TRENTON — For the second time in two years, Gov. Chris Christie has vetoed a bill that would have banned the dumping of fracking waste in New Jersey.

Environmentalists and lawmakers from both parties had championed the measure, which would have prohibited companies from treating, discharging, disposing, and storing waste from hydraulic fracturing — the controversial practice of pumping water, sand, and chemicals deep underground to harvest natural gas.

Though an increase in fracking has caused U.S. energy production to spike in recent years, critics worry that the practice could pollute drinking water supplies. And while fracking doesn't happen in New Jersey, environmentalists say it does take place in neighboring Pennsylvania and that companies have transported waste to at least three sites here — in Carteret, Elizabeth, and Kearny.

This bill (S1041/A2108) — sponsored by four dozen lawmakers — would have outlawed that. Supporters said it also would have put safeguards in place should companies begin fracking gas deposits in western New Jersey.

But as he did in 2012, when he rejected an earlier version of the bill, Christie argued that the measure would have violated the constitutional commerce law that says states shouldn't pass laws that discriminate against one another.

"At that time, I explained the lack of frackable shale in New Jersey meant that the bill's ban on fracking waste 'from any state' necessarily meant that the bill intended to embargo out-of-state waste," the Republican governor said in his veto message today. "This, I explained would have created an unconstitutional restraint on interstate commerce."

Christie added that the law hasn't changed since his last veto "in a way that would cause me to sign a bill that I previously rejected on constitutional grounds."

This is the third time Christie rejected legislation aiming to crack down on fracking. In 2011, he conditionally vetoed a bill that would have banned the practice outright in the state.

Critics have accused Christie, a potential 2016 presidential candidate, of vetoing such measures to curry favor with Republican voters and protect his chances at the White House.

"Instead of protecting from New Jersey from being dumped on, he sided with his national political ambitions," Jeff Tittel, president of the New Jersey chapter of environmental group the Sierra Club, said today. "He basically said to New Jersey, 'Get fracked.'

State Sen. Bob Gordon (D-Bergen), one of the measure's main sponsors, also slammed the decision.

"The liquids used in fracking are toxic substances that are known to be hazardous to humans, and this legislation would have protected New Jersey residents from that danger," Gordon said in a statement. "One of the main responsibilities of government is to protect its residents from harm, and today Gov. Chris Christie failed that test."

Assemblyman Reed Gusciora (D-Mercer), another sponsor, said the veto "puts New Jersey in the Twilight Zone of 'Junk Science' states."

Doug O'Malley, director of Environment New Jersey, said Christie's move "doubles down on his same mistake from two years ago" and called for members of the Democratic-controlled state Legislature to override the veto.

Lawmakers have never mustered enough votes to overturn one of Christie's vetoes.

EDITOR'S NOTE: This story originally said environmentalists claim that fracking waste has also been transported to a site in Pennsville. The mayor's office disputes that claim. The facility has not yet returned a message seeking comment.

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