Premier Christy Clark set off Thursday on her fourth trade mission to Asia, after sidestepping questions about the environmental impact of liquefied natural gas export plants on the Kitimat-area environment.

A new report from environment group Skeena Wild concludes that if three LNG processing plants are built to burn natural gas for compression and cooling – what the industry calls direct drive – they would use two and a half times more gas than Metro Vancouver. The report calls for modern gas-fired power plants to be built outside the narrow Kitimat Valley to reduce the impact of sulphur dioxide and other pollutants that affect air and water quality.

Speaking to reporters at Vancouver airport, Clark rejected the report’s claim that the government has “tacitly endorsed” the use of direct-drive production of LNG.

“The study can’t have final answers on any of that, because they don’t know yet how liquefied natural gas plants will be powered,” Clark said. “We don’t know how many there will be. We’re still in negotiations with the companies about how all that’s going to unfold.”

Environment Minister Mary Polak said in an interview that one LNG proposal has applied for an environmental assessment, and two others are in discussions on B.C.’s technical requirements for a permit and how the plants would be powered.

“Nothing like that has been finalized yet, and of course we are concerned about what that means for a constrained airshed like Kitimat, because we know that there are a number of facilities proposed for Kitimat,” Polak said.

Polak announced in October that $650,000 has been spent on a study of LNG impact in northwestern B.C. Results are expected by the end of March. U.S. Chinese, Japanese, Korean and Malaysian LNG investors expected to make final investment decisions on B.C. proposals later in 2014.

The expansion of Rio Tinto-Alcan’s aluminum smelter has already required a 50 per cent increase in the plant’s allowable sulphur dioxide emissions, from 27 to 42 tonnes a day. New technology is expected to reduce the smelter’s output of fine particulates, polycyclic aromatic hydrocarbons, fluoride and other pollutants when the upgrade is in operation in 2014.