Sept 30 (Reuters) - Several vape shop owners are suing the state of Massachusetts for implementing a four-month ban on sales of all vaping products and asked the court to deem it "unconstitutional."

Massachusetts imposed a ban on sales of all e-cigarettes and supplies, both those used for tobacco and marijuana, which is legal in the state, citing a national public health emergency.

U.S. health officials are investigating a mysterious vaping-related respiratory illness that has so far caused 12 deaths and sickened 805 people.

The ban will impact customers, wholesalers and corporations, the plaintiffs said in a lawsuit filed in the U.S. District Court of Massachusetts on Sunday.

The plaintiffs argue that the ban undermines the U.S. Food and Drug Administration's assessment that the Electronic Nicotine Delivery Systems (ENDS) products and e-liquids are safe to use and distribute.

The plaintiffs for the case are Mass Dynamics LLC, Boston Vapor LLC and Vick's Vape Shop.

The Centers for Disease Control and Prevention has urged people to not use e-cigarettes with marijuana ingredient tetrahydrocannabinol (THC) as latest data suggests that the high-inducing component may play a role in causing respiratory illness. (Reporting by Sathvik N in Bengaluru; Editing by Sandra Maler)