The Preservation Society of Charleston, the oldest such organization in America, deserves much credit for its recent work in establishing state historical markers devoted to major post-World War II civil rights sites. They cover a wide range.

One at the old Cigar Factory on East Bay commemorates a post-World War II strike by black female workers that provided the origins for the song “We Shall Overcome.” Another is a wonderful new marker now in front of the old Kress five and dime on King Street. It fully tells how a group of black students from Burke High School planned and carried out a sit-in against the whites-only policy at the lunch counter there. Their action provided a local breakthrough in challenging racial discrimination.

The most recent marker, on what is now the Medical University of South Carolina campus, unfortunately contains an inaccurate reference that during the 1969 Charleston hospital strike, “protests were marred by violence.” Striking black voters were protesting discrimination in pay and working conditions. They sought recognition as a union affiliated with a national group in New York.

The strike lasted 113 days. As Columbia Bureau Chief for the Charlotte Observer, I covered those events extensively. As South Carolina stringer, or non-staff correspondent, I wrote stories for The New York Times and also The New Republic. It became a national story. Mary Moultrie, a licensed nurse at what was then the Medical College Hospital, organized the strike to challenge widespread practices of racial discrimination that black workers faced at the College Hospital. Charleston County Hospital workers joined in.

The strike began in March. In May Ms. Moultrie strode with Coretta Scott King, a year after her husband Martin Luther King Jr. was murdered, at the front of a mass march in downtown Charleston. Andrew Young, Dr. King’s top aide, helped negotiate a final settlement. He later became a congressman, ambassador to the United Nations and mayor of Atlanta.

During the march through African-American neighborhoods, Young motioned to people on their porches, calling out, “Come join us.” They poured out onto the street, swelling the marchers to roughly 5,000 as it progressed, including national labor union leaders and six members of Congress. Walking in front was Charleston Police Chief John Conroy. Ms. Moultrie remembers Chief Conroy telling the police force he didn’t want anyone to fire a weapon. Despite many tense moments during almost months of protest, no violence came from strikers or their supporters.

Charleston city attorney Morris Rosen and banker Hugh Lane played quiet, but important roles in final negotiations with Young, hospital officials, and local strike leaders. Local civil rights activist Bill Saunders played a significant role in developing strategy throughout the strike. He also worked directly with white civic leaders and Gov. Robert McNair, who had imposed a curfew and activated a National Guard unit, in negotiating a settlement.

Behind the scenes, the Charleston Local of the International Longshoremen’s Association fully supported the hospital workers. Their threat to shut down the port of Charleston helped lead Gov. McNair to announce a settlement.

The final wording on the Hospital Strike marker came from the state Department of Archives and History, which had checked sources that turned out to be inadequate.

To correct the “violence” error will require a replacement marker at a cost of $1,900 to the Preservation Society.

Dr. Jack Bass is professor of humanities and social sciences emeritus at the College of Charleston and author or co-author of eight books.