Members of a labor union joined family, clergy, community members and public officials at a vigil Thursday afternoon to mourn the death of a construction worker who died earlier this month at a Jersey City work site — and also to call attention to illegal workplace hazards. Juan Jose Coc, a 40-year-old married father of one, fell four stories to his death at a Communipaw Avenue construction site on Feb. 2. Near the conclusion of the vigil, attendees lit candles and a roll call was read of 30 incidents in Jersey City in which a worker was either seriously injured or killed on the job. “While mu…