Image credit: Brett Coomer/Houston Chronicle/AP Photo

Nikki Araguz, a transgender widow of a firefighter, is suing the City of Wharton, Texas for workers' compensation benefits that she was denied because she was born a man.

Araguz, 36, legally changed her name in 1996 from Justin Graham Purdue. In 2008, she married Thomas Araguz, a Wharton County volunteer firefighter, and she underwent sexual reassignment surgery later that year.

Thomas Araguz was killed while fighting a fire in July 2010.

After losing her appeal to workers' compensation benefits last month in the state's administrative process, Araguz filed a suit last week against Wharton, about 60 miles outside Houston with a population of over 9,000 people.

A judge voided Araguz's marriage last year and denied her death benefits because the state of Texas does not recognize same-sex marriages. She filed an appeal last month.

"As difficult as this has been for me in my grief, I cannot in good conscience allow someone else to go through this again," Araguz said.

See the previous 20/20 story about Nikki Araguz.

Living in Houston, Araguz said she is a public speaker and activist, working with transgender youth, adults, and children and spouses of transgender people.

"I can't imagine being known as the woman who walked away from this," she said, referring to her legal suits.

Araguz said she is also finishing a book and her second documentary.

Her attorney, Peggy Campbell of Peggy M Campbell Esq. PC in Houston, said Araguz' recent suit against the city for workers' benefits is not about gay marriage.

"All of the courts keep saying they don't allow gay marriage," Campbell said. "Our position is that this is not a gay marriage issue. It's a man being married to a woman."

Robert Stokes, attorney for the city of Wharton declined to comment due to the pending litigation.

Campbell said that if the suit succeeds, Araguz should be entitled to a weekly benefit for the rest of her life, or until she re-marries, which would allow her 104 weeks in a lump sum. Campbell declined to provide the value of the benefit.