A hearing officer reviewing the plans for a proposed cement factory in New Hanover County said the state and the company should do more work before permits are granted.

In a report issued Thursday, hearing officer Paul K. Muller said the state needs more information on how Titan America will control pollution from the plant it wants to build in Castle Hayne. The Division of Air Quality is considering a permit for the plant, which would produce 2 million tons of cement each year along with pounds of poisonous byproducts. Muller, the supervisor in the division’s Asheville office, reviewed the state’s draft air permit and public comments on it.

Among his recommendations are for the state to review impacts on soil and plants, and to ask Titan to determine how mercury from the plant would affect fish in the nearby river. The company should tell the state how it plans to keep mercury out of the Northeast Cape Fear River, which is under federal restrictions because of existing mercury pollution, Muller said.