The World Without Us

The tankers, bearing flags of Middle Eastern nations, Mexico, and Venezuela, arrive at an appendage of the Ship Channel on Galveston Bay called Texas City, a town of about 50,000 that has as much acreage devoted to refining as to residences and business. Compared to their big neighbors—Sterling Chemical, Marathon, Valero, BP, ISP, Dow—the bungalows of Texas City’s residents, mostly black and Latino, are lost in a townscape ruled by the geometry of petrochemistry: circles, spheres, and cylinders—some tall and thin, some short and flat, some wide and round.

It is the tall ones that tend to blow up.

Not all of them, although they often look alike. Some are wet-gas scrubbers: towers that use Brazos River water to quench gas emissions and cool down hot solids, generating white steam clouds up their stacks. Others are fractionating towers, in which crude oil is heated from the bottom to distill it. The various hydrocarbons in crude, ranging from tar to gasoline to natural gas, have different boiling points; as they’re heated, they separate, arranging themselves in the column with the lightest ones on top. As long as expanding gases are drawn off to release pressure, or the heat is eventually reduced, it’s a fairly safe process.

Trickier are the ones that add other chemicals to convert petroleum into something new. In refineries, catalytic cracking towers heat the heavy hydrocarbons with a powdered aluminum silicate catalyst to about 1,200°F. This literally cracks their big polymer chains into smaller, lighter ones, such as propane or gasoline. Injecting hydrogen into the process can produce jet fuel and diesel. All these, especially at high temperatures, and especially with hydrogen involved, are highly explosive.

A related procedure, isomerization, uses a platinum catalyst and even more heat to rearrange atoms in hydrocarbon molecules for boosting fuel octane or making substances used in plastics. Isomerization can get extremely volatile. Connected to these cracking towers and isomerization plants are flares. If any process becomes imbalanced or if temperatures shoot too high, flares are there to bleed off pressure. A release valve sends whatever can’t be contained up the flare stack, signaling a pilot to ignite. Sometimes steam is injected so that whatever it is doesn’t smoke, but burns cleanly.

When something malfunctions, the results, unfortunately, can be spectacular. In 1998, Sterling Chemical expelled a cloud of various benzene isomers and hydrochloric acid that hospitalized hundreds. That followed a leak of 3,000 pounds of ammonia four years earlier that prompted 9,000 personal injury suits. In March 2005, a geyser of liquid hydrocarbons erupted from one of BP’s isomerization stacks. When it hit the air, it ignited and killed 15 people. That July, at the same plant, a hydrogen pipe exploded; in August, a gas leak reeking of rotten eggs, which signals toxic hydrogen sulfide, shut much of BP down for a while. Days later, at a BP plastics-manufacturing subsidiary 15 miles south at Chocolate Bayou, flames exploded 50 feet in the air. The blaze had to be left to burn itself out. It took three days.

The oldest refinery in Texas City, started in 1908 by a Virginia farmers’ cooperative to produce fuel for their tractors, is owned today by Valero Energy Corporation. In its modern incarnation, it has earned one of the highest safety designations among U.S. refineries, but it is still a place designed to draw energy from a crude natural resource by transmuting it into more explosive forms. That energy feels barely contained by Valero’s humming labyrinth of valves, gauges, heat exchangers, pumps, absorbers, separators, furnaces, incinerators, flanges, tanks girdled by spiral stairwells, and serpentine loops of red, yellow, green, and silvery pipes (the silver ones are insulation-wrapped, meaning that something inside is hot, and needs to stay that way). Looming overhead are 20 fractionation towers and 20 more exhaust stacks. A coker shovel, basically a crane with a bucket on it, shuttles back and forth, dumping loads of sludge redolent of asphalt—the heavy ends of the crude spectrum, left in the bottom of the fractionators—onto conveyors leading into a catalytic cracker, to squeeze another barrel of diesel from them.

Above all this are the flares, wedges of flame against a whitish sky, keeping all the organic chemistry in equilibrium by burning off pressures that build faster than all the monitoring gauges can regulate them. There are gauges that read the thickness of steel pipe at the right-angle bends where hot, corrosive fluids smash, to predict when they will fail. Anything that contains hot liquid traveling at high speeds can develop stress cracks, especially when the liquid is heavy crude, laden with metals and sulfur that can eat pipe walls.