An Iowa man’s creation is helping fight illegal drugs and rural thefts. Makers of methamphetamine use anhydrous ammonia, a common farm fertilizer, and often steal it from storage tanks. Dave Christianson works for a major ag parts rebuilder in Humboldt, where he created the device brand-names “Tanks-a-Lok.”He he says he works all the time with all kinds of materials, explaining part of his job is to come up with ways to improve existing farm products. “This idea just popped into my head one evening, to build an ammonia lock.” He came up with a device to put on the large tanks of fertilizer kept at farm co-ops, dealerships and other storage facilities. He says as early as 1998 those owners knew there was a problem. That’s when they starting finding length of bicycle inner-tube attached to the tank valves, and figuring out what they were using the ammonia for. Thieves sometimes left the valves open, releasing clouds of the toxic ammonia and creating a safety hazard. Christianson says after he invented a lock for the valves, it caught on quickly. He’s sold more than 25-thousand of the tank locks, in various sizes and shaped to fit the valves on different tanks. They’re now in 25 states, he says, and Christianson’s in a project with the state of Iowa to lock up every tank in the state. The government’s helping pay to distribute the locks to fertilizer dealers. Funding comes from the federal government, and through the Iowa Office of Drug Control policy, it’s used to buy tank locks from Christianson’s company that go to local sheriffs. This month they’ve been distributed to anhydrous suppliers in Henry, Lee, Des Moines, and Louisa counties. “I’m on a mission,” Christianson says, “to give back to our community and society the gifts that we all should.” He says he believes in this project, and thinks it’s a serious attempt to help control drugs. County sheriff’s departments say they get frequent calls about leaking anhydrous tanks and blame it on thefts, or theft attempts, by drug makers.