Topeka ? Shawnee County farmers are testing a new, advanced type of lock designed to protect a form of fertilizer that is a common target for people making methamphetamine.

County officials, Kansas State University extension agents and the Kansas Methamphetamine Prevention Project unveiled the new locks on Monday as part of pilot project designed to decrease the number of thefts of anhydrous ammonia from farms.

Anhydrous ammonia is considered one of the most economical nitrogen-based fertilizers for farmers. But it’s also popular with meth “cooks” who use the hazardous chemical to make their drugs.

Shawnee County extension agricultural agent Dean Davis said about 98 percent of meth labs seized in the county used anhydrous ammonia.

The hardened steel locks are permanently mounted to the withdrawal valve of the ammonia tank. A coded key tool is required to operate the value and take out ammonia.

The county has about 150 locks and plans to have them installed on farms across the county by this winter. Officials said they’ll study how useful the locks are and whether they help reduce the number of ammonia thefts.

“Over the next year, we will be evaluating them,” said Laurie Chandler, Kansas State Research and Extension director. “We also want to make sure we’re not adding a whole bunch of time to farmers’ workloads.”

The locks, which cost $100 each, are paid for with a grant from the Topeka Community Foundation, the Shawnee County Sheriff’s Office and the Edward Byrne Memorial State and Local Law Enforcement Assistance Program.

Ed Peck, who farms about 500 acres east of Tecumseh, was sold. He said someone this spring thwarted what he thought was a thief-proof lock and stole ammonia from his farm.

“This new type of lock looks like it may be the answer,” he said.

Extension officials said stealing ammonia isn’t just a hardship for the farmers but also can be dangerous. The chemical is highly flammable, burns skin on contact and can cause blindness, lung damage and death.

“It’s the danger of leaving the valve open,” Chandler said. “It destroys the hoses and can do a great deal of damage to property and people.”