Retired federal employees in same-sex marriages who were unable to provide survivor benefits for their spouses because of the Defense of Marriage Act may now do so but that decision will come at a cost, the Office of Personnel Management has said.

The U.S. Supreme Court’s June decision striking down that law’s definition of marriage for federal benefits purposes as only between a man and a woman means that OPM “is now able to extend benefits to Federal employees and annuitants who are legally married to spouses of the same sex, regardless of the employees’ or annuitants’ states of residency,” the agency said in a Federal Register notice published Friday.

“Consistent with OPM’s long-standing policy of recognizing the legal foreign marriages of opposite-sex couples for purposes of the retirement benefit programs that OPM administers, OPM will also recognize legal same-sex marriages granted in countries that authorize such marriages, regardless of the employees’ or annuitants’ states of residency, for purposes of these programs,” it added.

OPM previously announced that in addition to providing survivor benefits, employees and retirees in same-sex marriages now may cover their spouses and children under federal employee insurance programs, including health insurance, under the standard eligibility policies.

While eligibility is automatic, employees and retirees are allowed through Aug. 26 to make certain enrollment changes, such as switching from self-only coverage to self-and-family coverage under the Federal Employees Health Benefits Program. Afterward, they will have to wait until the next regular benefits open season, which starts in November.

The survivor benefit option is one of the key features of the federal retirement package. In addition to a lifetime monthly benefit of up to about half of what the retiree earned through federal service, it conveys eligibility to continue FEHBP coverage for the life of the survivor, if the survivor is not otherwise eligible under that program.

The notice fleshed out OPM’s previous announcement that retirees who are in legal same-sex marriages will have two years from the date of the high court’s ruling, through June 26, 2015, to elect to provide survivor annuity benefits.

It warned that affected retirees “should be aware that electing a survivor annuity will require a reduction of his/her annuity to provide the survivor annuity” and that they “should consider their language carefully before sending OPM written requests regarding survivor benefits for their spouses.”

OPM said it will send an estimate and an election form to those who request information about the option. Those who send a signed statement or letter stating their desire to provide such a benefit also will receive an estimate but will be deemed to have made a final choice. The address is P.O. Box 45, Boyers, Pa., 16017-0045; all correspondence should include the person’s retirement claim number, while those electing to provide a benefit should include a copy of the marriage certificate.

Current employees in same-sex marriages similarly will be allowed to elect survivor benefits when they retire.

Separately, the Social Security Administration recently said it is working “to determine how the decision affects our programs, and to develop appropriate instructions for our personnel. We encourage individuals who believe they may be eligible for Social Security benefits to apply now, to protect against the loss of any potential benefits. We will process these claims as soon as we have finalized our instructions.”

Social Security is part of the retirement benefits package for most current federal employees and many recent retirees, although longer-term retirees typically worked under a different retirement system that does not include Social Security.

The 401(k)-style Thrift Savings Plan also is reviewing its spousal rights policies in light of the DOMA decision, although account holders already may designate anyone they choose as a beneficiary. Other spousal policies involve issues such as consent to certain withdrawal decisions and eligibility to keep an account in place after the participant’s death.