A veteran air-traffic controller at the facility that handles flights in and out of Newark Liberty International Airport is calling for more resources and speaking out about the intense pressures workers face amid a staffing shortage and tech outages.

Jonathan Stewart was badly shaken by a recent close call in airspace around Newark, N.J. “I don’t want to be responsible for killing 400 people,” he said in an interview.

The FAA is proposing to temporarily reduce the number of flights landing at Newark Airport in an effort to curb widespread delays.