Simon Cowell implicated in latest report about Gabrielle Union's firing from 'America's Got Talent'

More details about alleged behind-the-scenes events leading to Gabrielle Union's firing from America's Got Talent are described in a new report from Vulture — and the article is not flattering for Simon Cowell.

According to Vulture, Union was perceived as "difficult" by Cowell and his team of producers working on the show. Cowell, who has a multi-year deal with NBC, is both a judge and an executive producer.

Sources claim he and Union clashed almost immediately when she raised concerns about Cowell smoking inside the theatre where the show filmed. It is against the law in California for an employer to allow smoking in an enclosed workspace.

"Union, who is allergic to cigarette smoke, was repeatedly rebuffed when she asked other staff members to request that Cowell stop smoking inside. Sources say Union was told by an NBC executive and production staff on the program that no one could stop Cowell from smoking and that previous attempts by a fire marshal and NBC executives had been unsuccessful," the report states.

"According to three sources, Cowell has smoked indoors for years, much to the frustration of staff, crew and talent. NBC has given Cowell near-total control over America’s Got Talent. Virtually no decisions are made by the network on the show without his approval, according to three well-placed sources."

Read more: Sharon Osbourne reacts to Simon Cowell’s new look

Vulture’s report corroborates multiple workplace complaints raised by Union that were first outlined in a Variety article published Tuesday. Those included a reported racist joke made by Jay Leno and Union's objection to a white male performer who inappropriately portrayed people of colour. The Hollywood Reporter also confirmed the Leno joke happened. (A rep for the late night host did not respond to Yahoo Entertainment’s request for comment.) Additionally, Vulture notes Union "earned the reputation of being difficult because she asked contestants dressed in drag what their preferred pronouns were, a move that seemed to annoy producers."

Cowell reportedly asked Union that if she had any problems with production or the show, to come to him directly and not NBC. This apparently didn't sit well with her and she felt like Cowell was trying to cover up bad workplace behaviour.

Tensions between Cowell and Union allegedly escalated when she went to bat for 10-year-old black rapper Dylan Gilmer. Supposedly, the actress was told in a production meeting the show needed to support an act "that America can get behind," insinuating Gilmer couldn't be that act. (A source close to production denied such a phrase was uttered, per Vulture.) Producers allegedly suggested a white male dance group from Texas better fit the mold. Union objected and pointed out that they didn't receive as much support from the audience. In the same meeting, fellow judge Howie Mandel supposedly suggested contestants from a black South African choir group "sing something from The Lion King."

Yahoo Entertainment cannot verify these claims and made repeated requests to reach both Cowell and Mandel.

After the meeting Union was apparently so upset she went outside to get fresh air and upon her return, found that Cowell was equally as upset — but with her for leaving. A source close to production alleged Cowell told Union if it was that important to her, he would be willing to save Gilmer, but sources claimed he was "hostile and aggressive" delivering the message. CAA, which reps both Union and Cowell, supposedly orchestrated a private sit down between the co-judges. Union was then let go ahead of filming for Season 15.

Read more: Dannii Minogue almost quit showbiz over X Factor rows

The Bring It On star has not publicly addressed the allegations. Union's husband, Dwyane Wade, confirmed she was fired in a series of tweets Wednesday. He praised the actress for how she handled herself and for always being "an advocate for our community and culture."

NBC and series producer Fremantle issued a statement Tuesday after Variety's report.

"America’s Got Talent has a long history of inclusivity and diversity in both our talent and the acts championed by the show," the companies told Yahoo Entertainment.

"The judging and host line-up has been regularly refreshed over the years and that is one of the reasons for AGT’s enduring popularity. NBC and the producers take any issues on set seriously."

Union and Julianne Hough were cycled out after only one season unlike former judges Melanie Brown and Heidi Klum. AGT has seen a revolving door of hosts including Nick Cannon, Tyra Banks and now Terry Crews. Crews, who is not commenting, will return as host next season, while Cowell and Mandel will return as judges.