The Senate approved the legislation 48-0 on Wednesday and sent it to Gov. Mike Easley, whose office helped negotiate the final version.

"The governor believes it appears to be a good compromise and looks forward to reviewing the bill," said Seth Effron, a spokesman for Easley.

Any new farms would have to install waste disposal systems that substantially eliminate odors, airborne emissions of ammonia, discharge of animal waste into rivers and groundwater, and disease-carrying pathogens. The legislation directs environmental regulators to write those standards into law.

Still, the bill is a significant departure from the milestone that environmentalists envisioned would phase out all open-air hog lagoons. Originally, state leaders and hog producers agreed to explore such a phase-out when they signed a pact to research alternative waste disposal methods.

But under the bill that goes before Easley, farmers with existing waste lagoons could continue to use them indefinitely. In certain circumstances, they could replace failing lagoons that pose an imminent hazard with new ones.

Environmentalists said that this change weakened the bill. But hog industry officials contended that farmers could be put out of business otherwise. Although researchers identified environmentally superior methods of handling hog waste, none was deemed affordable.

"This moves us in the right direction," said Sen. Charlie Albertson, a Duplin County Democrat who introduced the original bill to try to make industrial hog farms better neighbors. "I don't think it's rational to set a date certain to phase out lagoons. We have to find a way to make some of the new systems more economically feasible."

North Carolina is the nation's second-largest hog producer, with an estimated 9.5 million swine on more than 2,300 farms, most of them in Eastern North Carolina.