COLUMBIA — Thousands of people eligible to vote in South Carolina may not have the right identification they would need to cast ballots if an ID law goes into effect or even be able to get to an office that issues the cards, according to a study released Wednesday.

The research by the Brennan Center for Justice at New York University School of Law says more than 7,000 eligible South Carolina voters with no access to a car live at least 10 miles from an ID office that is open more than two days a week. Nearly 275,000 people — or 8 percent of South Carolina’s citizens of voting age — live at least 10 miles from such an office, according to the researchers.

Passed by a Republican-controlled Legislature and signed by GOP Gov. Nikki Haley, South Carolina’s law requires voters to present a driver’s license, DMV photo ID, passport, military ID or a new photo voter-registration card. It was blocked in December by the U.S. Justice Department, which said the requirement could keep tens of thousands of the state’s minorities from casting ballots and failed to meet requirements of the 1965 Voting Rights Act.

That law requires approval from the Justice Department for changes to South Carolina’s election laws because of the state’s past failure to protect blacks’ voting rights. It was the first such law to be refused by the federal agency in nearly 20 years.

The Brennan Center studied 10 states that have either enacted voter ID requirements or, like South Carolina, have laws that are on hold pending court cases. State Attorney General Alan Wilson has sued the federal government over its rejection of the law, and arguments are set for late September in U.S. District Court.

The Brennan Center also is playing a role in South Carolina’s lawsuit. Its attorneys represent the League of Women Voters, which is involved in the case as an interested party.

Nationwide, nearly half a million people who are eligible to vote don’t have access to a vehicle and also live more than 10 miles from the nearest office where they could get an ID needed to vote, according to the study.

“These laws undermine the principals of fairness and equality promised by our constitution,” Keesha Gaskins, a co-author of the study, said Wednesday on a conference call with reporters.

Many of those offices have limited hours or are hard to access, the study found. In Rock Hill, the only office that issues the IDs is miles outside the city center, where nearly 42,000 eligible black voters live, researchers found.

Because of the lawsuit, it’s questionable if South Carolina’s voter ID law, even if it receives federal approval, would be enacted before this year’s Nov. 6 general elections. State Election Commission executive director Marci Andino has said her agency was ready and willing to do what the law required to get both elections personnel and voters up to speed on the requirements, included holding seminars to educate voters and giving them information about how to get free ID cards.

But Andino also has said the commission would need at least four to six weeks to create a system to issue those IDs.

In September 2011, the state Election Commission said that nearly 217,000 registered voters in South Carolina lacked a driver’s license or DMV-issued photo ID.

Also that month, South Carolina’s Department of Motor Vehicles arranged to give 25 people a free ride to get a photo identification card to comply with the law.

Since that effort, there has been no open-ended campaign to get people to the DMV to obtain photo identification. But agency spokeswoman Beth Parks said Wednesday that DMV officials have actually gone to a handful of homes to take ID pictures for people who will need them under a new photo requirement for handicapped parking placards.

A spokesman for South Carolina’s chief prosecutor said Wednesday the argument that there are many people unsuccessfully trying to get the IDs falls flat. “Not a single person has been identified that can’t get a free photo ID from the county election commission,” Bryan Stirling said.