Objective To determine whether retail stores selling electronic smoking devices or liquid nicotine were compliant with North Dakota's smoke-free law.

Methods During June 2015, retail stores selling electronic smoking devices or liquid nicotine (n=16), but not legally required to be licensed to sell tobacco products, were assessed for compliance with North Dakota's smoke-free law by observing for smoking or e-smoking, or evidence of such, in prohibited areas and for the presence of required no-smoking signs.

Results Use of e-cigarettes, or evidence of use, was observed inside 8 (50%) stores required to be smoke-free. On the basis of all indicators of compliance assessed, compliance with the state's smoke-free law was low, with only 6% and 44% of stores compliant with all indoor and outdoor requirements, respectively.

Conclusions To the best of our knowledge, this is the first U.S. study assessing retail stores selling electronic smoking devices or liquid nicotine for compliance with the smoke-free law. The use of e-cigarettes, or evidence of use, occurred in the stores where it is prohibited by law. Overall compliance with the smoke-free law was low. These stores should be licensed by the state, as are other tobacco retailers, because this may assist in education, enforcement and compliance with the law and increase public health protection.