Sen. Maria Cantwell said Friday that a failure by Congress to pass a long-overdue farm bill would amount to a huge lost opportunity for Washington’s agricultural industry and Clark County’s exporters to tap Asia’s rising demand for Northwest food products.The Washington Democrat, speaking at the Vancouver office of the Western United States Agricultural Trade Association, said Congress has only until Sept. 30 to break a House-Senate impasse on a farm bill extension. Without an extension, she said, the nations would revert to farm policies set in 1949.Cantwell, accompanied by agricultural and local business representatives, focused on the bill’s funding for agricultural research and export market development. She sidestepped discussion about the political wrangling that has stalled the extending of farm policies that historically have won bipartisan support.“To me, the issue is the incredible economic opportunity at our doorstep,” said Cantwell, who stood beside a display of Washington agricultural products for a news conference. “Vancouver is the portal to that opportunity.”The agricultural sector remains Washington’s top employer, Cantwell said, with 160,000 jobs and $40 billion in revenue, representing 12 percent of the state’s economy. Some 70 percent of the Port of Vancouver’s exports are agricultural products, she said.