While a state-released report by BNSF Railway about the number of large Bakken crude oil trains passing through Central Oregon shows a potential notable increase, a company spokesman said Monday the actual number of trains is less than detailed in the report.

Following relatively new federal rules about reporting oil trains, BNSF Railway Co . sent a Sept. 30 report to the Oregon Office of the State Fire Marshal showing that an estimated zero to three oil trains carrying more than 1 million gallons of crude oil each pass through Deschutes and Jefferson counties per week.

A report earlier this year showed one such train passed through Central Oregon weekly.

“The real number is one every 12 days,” said Gus Melonas, spokesman for BNSF. That works out to three or four of the trains per month going through Redmond, Bend and beyond. He said the trains are carrying the oil to refineries in California.

The trains going through Central Oregon and the Columbia River carry crude oil from the Bakken region of North Dakota, oil that has proved to be more volatile than other crude oil. Bakken oil train derailments have led to dramatic explosions in Canada and North Dakota. Last May, the U.S. Department of Transportation issued an emergency order requiring railroads to provide information to state emergency responders about large train shipments of Bakken oil.

The BNSF rail route through the Gorge, bringing crude oil to refineries near Portland and in Washington, sees two to three oil trains per day, Melonas said. He said the route through Bend is “not a high volume line.”

The reporting rules pertain to trains carrying 1 million or more gallons of crude oil, the equivalent of about a 35-car train.

“If they have a train carrying less than a million crude, they don’t have to report it at all,” Rich Hoover, community liaison for the Office of State Fire Marshal, said Monday.

Melonas declined to give details on whether there are trains carrying less than a million gallons of crude oil rolling through Central Oregon, citing security and customer information concerns. If there were, he said, the oil cars would be hauled with cars carrying other commodities.

“We don’t put out specifics,” he said.

Each time a railroad company has an increase or decrease of 25 percent or more in the number of trains passing through an area, the rules require it to send a report to the state. Since May, BNSF has sent three reports to Oregon.

The company’s most recent report shows a change in data format. In the first two reports, BNSF reported the actual number of trains passing through Central Oregon during a specific week. While the new report still focuses on a specific week, the company is now giving a estimated number of oil trains.

Hoover said the state goes by what the company states in its reports , which the Office of State Fire Marshal posts to its website.

“What you see and read is exactly how much we know,” he said.

Melonas described the trains traveling through the region as “unit trains,” meaning they haul one commodity, and each train has about 100 tanker cars. The trains hold 70,000 to 80,000 barrels of crude oil each, or about 2.94 million to 3.36 million gallons of crude oil.

Concerned about the possible catastrophic results of an oil train derailment, Sally Russell, Bend city councilor, said it is a good thing the railroad is having to supply information to the state.

“Knowledge and the ability to response and react are critical,” she said.

If the number of large oil trains passing through Central Oregon is going up, it means the potential for a situation necessitating an emergency response is increasing, Bill Boos, deputy chief of fire operations for the Bend Fire Department, said Monday.

He said he’d like to have information on oil trains, large and small, rolling through Bend.

“It would be nice to know if there were smaller quantities coming through and if that was increasing,” he said.

While concerned about the dangers of train derailment and fire in towns, Michael Lang, conservation director for Portland-based Friends of the Columbia Gorge, also worries about the risks of an oil spill into the Deschutes River. The rail line through Central Oregon follows the river north of Bend. Along with towns, the large oil trains pass through a section of designated Wild and Scenic River.

“It’s not safe,” Lang said. “It endangers our communities, it endangers our environment. … And we are really concerned about it.”