It is illegal to use or possess a tobacco product if you are a minor in Maryland and may be issued a criminal citation:
http://law.justia.com/codes/maryland/2005/gcr/10-108.html
This is not considered a tobacco product, so the only law on the books, in MD at least, seems to be a law prohibiting sale and subjecting retailer to $1000 fine per sale(and MD should start doing stings on that...)
Md. HEALTH-GENERAL Code Ann. § 24-305 (2014)
And prohibiting smoking - but smoking is generally defined as a burning tobacco product, which this is not.
There is no criminal law against possession.