Thousands of construction workers in the city took time Monday to remember their fallen colleagues at a mass at St. Patrick's Cathedral at the start of the fourth annual Construction Safety Week.

The ceremony honored the 13 people killed in construction accidents this year, including the seven people who died in last month's crane collapse in Turtle Bay. The names of the lost workers were read and each was represented by a hard hat and a flower.

Six construction workers died in the crane collapse, making it the worst single loss of construction workers since the September 11th terrorist attacks.

Earlier this month, a 25-year-old worker died after falling seven stories while working on an Upper East Side highrise.

Events will be held around the five boroughs for safety week.

The acting buildings commissioner is holding free seminars for workers on the practices and safety standards they are entitled to.

"What we're hoping to do is either raise the level of standards, get to the worker," said Acting Buildings Commissioner Robert LiMandri, "or have the Department of Buildings, or Occupational Safety and Health Administration work in a different scenario, utilizing and pushing our training effort, or actually changing regulations and requirements."

Gregorio Dominguez was among the day laborers who turned out at an immigrant advocacy center in Port Richmond, Staten Island Monday to learn his rights when working at a construction site. Dominguez said his life was saved twice by a safety harness — which he only got after another worker, who hadn’t been given one, fell several floors.

"You basically work with fear all the time," he said. "We were working with a machine, breaking brick and pouring it, when one of the workers fell. We were kind of relieved because boss then gave us harnesses."

Mike Yarnell, a compliance assistance specialist for OSHA, said it is surprising how many workers are just like Dominguez.

"Back in December we had an outreach session and I brought in a body harness and most of them had never seen it before, didn't have a clue on how to put it on," said Yarnell.

Officials have pledged more than $4 million to step up inspections of high-risk construction sites and improve worker training.

Last week, Department of Buildings Commissioner Patricia Lancaster stepped down after Mayor Michael Bloomberg openly criticized her agency.