Mobile anhydrous ammonia tanks at R&W Fertilizer in Ray were locked up weeks before state rules requiring the extra security went into effect.

Manager Doug Perdue said news about the proposal and frequent visits from thieves were enough to prompt early action.

"You could tell it was going to be done," he said. "And we were having enough trouble that I was going to do it anyway."

Thursday was the first day farmers and chemical dealers in two northwestern counties were required to lock mobile tanks of anhydrous left unattended overnight.

The program aims to cut thefts of the popular farm fertilizer by those who use it to make methamphetamine. If successful, it could be expanded beyond McKenzie and Williams counties.

The counties were chosen for the experiment because of the prevalence of meth in the area. Authorities say a quarter of the 295 meth lab busts recorded last year were in Williams County.

Perdue said that after about five weeks, locks already have stopped thieves from tapping into his mobile "nurse" tanks.

"They've been back. But they just can't get into 'em," he said with a laugh.

Some producers and chemical merchants have criticized the experiment as saddling them with too much responsibility for curbing meth-related crimes.

Others have complained about the cost, but the state will offer rebates through the Williams County auditor, said Jeff Bitz, who handles the program for the state Insurance Department.

"This way, we're not driving the market. We're not going to be the ones purchasing the locks, they are," Bitz said.

A typical lock would cost about $85, and some tanks with multiple valves could need up to $500 in locks. There are about 200 nurse tanks in the two counties, Bitz said.

Bulk dealers in the two counties should soon receive information on companies that sell approved locks, he said. Refunds likely will be issued within a few weeks of submitting the required paperwork.

Violating the rules can cost $100 for a first offense, $500 for a second offense and $5,000 for three or more offenses. However, officials say fines likely will be levied only if a farmer or dealer repeatedly refuses to follow the rules.

At Herman Oil in Williston, Bob Herman had just returned from vacation on Thursday and did not have locks on his nurse tanks, but said he would comply.

"I'd like to figure out ways of stopping these drugs. I'll do what the law is," he said.

But Herman also wonders how effective the program will be, and says it adds one more task to the farmer's long workday.

"As far as being a hassle, its going to be a problem even after we get the locks," he said. "We all work from daylight to dark."