Gov. Phil Murphy rolled out his long-awaited "comprehensive strategy" Thursday to dramatically reduce what he called the toxic "scourge" of lead in New Jersey's drinking water, homes and soil.

Murphy vowed his "multi-pronged" approach will serve as a "national model" for other states to follow. It includes $500 million in more borrowed money to subsidize the cost of replacing aging "lead service lines" that deliver water directly to homes and properties.

Yet, for all the fanfare — and the enthusiastic embrace of Murphy by his environmental and public health allies — there are reasons to doubt his ability to succeed or even to launch the campaign. Here are four of them.

The $500 million is far from a given

The proposed $500 million makes for a tidy sum and a sound bite, but it still needs voter approval, most likely on the 2020 ballot. But it may not be such an easy sell to voters in a state choking in debt. New Jersey, which once boasted a robust, triple-A bond rating, now has the second-worst in the nation, and its debt-to-asset ratio is the nation's highest.

Nobody is more aware of this than Murphy, who expressed worries about the state's fiscal picture when he cut a $1 billion bond referendum for school security. Lawmakers modified it to $500 million, which voters eventually approved.

Some critics argue that the $500 million Murphy asked for Thursday falls far short of what is needed to address the problem. Even Catherine McCabe, Murphy's environmental protection commissioner, estimated the tab at $3 billion at a press conference in Newark this summer.

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And here's another complication: The $500 million would be used to subsidize the cost of replacing the aging, underground lead service lines operated by municipal water utilities, like the embattled Newark and Trenton water systems. The average cost of replacing a line is $6,000, officials say.

But the money will not be available to customers who depend on privately operated water companies. Instead, these customers would be charged a modest rate increase to cover the cost, according to Murphy's proposal.

Stefanie Brand, director of the state's Division of Rate Counsel, warned that allowing utilities to charge ratepayers for work done on private property "is a slippery slope that could vastly increase rates and cause hardship for the very people we are trying to help."

A promised 10-year plan is pie in the sky

The governor called for replacing lead service lines within 10 years. But even if the Legislature quickly signs off on the ballot measure by next year and voters approve it, it could take several years before the proceeds will be available.

A 10-year goal also means the project will be at the whim of succeeding governors and legislatures, who are not obligated to carry out Murphy's promise. They will likely have other priorities.

Balking at declaring a 'public health' emergency

Jersey Water Works, the group of environmentalists and public health advocates that released its separate report Thursday, urged Murphy to issue an executive order declaring that lead poses an "immediate" threat to public health.

That step would have made the issue a top priority of his administration and infused it with a sense of urgency that, so far, has been lacking, especially in the Legislature, which has ignored more than 30 bills on the topic in recent years.

But an emergency order would also put more pressure on Murphy to deliver and would serve as a test of his ability to prod into action a Legislature where he has little clout, even though it is controlled by his own party.

A shortage of inspectors

In his remarks, Murphy acknowledged a looming shortage of professional water quality personnel to carry out his goals. As of August, there were only 60 certified lead evaluation contractors and 46 certified lead abatement contractors for the entire state. "We will need to greatly augment these ranks,'' he said.

The manpower problem echoes the difficulties that the state has faced in recruiting and training engineers to operate NJ Transit trains. It's a key reason for the cancellations this year and has bedeviled Murphy's promise to revitalize the crumbling transit system. The same issue now hovers over his call to action on lead.