The city’s transit union, whose contract expired in January, broke its promise not to negotiate in the press by accusing the MTA of putting the public at “risk” with plans to hire more part-time bus drivers, said agency head Joseph Lhota.

Part-timers would cause accidents because they might be fatigued from holding multiple jobs, said TWU Local 100 President John Samuelsen.

Samuelsen, in a letter published onthe Huffington Post Web site, said Lhota wants to eliminate conductors on some full-length trains, not just shuttles and the G line.