IndyCar driver Justin Wilson died from a head injury suffered when a piece of debris struck him at Pocono Raceway, the series announced Monday night.IndyCar made the announcement at Indianapolis Motor Speedway.IndyCar has had its share of safety issues in 2015 that began when a woman was hit by debris at the season-opening Grand Prix of St. Petersburg.Wilson, 37, was hit in the head during Sunday's race in Long Pond, Pa., by a piece of debris that had broken off the car of Sage Karam, who spun and hit the wall while leading on Lap 180 of 200. The nose cone came off of Karam's car and, after flying over several passing cars, struck Wilson's helmet.Wilson's car veered into an interior wall at the track, and he was taken by helicopter to Lehigh Valley Health Network Cedar Crest Hospital in nearby Allentown."Can't even begin to describe the loss I feel right now. He was my Brother, my best friend, my role model and mentor. He was a champion!" his younger brother, Stefan, also a racer, tweeted. Stefan Wilson said his brother's organs would be donated."This is a monumentally sad day for IndyCar and the motorsports community as a whole," said Mark Miles, CEO of Hulman & Co., which owns IMS and IndyCar. "Justin's elite ability to drive a race car was matched by his unwavering kindness, character and humility — which is what made him one of the most respected members of the paddock."The last IndyCar driver to die in an on-track incident was two-time Indianapolis 500 champion and St. Petersburg resident Dan Wheldon, another popular driver who was killed in the 2011 season finale at Las Vegas after his head hit a post when his car went airborne.Holly Wheldon, his sister, tweeted Monday night: "May these two gorgeous British boys rest in peace together.''Wilson, who also drove in Formula One, earned seven victories in major North American open-wheel series, four in Champ Car and three in IndyCar. He had 12 career podiums in IndyCar including runnerup finishes at the Grand Prix of St. Petersburg in 2009 and 2010.Wilson's friends and rivals in the IndyCar series responded to his death with an outpouring on social media."A lot of drivers are great because they're selfish," IndyCar driver Graham Rahal, Wilson's Champ car teammate in 2008, told the Indianapolis Star . "But Justin was always the first guy to come up to me and say something positive, something constructive, something helpful. You mention 'team player,' that's Justin, and it's hard to find that sort of guy in sports. He was just the nicest guy out there."Brigitte Hoffstetter, who was hit by debris on March 29 during the St. Petersburg race, said in a lawsuit filed against IndyCar that her skull was fractured. She was in the concession area when debris sailed over the grandstand. IndyCar made a series of rule changes to fortify the many parts and pieces on its new aerodynamic body kits, but the nose that flew off of Karam's car is not a tethered part. The series also took action after three cars went airborne during practices for the Indianapolis 500.Shortly after Sunday's race, the accident had reignited the debate about open cockpits. In addition to Wheldon's death, IndyCar driver James Hinchcliffe was concussed last year when debris hit him during the road race at Indianapolis.Wilson was part of a three-driver council in IndyCar, which was created to address safety concerns after Wheldon's death.The most common safety suggestion is a canopy over cockpits, like in fighter jets. But purists don't want to see such radical change to the car, and there are questions about whether canopies would hamper visibility and become a barrier to a quick escape from the car.Wilson, a native of Sheffield, England living in Colorado, entered this season without a full-time ride. He latched on with Andretti Autosport and was in the sixth of seven scheduled races with the team. The season concludes Sunday in Sonoma, Calif."While Justin was only part of the Andretti lineup for a short time, it only took a second for him to forever become part of the Andretti family," the team said. "His life and racing career is a story of class and passion surpassed by none."Wilson was popular among peers and made many fans off the track with his support of foundations related to dyslexia. Wilson was dyslexic.He is survived by wife Julia and daughters Jane and Jessica. Donations can be sent to Wilson Children's Fund, C/O IndyCar, 4551 West 16th Street, Indianapolis, IN 46222.