SÃO PAULO, Brazil — Black Brazilians have reappropriated an insulting quip by a prominent television anchorman, using his words — “It’s a black thing” — to draw attention to contributions of Brazilians of African ancestry and to the lingering impact of racial subjugation in Brazil.

The quip was made in a video that was recorded last year but that only surfaced this week in Brazil.

In the video, William Waack, an anchorman for Brazil’s largest television network, Globo, was preparing for a live shot with a guest, with the White House in the background, while covering the presidential campaign in the United States.

In response to loud honking from a nearby car, Mr. Waack said under his breath, “It’s a black thing. No doubt,” and laughed about it with his guest.

Reaction on social media was swift and indignant after the video started to circulate.

By Wednesday evening, #ÉCoisaDePreto — Portuguese for “It’s a black thing” — was one of the top trending topics on Twitter in Brazil.

The same day, shortly before Mr. Waack was scheduled to anchor a news show, Globo announced that it had “removed” Mr. Waack until the situation could be clarified.

“Globo is viscerally opposed to racism in all of its forms,” the company said in a statement, adding that Mr. Waack had made comments that “everything indicates were of a racist nature.”

The video was leaked by a former video editor for Globo, who said he was appalled by the remarks at the time but was afraid he could lose his job if he released the video to the public.

The video editor, Diego Rocha Pereira, who no longer works for the network, said he had heard the comments as he sat in the network’s control room.

“I rewound the video to be sure, I couldn’t believe he would have said that,” he told the Jovem Pan radio station. “I was so disgusted, I recorded it on my cellphone.”

Mr. Waack has not publicly responded. In its statement, Globo said, “Waack affirms he doesn’t remember what he said, given that the audio is not clear, but he offers sincere apologies to those who feel they have been offended.”

On social media, the remark has been turned into a campaign, shining a light on the accomplishments of famous black Brazilians like the 19th-century novelist and poet Machado de Assis, as well as global leaders, including Nelson Mandela, and sports stars and artists.

Many people have written on Twitter about their own struggles in a country with a long history of slavery and racism. One person wrote: “#It’sABlackThing my mother, a black, single woman, raising 7 children without the help of a white man (my father).”

Brazil was the last country in the Americas to abolish slavery, in 1888. Over three centuries, some four million Africans were brought here and forced to work in fields, mines and private homes.

Today, just over 50 percent of Brazilians identify as black or biracial, and many Brazilians say there is a racial harmony here that does not exist in the United States.

But others say the figures point to a different reality — Brazil is a country where the life expectancy of black men is considerably lower than for their white counterparts, and where people of African descent earn 36 percent less than nonblack Brazilians.

In recent years, Globo and other television networks have used their powerful positions to combat racism with more prominent roles for black Brazilians on soap operas and reality TV shows.

When Brazil’s first black weather broadcaster on a prime-time news broadcast — Maria Júlia Coutinho, known widely by her nickname, Maju — was subjected to abuse, her colleagues at Globo promoted the #WeAreAllMaju campaign.

In the case of Mr. Waack, a veteran journalist who gained the respect of his colleagues over the years with his coverage of the fall of the Berlin Wall and numerous conflicts in the Middle East, Globo said it was in talks with him about what would happen next.