Residents here rejoiced two years ago when gas companies poked into a mammoth natural gas deposit 2 miles under their homes, sparking a modern-day gold rush.

The companies offered residents tens of thousands of dollars an acre to drill on their land, enriching some folks overnight in this rural corner of northwestern Louisiana.

Then cows started to die. Methane seeped into the drinking water. Homes were evacuated when natural gas escaped uncontrollably from a wellhead.

Today, many residents and local officials still praise the bounty reaped from the Haynesville Shale, one of the world's largest natural gas deposits, spread under Louisiana, Arkansas and eastern Texas. An estimated 250 trillion cubic feet of natural gas is trapped there — enough to power the United States for more than a decade, says Kevin McCotter, a senior director with Oklahoma City-based Chesapeake Energy Corp., the largest gas producer in the area. The shale has delivered a clean energy source while enriching residents, he says.

"At a time when our nation needs jobs and domestic investment more than ever, the Haynesville Shale has been a flu shot for northern Louisiana and East Texas," he says.

Others question whether the money landowners get for leasing their property is worth the risk they say the drilling poses.

"There are a lot of concerns," says Kassi Ebarb, who organized neighbors in her Shreveport suburb to demand more environmental safeguards from gas companies. "We would walk away (from the money) rather than take anything that was insufficient to protect our neighborhood and our kids."

Shreveport and the surrounding area have entered a national debate on the safety standards of a specialized form of natural gas drilling that pumps chemicals and water into the ground to release natural gas trapped thousands of feet below.

The debate centers on the controversial technique known as "hydraulic fracturing," or "fracking," in which companies drill down, then horizontally to reach natural gas deposits trapped in a shale formation. A mixture of water, chemicals and sand then is pumped into the shale with great force, breaking up the rock and releasing the gas.

The technology allows drillers to extract previously inaccessible natural gas deposits and has opened huge swaths of the USA to drilling. Nearly 500,000 natural gas wells are producing in 32 states, up from 393,000 in 2003, according to the U.S. Energy Information Administration.

The percentage of natural gas drilled from shale formations using hydraulic fracturing is expected to climb from 14% last year to 23% in 2020, according to the Department of Energy.

Environmentalists warn that chemicals blasted into the ground during fracking could harm water supplies and release toxic air and water, threatening rivers, air quality and human health.

"We've gone from getting the easiest oil and gas to the hardest," says Gwen Lachelt, director of Earthworks Oil and Gas Accountability Project, a group advocating stricter drilling regulations. "It's getting dirtier and dirtier."

Gas companies and advocates of fracking say the technique is safe and poses little risk to drinking water or the environment. "We have a very good record when it comes to hydraulic fracturing, its regulations and the safety of the environment," says Jodee Bruyninckx of the Louisiana Oil and Gas Association.

Recent developments in fracking:

•The New York Assembly last week passed a temporary ban on hydraulic fracturing until next year, while regulators review permitting rules.

•The Environmental Protection Agency in March launched a two-year study of the effects of hydraulic fracturing.

•The Pittsburgh City Council last month unanimously approved a measure banning natural gas drilling from its city limits, citing health and environmental concerns.

•The EPA last year found high levels of benzene, hydrocarbons and other harmful chemicals in water wells near gas rigs in Pavillion, Wyo., after residents complained of a foul odor and taste in the water, the agency says.

•Pennsylvania environmental regulators recently blamed the methane contamination of an aquifer — a natural underground formation that stores water — near Dimock, Pa., on Houston-based Cabot Oil & Gas, which has been drilling into the region's Marcellus Shale. Cabot disputes the allegation.

A 'tough road' to regulation

Fracking is exempt from the federal Safe Drinking Water Act, an exemption passed under the 2005 Energy Policy Act, according to legislative records. Under the exemption, gas companies don't have to disclose the chemicals used in the process.

A bill known as the FRAC Act, introduced in Congress last year by Sen. Robert Casey, D-Pa., would compel gas companies to reveal those chemicals, which largely have been guarded as trade secrets, Casey says. The bill is not expected to make it to the Senate floor in the near future, given the current political climate in Washington, he says.

