes? Absolutely,” Whitmire said. “But nobody plans for 50-plus inches of rain.”
The record rainfall also exposed problems among almost 400 large storage tanks in the Houston area that have “floating roofs” that go up or down depending on how much fuel is inside the containers. The unprecedented rains that came with Harvey caused 14 of those roofs to sink, in some instances allowing the chemicals inside them to escape, according to company reports and Padgett of Rice.
There are no government rules dictating how tanks are designed. But the American Petroleum Institute has established industry standards for tank construction that call for tanks to be able to drain at a minimum 10 inches (25 centimeters) of rain over a 24hour period. Rain was falling at more than twice that rate during Harvey, Padgett said.
At least two of the floating roof failures occurred in gasoline storage tanks at Shell Oil’s Deer Park refinery and another occurred at Exxon Mobil’s Baytown refinery.
Pollution reports submitted by the companies to Texas regulators blamed the roof problems on Harvey’s excess rainfall. The reports said air pollutants including benzene, toluene and xylene were released into the atmosphere. Longterm exposure to such pollutants can cause cancer, although Texas officials said they never reached concentrations high enough in the storm’s wake to cause health concerns.