As employers try to rid the workplace of tobacco products, many are including electronic cigarettes and other vapor-based nicotine delivery systems.

A 2014 survey of large employers by the National Business Group on Health showed that most employers do not allow employees to use e-cigarettes inside their facilities, while one-third restrict indoor use to designated areas.

“We only had one company in the survey tell us that they don't make employees use a dedicated area or go outside to use e-cigarettes,” said LuAnn Heinen, vice president of the Washington-based NBGH.

Considering the U.S. Food and Drug Administration's stance prohibiting manufacturers from marketing e-cigarettes as smoking-cessation aids, “and with the evidence still unclear as to whether they do help people quit smoking, it seems that our companies have taken the position that until we know more, they're not going to encourage employees to use them,” Ms. Heinen said.

Among the 89% of employers polled that have a formal policy governing tobacco use in or on company property, slightly less than half have updated those policies to specifically address e-cigarettes.

“It's a new enough issue that employers are still taking all sorts of action and inaction with respect to e-cigarettes,” said Brad Wolfsen, executive director at benefits administrator bSwift L.L.C. in San Francisco.

Despite the FDA's position that e-cigarettes do not qualify as nicotine-replacement therapies, a small percentage of employers said they do include the devices in their smoking-cessation programs, according to the NBGH survey.

“There's an absence of real data on how they fit into the whole smoking-cessation landscape,” said Jonathan Dugas, director of clinical development at wellness program provider Vitality Group in Chicago.

“Right now, we see them as a way to reduce the harm of regular tobacco use, but in the absence of real data on that, this is definitely an important and open issue in the workplace,” Mr. Dugas said.