Some 37,000 Verizon Communications workers in Massachusetts, Rhode Island, and seven other northeastern states are threatening to go on strike at any moment, after their contract expired at midnight Sunday.

The workers affected are all in Verizon’s legacy landline hard-wired phone business and its FiOS fiber-optic broadband/video service, which the company has all but stopped expanding in the Northeast. With the old-fashioned phone business in steady decline, the battle comes down to what that should mean for the pay and benefits of workers who serve the traditional landline operations.

“In all aspects of the contract, they're coming after us,’’ Ed Hastings, president of the International Brotherhood of Electrical Workers Local 2222 in Boston said in an interview Monday afternoon. In what have become bitter contract talks, Hasting said, Verizon's pushed to slash health and retirement benefits and layoff protections. “This is from a company that is making $1 billion a month,’’ Hastings said. “We're not talking about a company that's in trouble financially.’’

Thousands of “On Strike” placards have been printed up and readied for picket lines, which Verizon workers walked for two weeks four years ago before three more months of negotiations led to a new contract deal. Then, Verizon workers agreed to stick to the terms of their old contract, including non-wage and –benefit matters, while negotiating terms for a new one. This time, IBEW and Communications Workers of America are working “without a contract,” meaning under federal labor laws, they continue to get the pay and benefits they’ve been receiving, but how issues around workplace grievances and other non-compensation questions are handled are in something of a gray zone. Verizon unions say they remain poised to call a strike at any time.

Verizon Communications spokesman Philip G. Santoro agreed that health and pension benefits and layoff protections are key issues in the talks. “We’re asking them to consider a small increase in their health care coverage costs, and they’ve actually asked that we go back to a time when they didn’t have to pay for their health care,’’ Santoro said.

“Our union-represented employees have always had terrific jobs with terrific benefits,’’ Santoro said. “If and when we reach agreement on a new contract, we're absolutely sure that that will continue, that our employees will continue to enjoy terrific benefits and terrific wages.’’ Santoro said that “in Massachusetts, the average technician earns $130,000 in wages and benefits’’ and the company is now only trying to rationalize benefit levels for an era in which landline phones and digital subscriber line Internet are competing with a half-dozen wireless carriers, Comcast and other cable companies, and instant messaging and chat services.

“The world has dramatically changed for them and us,’’ Santoro said. “The contracts they’ve created over the past were done at a time when our company was a monopoly. That is no longer the case … They’re asking for a guarantee that they'll never be laid off, and in this environment, in this world, that just can't happen.’’

The labor strife does not involve Verizon Wireless, which is non-union, and since the spinoff of Verizon Communications landlines to FairPoint in northern New England, involves only Rhode Island and Massachusetts landline operations.

Were Verizon workers to strike, it’s unlikely landline phone, DSL, and FiOS customers would see any immediate service impacts. Rather, the question would be how quickly non-union employees – managers and supervisors filling in as line crews, and replacement workers – could repair service failures and handle requests for new lines and moving service from one location to another.

Where a strike might have the most pronounced impact in Massachusetts are the 43 of the state’s 351 cities and towns that, according to the state Office of Consumer Affairs and Business Regulation, have only phone service and no cable. Mostly, they are small towns between Pittsfield and the Pioneer Valley in Western Massachusetts, and rural communities such as Petersham, Princeton, Royalston, and Franklin in Worcester County.

Hastings and other union leaders contend Verizon seemed to all but dare them to strike, hoping to draw workers into a costly, protracted walkout that could crush the union and force workers to agree to deep pay and benefit cutbacks. Now, they say, they are avoiding that trap and deciding if, and when, they go on strike, while rank-and-file workers continue to get paychecks and health coverage and the company runs up millions of dollars in expenses having replacement workers on standby.

“They came in with a ridiculous proposal on June 22nd, and basically waltzed us through the process for six weeks with no serious negotiations,’’ Hastings said. Santoro and Verizon officials say, however, many of the union’s demands have been unclear and moving targets during negotiations.