WASHINGTON — A month after Scott Pruitt began leading the U.S. Environmental Protection Agency, the former Oklahoma attorney general rejected an Obama-era recommendation from agency scientists to ban a widely used pesticide from use on food crops.

That means farmers can continue to spray chlorpyrifos on crops ranging from corn to cranberries. The change was welcomed by farm groups and the U.S. Department of Agriculture, which said farmers need access to the chemical to stop infestations.

But environmentalists, who had been working for years to get the Obama administration to crack down on the pesticide, were outraged. And officials in several states – all led by Democrats – now say that if the federal government won’t force the pesticide off their lands, they will. Seven states have sued the EPA over Pruitt’s decision. In at least four states, legislators have filed bills to ban the product.

“If it’s not going to be done federally, we should do it at the state level,” said Maryland Del. Dana Stein, a Democrat who introduced a chlorpyrifos ban. “This is the tactic. It’s the only available option.”

The chlorpyrifos quarrel is yet another skirmish in what is likely to be a yearslong battle between blue states and the Trump administration’s EPA. Already, Democratic-run states say they will sue over rollbacks of Obama-era regulations and crack down on fossil fuel polluters.

Caught in the middle of the chlorpyrifos debate are farmers such as Stephen V. Lee IV of New Jersey, a sixth-generation cranberry farmer who says the pesticide can save crops from serious infestations when no other chemical is working.

Lee testified against a chlorpyrifos ban bill in his state last year, telling legislators he had used the substance only three times in the past decade.

“It’s like the fire extinguisher or the red button,” Lee said in an interview.

He said he only uses chlorpyrifos when his existing pest management practices don’t stand up against a bug. The bill has been reintroduced this year.