BUTTE - Butte-Silver Bow County has agreed to test a new fuel additive in its fleet this winter, hoping the substance can increase fuel efficiency and reduce emissions as it's Bozeman inventor believes it will.

John VanDaveer, the county public works director, said the additive, called CA-40, will be used for about six months "in a limited scope," and officials will monitor its use to determine if it boosts gas mileage.

"From the development and testing, it looks like it's a real legitimate product," VanDaveer, said.

"If we see positive benefit," he added, "then we'll go full scale."

Commissioners last month approved the use of CA-40 in the county's fleet and agreed to provide its Bozeman-based investor with data.

CA-40, which is the color of molasses and the consistency of cough syrup, is the brainchild of Clyde Ritter, a retired pilot who has worked in the aviation engineering field. He said his product can reduce emissions while also enhancing lubrication and combustion.

He has been developing CA-40 for 11 years and approached Butte for a fleet test this fall. News of his product piqued widespread interest from individuals looking to improve fuel economy, he said.

"We got calls from as far away as Sweden, Colorado and back in Tennessee," Ritter said. "I had 300 phone calls the first week."

Ritter said he approached the county about testing his product because he likes the area and wants to promote economic development here.

To that end, he plans to move a small CA-40 manufacturing operation here in 2006. While it would initially employ only a couple of people, Ritter said he expects the business to grow.

"As time goes on, it could employ quite a few people," he said. "The people of Butte have really gotten behind this product. It is going to be a Butte product."

VanDaveer said the county expects to start using the product on a limited basis later this month. He believes it could offer benefits beyond fuel efficiency.

"It's a good conditioner for the internal working parts of an engine," he said. "Because of the chemical composition, emissions are reduced."