Three vape shops sued the Baker administration Sunday over the state's emergency four-month ban on sales of e-cigarette products, a ban that their lawyer said amounts to a "death sentence."

Owners of Mass Dynamics in Weymouth, Boston Vapor in Salem, New Hampshire, and Vick's Vape Shop in Medford filed a complaint in federal court alleging that the ban is unconstitutional and will do irreparable harm to their businesses.

Craig O'Rourke, their attorney, told the News Service on Monday that he has heard from several other stores interested in joining the suit. People in the industry are worried they will not be able to cover rent, wages and other expenses, he said, since vape sales have been suspended until Jan. 25, 2020.

"It's going to put them out of business," O'Rourke said. "It's a death sentence. They're trying to figure out what to tell their families and their employees."

Massachusetts last Tuesday became the first state in the nation to halt sales of all e-cigarette products amid growing concerns over a mysterious lung illness associated with vaping.

Gov. Charlie Baker, who declared a public health emergency as he suggested the ban, said Monday that more than 70 cases have been identified in the Bay State and almost 900 nationwide, but that exact causes remain unclear.

Baker told reporters the administration is prepared for the lawsuit and stands by its actions, seeing a pause as necessary to get a clearer sense of the full risks associated with vaping products.

"People aren't really quite sure about why, and until we have a better answer on why, we felt the best thing to do is to put in a four-month ban," he said after attending a housing event in North Quincy. "Obviously people have the ability to go to court if they wish to, and we'll continue to make our case associated with the public health issue on this."

Both tobacco and marijuana products are affected by the widespread ban, which was approved by the state Public Health Council shortly after Baker announced it. Federal health officials are also closely examining the reports of respiratory problems, and Baker said he hopes to receive guidance from the Centers for Disease Control and implement a new regulatory framework "by the end of the ban."

The businesses in the lawsuit argue, though, that halting all sales for several months is a misuse of state authority. They claim in their complaint that, because they only sell products certified under Food and Drug Administration standards, the Baker administration is attempting to circumvent federal regulations in violation of the U.S. Constitution's supremacy clause.

Plaintiffs also allege the ban renders them incapable of fulfilling existing business contracts and disrupts the flow of vaping-product trade with states where no such pause is in effect.

"The declaration was arbitrary and capricious and enforcement of the ban denied my clients and other shop owners notice and opportunity," O'Rourke said. "Those are fundamental due process rights that are guaranteed to all Americans."

Following the outright ban in Massachusetts, the Public Health Committee advanced a bill banning the sale of all flavored tobacco one day after Baker's emergency declaration, and House Speaker Robert DeLeo said comprehensive legislation is in the works.

Michigan and New York had banned flavored e-cigarettes prior to the Massachusetts ban, and Rhode Island last week announced its own ban on flavored e-cigarettes.

Baker's announcement has been met with outcry from vape users, some of whom say the decision will push them back to cigarette use. The American Vaping Association is planning a Thursday rally at the State House to advocate for lifting the ban, promoting the event with the slogan, "Let Us Vape Not Smoke."