A Milwaukee man whose ill-timed bathroom break on a Delta flight in April grabbed headlines after his subsequent removal was caught on cellphone cameras has sued the airline claiming racial discrimination.

In a complaint filed Tuesday in Wisconsin federal court, Kima Hamilton, who is black, alleges that Delta Air Lines wouldn't have violated his civil rights and booted him from the Milwaukee-bound flight if he were white.

The incident began when Hamilton's plane was delayed on an airport tarmac in Atlanta. According to the 40-year-old art teacher, he desperately needed to use the bathroom and knew that announcements asked passengers to remain seated.

While the lavatory was steps away, a flight attendant stopped him before he could get to it and told him that if he went, the pilot would have to be alerted and the plane would lose its place in line for takeoff.

But Hamilton couldn't bear another seven- to 10-minute delay, he said, and was "experiencing an emergency." Again, he said, he was warned about getting up.

Related: Delta asked man to leave flight after using restroom, videos show

"At this point, Hamilton had to make a literal choice between relieving himself in the lavatory or in his clothing," according to the suit. He chose the former — taking about 30 seconds in the restroom, the suit adds.

That set off a chain of events that led the plane to return to the gate to have Hamilton removed.

Other passengers used their cellphones to capture employees talking to Hamilton, who was frustrated and could be heard asking why he had to be taken off.

"Mr. Hamilton was never confrontational. He was very polite. He only asked for clarification throughout," passenger Michael Rosolino told NBC affiliate WTMJ.

Hamilton's lawsuit said other similar incidents have occurred involving white passengers who were allowed to remain on their flights. His case was one that followed heightened scrutiny over passengers being kicked off airplanes for various reasons.

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Delta said in a statement at the time that their flight crews are "extensively trained to ensure the safety and security of all customers."

The cost of half of Hamilton's flight was subsequently refunded, but he had to pay triple to book a new ticket home, he said.

His lawsuit is seeking unspecified compensatory and punitive damages. His attorney could not be immediately reached for further comment Thursday.

Delta said in a statement that it is "imperative" that passengers comply with crew instructions "during all phases of flight, especially at the critical points of takeoff and landing, which our findings indicate this customer did not do."

The airline said it takes claims of discrimination seriously, but declined to comment further citing pending litigation.