HOBSON — At the back of a South Texas uranium processing facility, a few dozen black container drums stood outside, waiting to be shipped. Each was filled with about $50,000 worth of yellowcake, a powdery substance created from raw uranium.

“That’s pretty close to a Lexus in every drum,” said Gregory Kroll, the superintendent of the site, which is run by Corpus Christi-based Uranium Energy Corporation. The company mines the uranium in Duval County and brings it here for processing, before sending it on to a plant in Illinois, where it is further refined.

Company officials hope that the Hobson plant will increase its yellowcake production, now at 200,000 to 250,000 pounds per year, far below the plant's capacity. Uranium has been mined in Texas for decades, but companies see a potential hike in demand for their product. They are ramping up for a new push, despite concerns from environmental groups that past operations have not been sufficiently cleaned up and pose a threat to aquifers that people drink from.

Last year, the Texas Railroad Commission granted five new permits for uranium exploration in Texas, more than in any year since 2007. Two more exploration permits are being processed, one in Bee County and the other in Goliad County and both sought by Uranium Energy.

Uranium companies’ enthusiasm might seem surprising, given the shockwaves caused by last year’s nuclear disaster in Japan. Even Texas’ two nuclear plants felt the jolt: Both had been planning expansions, but that talk has subsided.

But companies like Uranium Energy are anticipating increased long-term demand for nuclear power from places like China and Saudi Arabia. Also, a big source of supply for American power plants is set to end next year, with the expiration of a program in which uranium from old Russian warheads gets diluted and sent to power plants in the United States.

Dale Klein, the associate director of the Energy Institute at the University of Texas at Austin and former chairman of the Nuclear Regulatory Commission, said the Russian warhead program could be renewed. Nonetheless, he said, “I think the demand for uranium will continue to increase.”

Texas, Klein added, is a “key player, but they’re not a big player” in global uranium production, which is led by Kazakhstan, Canada and Australia.

Only eight uranium mines were operating in the United States as of 2010, according to the Energy Information Administration. These include two in Texas — one in Duval and one in Brooks Counties. Six uranium production facilities operate around the country, including two in Texas, two in Wyoming and one each in Nebraska and Utah. Texas has less than one-tenth of the reserves of Wyoming, the leading state, according to the latest EIA data, from 2008.

South Texas has long been a hub for uranium mining. The metal, derived from ancient volcanoes, is found in a soluble form in aquifers. Often it lies near oil and gas deposits, a result of the way both substances have traveled through fissures in the ground. (Indeed, some of the mining and processing facilities lie in the booming Eagle Ford Shale.)

Today, all mining in Texas is done through a process called “in-situ leaching,” in which oxygenated water is sent into the aquifers to dissolve the uranium. The fluid that comes back up runs through resin pellets that clamp onto the uranium. The resin, which is reusable, gets transported to facilities like Hobson, which remove the uranium and turn it into yellowcake.

In past decades, “open pit” mining was the norm, but that stopped in Texas in 1992, according to Kevin Raabe, an official with Rio Grande Resources. The old open-pit mines are supposed to be “reclaimed,” or filled with materials like clean soil that cover the uranium. Raabe’s company manages an old open-pit site in Hobson where Chevron began mining uranium in the 1970s. Cows graze over where the pit used to be.

Some residents seem unperturbed by the old mine sites around South Texas.

“We have a reclaimed uranium pit on our property,” said Jane Mutz, a Falls City resident with land near Fashing. “We eat the fish out of the tank,” she added, referring to a large watering hole.

But Richard Lowerre, an Austin lawyer with Lowerre, Frederick, Perales, Allmon and Rockwell, has been fighting uranium companies for decades and said that many former open-pit mining areas remain unsafe for human habitation.

As for the modern in-situ mines, the companies are supposed to restore the quality of the aquifer to its condition before the mining began, according to the Texas Commission on Environmental Quality, which issues mining licenses and regulates the operations, by designation of the Nuclear Regulatory Commission. (The Railroad Commission’s permits cover exploratory wells only.)

Lowerre and other critics say that companies never do a full cleanup of aquifers.

A 2009 report by the U.S. Geological Survey found that most Texas uranium well fields contained a higher concentration of uranium after mining was completed than before.

Raabe acknowledged challenges, but he said that the water was nonpotable in any case. “Does it really matter if there’s 0.3 parts per million uranium in the water before you started mining and when you ended, it ends up at 0.8?” he said. Both numbers, he said, are “orders of magnitude above the drinking water standards.”

The industry also says that the uranium is essentially immobile — a point contested by environmentalists, who say it can migrate very slowly.

“In the 40 years this industry has been active, there’s never been a well, private or public, that’s been harmed by this process,” said Harry Anthony, chief operating officer for Uranium Energy.

George Rice, a San Antonio-based hydrologist who has testified for opponents of a uranium operation in Kleberg County, said this may be the case, but that the issue is inadequate monitoring. “If contamination has occurred, they haven’t looked for it,” he said of mining companies.

In Kleberg County, the legal wrangling centers on restoration of a site called the Kingsville Dome, which has been mined periodically over the years but is currently not operating. The county, represented by Lowerre’s law firm, and the mining company, Uranium Resources Inc., are disputing issues related to the standards the company must meet for cleanup. A trial resumes in early May.

Mark Pelizza, a senior vice president of URI, said the company, which could resume mining on the site, would “certainly like to see the issue revolved.”

Another fight is in Goliad County, where Anthony’s company wants to begin mining uranium in the Evangeline Aquifer but has run into opposition. The aquifer is the county’s sole water source and “could be significantly harmed” by uranium mining, according to a letter last month to the Environmental Protection Agency from a group that includes the Goliad County Groundwater Conservation District and Blackburn and Carter, a Houston law firm. Anthony said that is the “same old stories we’ve heard for 40 years, and none of it is ever true.”

The EPA is considering an “aquifer exemption” permit for the Goliad County operation — something all in-situ uranium mines need before proceeding. Anthony complained that the requirements from the EPA, which has been studying the permit since Texas officials approved it last year, are unprecedented.

A regional EPA spokeswoman, Jennah Durant, the agency is taking "appropriate caution" because of the presence of drinking wells and did not know when the Goliad review would be complete.

The EPA is also considering new national standards for monitoring of in-situ sites.

Editor's note: An earlier version of this article incorrectly stated the number and location of uranium mining facilities in the U.S.. There are six uranium production facilities, not uranium mines, in the country. (A production facility manufactures concentrated uranium.) Two of the production facilities are located in Texas, two in Wyoming, and one each in Utah and Nebraska. There were eight operational uranium mines around the country, including two in Texas, according to the latest EIA data, which is from 2010.