Companies are struggling with the question of whether to allow employees to use e-cigarettes in the workplace, according to The Wall Street Journal. Employers want to encourage workers to quit smoking regular cigarettes, but are unsure about the benefits of letting employees use e-cigarettes, or “vape,” in the office.

Major corporations are taking a variety of approaches to e-cigarettes. Exxon Mobil allows vaping in smoking areas. CVS Caremark does not allow employees to use regular or e-cigarettes at its corporate campuses. While Starbucks bans e-cigarettes for both employees and customers, McDonald’s allows them. UPS requires employees who use e-cigarettes or regular cigarettes to pay higher health insurance premiums.

While 24 states and the District of Columbia ban workplace smoking, only New Jersey, Utah and North Dakota have added e-cigarettes to the laws, the article notes. Most of the 100 cities that ban e-cigarettes where regular cigarettes are already banned have not addressed the issue of vaping in the workplace.

The issue is complicated by the debate over the safety of e-cigarettes. While scientists largely agree that e-cigarettes produce fewer toxins than regular cigarettes, many public health officials and advocacy groups say secondhand vapor from the devices is a pollutant, and its health effects are not known.

The Food and Drug Administration may release recommendations about possible restrictions on the sale and marketing of e-cigarettes in the next few weeks.