A separate damaged oil tank near Seadrift. Photo: Reuters

Two ExxonMobile refineries have been damaged by Hurricane Harvey, causing hazardous pollutants to leak and an “unbearable” chemical smell over parts of Houston.


ExxonMobil acknowledged in filings on Tuesday that a floating roof covering a tank at the oil company’s Baytown oil refinery sank, causing abnormally high emissions, especially of unstable organic compounds, which are regulated chemicals.


The Baytown refinery is the second-largest in the country. ExxonMobile said it would need to empty the tank in order to make repairs, but that isn't immediately possible with Harvey threatening to make landfall a second time.


An ExxonMobil spokeswoman said the company would “conduct an assessment to determine the impact of the storm once it is safe to do so,” The Washington Post reported.


The company did not say what was in the tank.


At least 3.6 million barrels per day of refining capacity are offline in Texas and Louisiana, or nearly 20 percent of total U.S. capacity, based on company reports and Reuters estimates. Restarting plants even under the best conditions can take a week or more.

As a result of the outages, major pipelines carrying gasoline, diesel and jet fuel started to adjust deliveries or close lines outright because of a lack of supply. U.S. gasoline futures <RBc1> surged 4 percent to settle at their highest in more than two years.

The U.S. Gulf Coast is home to nearly half of domestic refining capacity, with some 5.6 million bpd of capacity in Texas and 3.3 million bpd in Louisiana.

More refinery closures were expected, as parts of Texas have received more than 4 feet (1.2 meters) of rain. Fuel prices were expected to keep rising as refining capacity remains down and pipelines run short. Explorer Pipeline, which runs from Texas to Chicago, will shut two lines early on Wednesday.

"These closures are already impacting markets, with crude prices lower on a perceived drop in demand and gasoline prices spiking in response to lower supply," said Sandy Fielden, director of oil and products research at Morningstar.

Reuters contributed to this report.