NEW YORK (WABC) -- Former Rep. Carolyn McCarthy, who became a leading voice for gun control when she ran for Congress following the 1993 LIRR massacre, has died. She was 81.

McCarthy entered politics in the wake of the December 1993 shooting on the LIRR by gunman Colin Ferguson that killed six people, including her husband, Dennis, and injured 19, including her son, Kevin, who was shot in the head but survived.

McCarthy became a fierce gun control advocate, despite publicly supporting the Second Amendment, taking the lead after the Columbine High School shooting in 1999, the Virginia Tech shooting in 2007 and the Sandy Hook shooting.

She helped strengthen background checks on gun buyers, childproof gun triggers, and disqualify those with mental health conditions and criminal records from purchasing firearms.

She served 18 years in the House before announcing in June 2013 that she was being treated for lung cancer and retired from Congress the next year.

She beat cancer and moved to Florida for her final years.

Gov. Kathy Hochul has directed flags on all state government buildings to be flown at half-staff in honor of McCarthy.

"Representative Carolyn Maloney was a strong advocate for gun control and an even more fierce leader," Governor Hochul said. "From her days as a Congresswoman to advocacy, Carolyn McCarthy touched the lives of many through her work in public service, and I join her family, loved ones and Long Islanders in mourning this loss."