Amid one of the worst outbreaks of West Nile virus ever seen in the U.S., officials in the Dallas area of north Texas have declared war, launching all-out chemical warfare on mosquitoes.

Airplanes took off from Executive Airport on Thursday night, flying at about 300 feet and covering numerous communities with pesticide — for the first time since 1966. They were called back after several hours due to an incoming storm, but at a press conference on Friday officials said they planned to resume spraying again at dusk, weather permitting.

The Centers for Disease Control said that of the nearly 700 cases of West Nile virus infection recorded across the U.S. in 2012, over half have occurred in Texas. So far, 17 have died in the Dallas area alone.

CBS Dallas said that officials plan to coat nearly all of Dallas and several nearby cities in pesticide to break an alarmingly rapid spread of West Nile. Additional cities are in discussions to join the effort as soon as permits can be issued. The air space around former President George W. Bush’s home, however, was excluded from spraying.