A U.S. company that is seeking to drill for natural gas in New Brunswick is facing a class-action lawsuit in Arkansas over its use of the controversial hydro-fracking procedure.

Southwestern Energy has committed to invest $49 million into the province as a part of a three-year licence to search for oil and gas.

But in the United States it is already facing a claim for damages from about a dozen families in Pennsylvania. Now, another law firm has launched a class-action suit in Arkansas.

Tim Holton, the lead lawyer on the case, said hundreds of people could be included in the latest lawsuit.

Holton said the case started when one family's water well was turned into a gas well allegedly because of nearby fracking.

"The water well next door to their house began to spew methane. So much so that they ended up putting a flare in the person's backyard," Holton said.

Holton said other families have started coming forward with claims.

The lawyer said other people say their water wells have also been contaminated with chemicals, which they blame on the fracking procedure.

The debated hydro-fracking — also known as hydraulic fracturing — has caused many New Brunswick communities to discuss the strength of the province's mining rules.

Hydro-fracturing is a process where exploration companies inject a mixture of water, sand and chemicals into the ground, creating cracks in shale rock formations. That process allows companies to extract natural gas from areas that would otherwise go untapped.

The New Brunswick government has hosted a public meeting on the mining procedure.

As well, Southwestern Energy has hosted a series of open sessions to explain its plans.

N.B. urged to be careful

Holton said the New Brunswick government should be careful before allowing Southwestern Energy to use the contentious drilling technique in the province.

"There are rules, there are regulations. The question is: are they being enforced," Holton said.

"And I think to a large extent people wonder exactly how much do we know about what is being done to the earth when you hydraulically frack rock."

The lawsuit asks for millions of dollars in damages.

It also asks the court to order the drilling companies to pay for an independent monitoring of the water supply and health of the families.

The lawsuit was filed last week. The allegations have not been proven in court.

Southwestern Energy has not yet filed a statement of defence.