The poster prompted outrage on social media after Twitter user John Sawyer posted a photo of it, asking Red Cross to send a different one to the recreation center in Salida, Colo.

Some users failed to see what was racist about the poster, calling it another example of political correctness gone awry. Others noticed some controversial details upon closer inspection.

Twitter user Rob Ullman, who claims to have created the original illustration for Red Cross that was later changed, tweeted, "My version is many things, but I don't believe it's racist."

The organization Black Kids Swim told the Washington Post there is a history of discrimination against black children at public pools that makes them less likely to take up swimming. As a result, drowning rates for black children are significantly higher than those for white children. Last year, a Texas police officer resigned after video was released showing his response to black youth gathered at a pool party. The white police officer was recorded pushing a black, bikini-clad teenage girl to the ground and kneeling on her back.

In its published apology, the American Red Cross says it is working to reduce the drowning rate in high-risk communities by teaching more children and adults to swim. "With this campaign, we are focusing on areas with higher-than-average drowning rates and participants who otherwise wouldn't have the opportunity to take swim lessons."