NEW YORK— Walmart Stores Inc. will extend its health care benefits to its US workers’ domestic partners, including those of the same sex, starting Jan. 1.
The nation’s largest private employer, which has been a target of attacks by labor groups for what they criticize as skimpy wages and benefits, said Tuesday that the changes were made so it could have one uniform policy for all 50 states at a time when some states have their own definitions of what constitutes domestic partnerships and civil unions.
Employees can enroll their domestic partners from Oct. 12 through Nov. 1.
Walmart defines domestic partners as spouses of the same-sex or opposite gender, and unmarried partners who are not legally separated who have lived together for at least 12 months, are not married to anyone else, are in an exclusive relationship, and plan to continue sharing a household indefinitely, says Randy Hargrove, a Walmart spokesman.
‘‘States have different definitions,’’ said Hargrove. ‘‘We are going to have our own definition that will apply to our associates.’’
The move, which was announced to Walmart workers in postcards sent to them Monday, follows the US Supreme Court decision in June to overturn a 1996 law that denied federal benefits to legally married same-sex couples. So the decision makes the federal government recognize same-sex marriages in states where they are legal.
Walmart also announced that it will be offering an eyewear care program, including eye exams, to its eligible associates, starting next year.
The Bentonville, Ark.-based chain has 1.3 million full-time and part-time US workers. More than half of the workers participate in health care plans, the company says. About 1.1 million Walmart workers and family members combined participate in Walmart’s health care plan.
Hargrove said that the company’s health care premiums are going up anywhere from 3 percent to 10 percent, a lower rate than in previous years.
‘‘We have been working to keep our costs down,’’ he added.