Thousands were poisoned by Flint’s drinking water. Matt McFarland, a foreman at Flint’s water treatment plant, tried to sound the alarm, a new FRONTLINE documentary exclusively reveals. Subscribe on YouTube: bit.ly/1BycsJW “I remember specifically, the day before they actually flipped the switch, he called me and he said, ‘Tonja, contact everyone that you know in Flint, anybody you care about, and tell them, do not drink the water,’” Tonja Petrella, his sister, told FRONTLINE. Petrella said that McFarland cautioned, “It’s not safe. We’re not ready,” and finally warned: “People are gonna die.” McFarland passed away in 2016. But in an exclusive interview for the upcoming FRONTLINE investigation "Flint’s Deadly Water," Petrella spoke publicly for the first time about the concerns her brother shared in the run-up to the water switch. “He would call me and he would just be so upset … I mean, he knew that they weren’t ready for this,” Petrella says in the above excerpt from the FRONTLINE film. Tune In or Stream "Flint's Deadly Water" starting Sept. 10, 2019: to.pbs.org/2NktVDu Twitter: twitter.com/frontlinepbs Facebook: www.facebook.com/frontline Google+: plus.google.com/+frontline/posts FRONTLINE is streaming more than 200 documentaries online, for free, here: to.pbs.org/hxRvQP You can also tune in or stream on the PBS Video App: www.pbs.org/pbs-video-app/ Funding for FRONTLINE is provided through the support of PBS viewers and by the Corporation for Public Broadcasting. Major funding for FRONTLINE is provided by the John D. and Catherine T. MacArthur Foundation and the Ford Foundation. Additional funding is provided by the Abrams Foundation, the Park Foundation, The John and Helen Glessner Family Trust, and the FRONTLINE Journalism Fund with major support from Jon and Jo Ann Hagler on behalf of the Jon L. Hagler Foundation.