"There's a tough road ahead of us," Casey says.

Further testing and monitoring should be done on the technique, which also is exempt from sections of the Clean Water Act and other federal environmental laws, says Josh Fox, a filmmaker whose documentary film, Gasland, profiles families across the USA impacted by natural gas drilling.

The film, released this year, shows residents setting the water coming out of their faucets on fire because of flammable methane gas in the water.

"This process has never been investigated," Fox says. "We don't put out drugs in the market without testing them first."

Fears of faucets flaring because of fracking are overblown, says Gary Hanson, a hydrologist at Louisiana State University at Shreveport who has studied the technique. Hydraulic fracturing bores down more than 2 miles underground, well past aquifers that sit at less than 1,000 feet, making it difficult for the process to contaminate drinking water supplies, he says.

Even if it doesn't fall under federal safety rules, fracking is still monitored by state and local agencies, Hanson says.

"You're going to have some incidents. There are going to be some spills," Hanson says. "But I don't see major contamination occurring."

Some see drilling as a 'blessing'

The financial benefits have been undeniable. Last year, Haynesville Shale drilling brought $10.6 billion in new business sales to the state, $5.7 billion in household earnings and 57,000 new jobs across the state, according to a study commissioned by the Louisiana Oil And Gas Association.

"Not only is natural gas production — and Haynesville Shale in particular — boosting Louisiana's economy and creating jobs, this type of exploration is helping to fuel America and decrease our dependence on foreign sources of energy," Louisiana Gov. Bobby Jindal, a Republican, said in a statement.

Reegis Richard, pastor of the Temple of Knowledge Church International in nearby Mansfield, the heart of drilling activity, received $30,000 in gas money by leasing his church's 7 acres, and offerings from his enriched congregation have more than doubled, he says.

The influx of cash has allowed him to finish a new church building, open a private Christian school and travel twice to Israel with his wife and local ministers, he says.

"People's lives have been transformed," Richard says. "It's been a blessing."

The increased activity has also brought a greater strain on state regulators. In Louisiana, 38 oil and gas inspectors are responsible for monitoring the state's 19,000 producing natural gas wells, including 781 in the Haynesville Shale area, according to the state Department of Natural Resources.

State agencies "don't have the political will nor the budget or the staff to adequately address the level of drilling that's going on in this area," says Murray Lloyd, a local lawyer.

Last spring, the Caddo Parish Sheriff's Office received calls about cows in a pasture near a drilling rig that were foaming and bleeding at the mouth and keeling over, Sheriff Steve Prator says. Deputies found 17 dead cows there.

Necropsies later determined they had died from drinking fracking fluids that had leaked into the pasture, he says. Chesapeake and one of its subcontractors were later fined $22,000 each for the incident, according to the state Department of Environmental Quality.

Then in April, about 200 homes in rural Caddo Parish were evacuated when a gas well blew out, sending gas into the air and local water supply, Prator says. Regulators detected high levels of methane in water from residents' toilets and sinks, he says.

The incident prompted Prator to contact Jindal's Office of Homeland Security and create the Haynesville Shale Task Force to better plan for emergencies. Lack of coordination among state agencies and their overall handling of the events frustrated him, Prator says. Another worrying development: gas rigs creeping closer to schools and crowded neighborhoods, he says.

"It made me question, 'Are we doing the right thing?' " Prator says.

One of those evacuated during the blowout was Frances Contario, 50, who left her trailer near Wallace Lake and lived in a room at the Clarion Hotel in Shreveport with her 23-year-old son, Braden, for 17 days. EXCO Resources, the Dallas-based gas company responsible for the blowout, paid the residents' hotel tabs and expenses, Prator says.

Contario says she has been drinking only bottled water since returning and fears that the lake, streams and forests near her home will be fouled by under so much drilling.

"We didn't ask for this," says Contario, who grew up in the area. "Our biggest concern is that one day this will all be contaminated."