Associated Press

TULSA, Okla. (AP) Oklahoma officials said Friday they are discouraging swimming in Grand Lake because of potentially dangerous blue-green algae a statement that drew a quick response from the governor, who was concerned about the effect on tourism over the holiday weekend.

Gov. Mary Fallin said she was extremely concerned about the economic damage that could result if people canceled trips to the northeastern Oklahoma lake at the last minute.

"There are still a lot of great things to do at the lake, even though there are concerns about the quality of the water," Fallin told The Associated Press.

Public pools are available for swimming, and there's golf courses, fireworks, an air show, free concerts, a carnival and numerous tourist attractions in the towns near the lake, including Grove, Pryor, Salina, Langley and Miami.

"I've had calls from businesses at the lake expressing concern about the effect on business and revenue," Fallin said. "Grand Lake is a wonderful tourism spot for Oklahoma. There's a lot of economic activity at the lake. We need to do all we can to support the lake."

Fallin's family had already planned a trip to Grand Lake over the Independence Day weekend and "we're still going," she said.

The GRDA is "strongly discouraging" swimming or other activities that would bring people into contact with the water, agency spokesman Justin Alberty said. The agency issued the advisory because of rapidly changing levels of blue-green algae in the lake, he said.

The agency's board of directors scheduled an emergency meeting in Tulsa on Friday afternoon to discuss the situation.

Blue-green algae are microscopic organisms that are naturally present in lakes and streams, usually in low numbers. However, the algae can become abundant in shallow, warm water that receives heavy sunlight. Most blue-green algae aren't toxic, but toxins harmful to humans and animals can be produced in some algae blooms, which is the case at Grand Lake.

Grand Lake was created in 1940 after the completion of the Pensacola Dam on the Grand River. It covers parts of four counties and holds about 59,200 surface acres of water, according to the lake's website. The shoreline is more than 1,300 miles long.

Copyright 2011 The Associated Press.