The South Portland/Cape Elizabeth Chamber of Commerce issued a statement Wednesday opposing efforts to derail a controversial proposal to build a liquefied petroleum gas depot at Rigby Yard.

The City Council is considering a moratorium on development of propane storage and distribution facilities, as well as changes to the city’s fire protection and prevention ordinances that would require propane facilities to be developed a safe distance from anything considered “critical infrastructure,” including the Cash Corner Fire Station near Rigby Yard.

Both the moratorium and fire code changes are sought by opponents of a proposed $3 million propane depot at the rail yard between the Thornton Heights and Cash Corner neighborhoods. The project is proposed by NGL Terminal Supply Co., a subsidiary of NGL Energy Partners of Tulsa, Oklahoma, which includes Brunswick-based Downeast Energy.

“The Chamber of Commerce board voted to oppose any efforts to modify the city’s fire code or pursue a moratorium with the intended effect of prohibiting the proposed storage depot,” the chamber said in a written statement. “This project should be considered on its own merits, pursuant to existing laws, ordinances and municipal processes.”

The statement said further that the chamber’s board “encourages the city to permit this business proposal, as well as future proposals, to proceed as regulated by (existing) ordinances and planning processes.”

Such consistency “encourages business growth, economic development and continued prosperity in our region, while also ensuring an efficient process that nevertheless takes into account the health, safety and welfare of (South Portland’s) citizens,” the statement said.

NGL wants to build a propane depot at the rail yard off Route 1 because the company must leave its existing depot on Commercial Street on Portland’s waterfront by next spring, when the state plans to start expanding the International Marine Terminal. The company submitted an initial proposal in February, then a scaled-back proposal in September.

Consultants hired by the city determined in June that NGL’s initial proposal to install six 60,000-gallon storage tanks at Rigby Yard – 360,000 gallons of fixed storage – would violate a local ordinance that prohibits additional above-ground storage tanks that hold more than 25,000 gallons.

The scaled-back proposal calls for one 24,000-gallon fixed storage tank that would be fed by as many as 16 full and eight empty rail tank cars, each with a 30,000-gallon capacity. As pressurized tanks are emptied of liquid propane, the remaining space is filled with propane gas, according to the city’s consultants.

Opponents of the NGL proposal say that if more than two empty rail tank cars remained at the depot longer than 24 hours, they would violate the city’s prohibition against development of gas storage exceeding 10,000 cubic feet or 74,800 gallons.