E-cigarettes keep popping up for sale at county jails around the country even as some government officials, schools and health experts urge tighter control over the devices, especially in public buildings.

Electronic cigarettes, growing in popularity since their U.S. introduction about a decade ago, are showing up at jails in more than a dozen states, including Ohio, Illinois, South Carolina and Texas. The battery-powered, smokeless devices heat liquid nicotine solutions to produce inhalable vapor.

Many jail officials say the benefits of e-cigarettes outweigh any potential problems or health risks. They say e-cigarettes calm agitated inmates, decrease traditional cigarette contraband and bring in more revenue for the jails.

With most jails and prisons banning tobacco-burning cigarettes, inmates who smoke often suffer nicotine withdrawal and become agitated and short-tempered, said James Frye, chief deputy of the Shelby County Sheriff's Office in Sidney in eastern Ohio.

"We've seen a big improvement in behavior, with less arguments and fights," he said.

Thomas Borland, jailed in Shelby County since October on a driving infraction, said he is grateful he can buy e-cigarettes.

"They help calm me down," said the longtime smoker, who hopes the devices will help him quit tobacco cigarettes.

Other jails, including the Darlington County Detention Center in South Carolina, cite similar results with providing inmates e-cigarettes.

"Our main goal, though, was to cut down on people sneaking in cigarettes and loose tobacco, and we've seen a tremendous reduction there," said Maj. Mitch Stanley, the center director.

But the managing editor of Prison Legal News, which advocates for inmate rights, doesn't see any justification for e-cigarette sales in the prisons. He says the jails are just taking advantage of inmates addicted to tobacco.

"Jails that allow these devices don't do it for some altruistic reason but because they are making money off it," Alex Friedmann said.

Jails don't deny the sales bring in money but say they use the proceeds to buy uniforms, food and other inmate supplies at a savings to taxpayers. The Titus County jail in Texas has sold as many as 90 devices a week at $6 each, and Ohio's Shelby County collected over $17,000 in a year's time from the sale of $15 e-cigarettes.

In Tennessee, Davidson County Sheriff Daron Hall objects to the sale of the devices.

"We don't allow them and don't see any need for them," Hall said, adding that he's not seen any significant withdrawal problems with inmates coming off tobacco, especially compared to what those addicted to alcohol or drugs go through.

Hall said e-cigarettes would complicate things for his officers trying to enforce regulations in the county's smoke-free jail.

"Their jobs are hard enough, without having to sort out what kind of smoke or vapor they may see," Hall said.

Rock Island County Sheriff Gerry Bustos in Illinois doesn't want to sell e-cigarettes in his jail either but said he will review the issue at the local government's request. Among his concerns, Bustos said, is an apparent lack of knowledge about the effects on users and those around them.

Lawmakers in several states and cities have proposed adding e-cigarettes to existing bans on smoking in restaurants, hospitals, buses and other public places, and a growing number of schools are prohibiting them.

"Some people say they are safer than combustible cigarettes, but safer doesn't necessarily mean safe," said Dr. Otis Brawley, chief medical officer for the American Cancer Society.

He and other health experts worry about e-cigarettes and believe much more research is needed. A California Department of Public Health report last month said e-cigarettes emit cancer-causing chemicals and can hook users on nicotine.

Richard Lichten, a jail procedures consultant in Los Angeles, said "no good" can come from selling e-cigarettes to inmates.

"Why would you hand someone a tool that can be made into a weapon?" Lichten said.

Jail officials say the e-cigarettes they sell are made of soft plastic designed to prevent their use to hurt someone. They also don't expect to see the bartering once common with traditional cigarettes. Jails sell e-cigarettes one at a time and stamp them with the inmate's name or serial number to prevent trading. Inmates also must return their e-cigarette for a thorough check before buying another.

"Those abusing the privilege lose it," Frye said.