 Díaz has legislated on behalf of Brownfield Cleanup and Green Roof Tax Abatement, worked to restore the Bronx River which runs through the 85th Assembly District, and opposed environmental racism.In September 2007, he was named one of "City Hall"'s "40 under 40" for being a young influential member of New York City politics.On February 4, 1999, Amadou Diallo, a young African immigrant, was killed by four New York City police officers who fired 41 unanswered rounds at him.