The New Jersey Legislature has never successfully overridden a veto by Gov. Chris Christie. The ban on accepting fracking waste, which the governor vetoed last year, would be a good place to start.

Few environmental issues are as contentious as hydraulic fracturing, the practice of accessing natural gas by injecting water, sand and chemicals into underground shale beds. Fracking technology has led to a natural-gas bonanza in places like neighboring Pennsylvania, where 9,000 fracking wells are in operation, and it has driven down energy costs. But environmentalists say the practice may cause long-term problems.

That hasn’t directly affected New Jersey, where the Department of Environmental Protection says there are no shale deposits where the practice would produce energy.

But what does affect our state is the disposal of fracking wastewater. Fracking generates millions of gallons of chemical-laced wastewater, so much that energy companies are looking for new ways to dispose of it. At least three New Jersey facilities, in Carteret, Elizabeth and South Kearny, have accepted fracking wastewater and sludge in the past, a practice the state Legislature voted to ban last year. Christie vetoed that legislation in September.

Environmental groups rallied in Trenton last week to encourage lawmakers to override that veto, and they say a vote to do so may be scheduled in the next few days. The 160 people at the rally — farmers, businessmen and environmentalists — cited DEP reports that showed high levels of radioactivity in one shipment of the waste, high enough to violate the treatment facility’s permits.

And radioactivity may not even be the most dangerous thing in fracking wastewater. Drilling fluids contain carcinogens and heavy metals, but no one knows the exact composition because fracking formulas are trade secrets. Energy companies do not even have to disclose to the federal government what is in the mixture they pump underground.

That mystery is exactly why New Jersey should not be accepting this waste. Our state is still struggling to overcome its past environmental sins. We don’t need to be adding to them, especially when we don’t know the exact composition of this material. Without that knowledge, it is impossible to know if the waste is being adequately treated before it is released into streams and rivers — and ultimately into our drinking-water supply.

Last year, the bill banning New Jersey treatment plants from accepting fracking waste easily passed in the Senate, but the Assembly vote was not as overwhelming. It may be difficult to find enough Republican votes for an override. So far, the Legislature has tried more than a dozen times to override a Christie veto, without success. But it’s time to try again.

Lawmakers should make a stand on this issue. Their votes could help protect the long-term health of millions of state residents.

Former Associate Editorial Page Editor and Graphics Editor at The Press. I’ve also worked as Managing Editor of Today’s Sunbeam in Salem and as a reporter at the Sentinel-Ledger in Ocean City. My comic strip, "Just Add Walter," was nationally syndicated.