Enterprising thieves have turned laundry detergent into “liquid gold.” They’ve stripped copper from churches and construction sites. And now the list includes an item that you never thought they would target: air bags.

Fairfax County police report that the safety devices have been stolen from more than 50 cars this year. And Arlington County police said a couple of weeks ago that air bags were stolen from multiple cars in the Fairlington area. Similar thefts were reported in Howard County in March and Montgomery County last year.

Police and experts say that there is an active black market for the items. Air bags retail for about $1,000, but stolen ones cost $50 to $200, according to the National Insurance Crime Bureau. The group reports that about 50,000 air bags are stolen across the country each year, totaling $50 million.

Crooked repair shops install stolen air bags and then pocket the difference between the lower black-market price and the market rate they charge the insurance companies.

“We’ve seen this before, but it’s become so brazen and bold they are selling these air bags on eBay and Craigslist,” AAA Mid-Atlantic spokesman John Townsend said. “When a shop is installing an air bag that’s stolen, it could be compromised. That’s a potential safety risk — they may not deploy as they are supposed to.”

If car owners are having an air bag installed, Townsend suggested that they ask to see the original packaging for the safety device or a receipt from the manufacturer for the purchase of the air bag.

The most recent air-bag thefts in Fairfax involved seven vehicles in the Fairfax City area during the overnight hours of April 4 and 5, police said. Nine vehicles parked in the Annandale area were hit overnight on April 9 and 10.

Some of the cars were unlocked, but in most cases the thieves broke the rear window of a locked vehicle, police said. The thieves open the hood, disconnect the battery and remove the air bag.

“They know what they are doing, and they are getting in and getting out,” said Shelley Broderick, a Fairfax police spokeswoman.

Roger Morris, chief communications officer for the crime bureau, said that a thief can snatch an air bag in less than a minute. The most popular cars to target are the ones that are most popular on the road, because it means a bigger resale market, he said.

“Stealing the vehicle is harder . . . than stealing an air bag,” Morris said. “Thefts have gone down for entire vehicles, but when it comes to rims, catalytic converters and air bags it’s a different story.”

Anyone with information about the air-bag thefts is asked to call Crime Solvers at 866-411-8477.