WASHINGTON — The Department of Homeland Security is the worst large federal agency to work for, according to an employee survey released Tuesday.

The department came in 19th out of 19 in the Partnership for Public Service poll. NASA was ranked the best workplace.

The problems at Homeland ­Security appear to be bureaucratic rather than linked to the stressful nature of the work. Scores have been consistently low on morale, leadership and pay, and frequent leadership turnover has been an issue.

“I’m disappointed,” Homeland Security Secretary Jeh Johnson said.