Telecommunications corporation AT&T may soon have to contend with a strike. Nearly 40,000 of its employees – more than 15 percent of the workforce – have authorized their union to call a strike, which could result in workers walking off the job by this coming Sunday. The union has been negotiating with the company over various issues, including cost of healthcare and job security.

The union, Communications Workers of America, has reported that the strike may be called if an agreement isn’t reached by midnight on Saturday, April 7th, when four labor contracts will expire. In addition to the topics of healthcare and job security, AT&T is discussing concerns such as benefits, guaranteed weekends off and employee work rules – technicians and call center employees who take care of customer inquiries – for each of the four union contracts. Each contract is dealing with different issues.

Libby Sayre, a union spokeswoman for the AT&T West region, said that workers in that specific region have numerous open proposals but have concentrated the majority of the talks on healthcare costs and costs being passed over to the employees.

AT&T refused to directly address the discussion for a public statement, but an AT&T spokesman said that the company is striving to work with the union in negotiating a fair contract. Over half of the employees at AT&T, around 55 percent, are represented by unions, including the Communications Workers of America, the International Brotherhood of Electrical Workers, and others.

Another spokesperson for the union expressed a similar sentiment as AT&T in a desire to complete negotiations and agree upon a contract that’s fair for both sides. The union has been putting together rallies and holding meetings in an effort to support the deal.

In March, AT&T and Communications Workers of America agreed on a temporary settlement with a contract that covered 9,000 employees in the company’s wireless business. For its businesses still utilizing those troublesome wires (whose employees are covered by the union in question), AT&T has six major contracts encompassing 70,000 employees that will expire in 2012. For the company overall, the soon-to-expire contracts will be affecting 120,000 workers.

AT&T spokesman Marty Richter told Bloomberg that the company is working to retain high quality jobs and protect its employees. “As one of the largest employers in America, we’re proud of the number of high-paying, middle-class careers we’ve produced,” he said. “Our goal is to do everything in our power to protect those careers.”

Last summer, Verizon Communications, an AT&T rival, faced a strike for two weeks after 45,000 of its employees had their contracts expire. That was almost eight months ago, and the company continues to negotiate with unions for a new contract.

An authorization of a strike is not a guarantee that the union will call a strike. Contracts may be extended while discussions are still being held.