Family and friends of four construction workers who were killed on Christmas Eve in a tragic accident will gather Thursday evening to remember the men with a candlelight vigil.

The vigil will be held at the site of the accident -- an apartment building at 2757 Kipling Avenue -- at 7 p.m.

The vigil will also be held in support of a fifth construction worker, 21-year-old Dilshod Mamurov, who suffered serious injuries as a result of the accident.

Mamurov was working on an elevated "swing-stage" type of scaffold repairing balconies with the four men when the structure broke in half, sending the men tumbling down 13 storeys.

Ukrainian national Aleksey Blumberg, 22 of Ukraine, Alexander Bondorev, 25 of Latvia and Vladimir Korostin, 40, and Fayzullo Fazilov, 31, both of Uzbekistan, were pronounced dead at the scene.

Mamurov suffered a broken spine and two fractured legs.

The accident is considered the worst one-day workplace tragedy in 50 years, since five men were trapped and killed while working in an underground tunnel in 1960.

The men who were killed on Christmas Eve were working in Canada but were not permanent residents.

The vigil is being organized two groups called "No One is Illegal" and "Justice for Migrant Workers." 

The organization said in a news release Tuesday that these workers who do not have a permanent resident status are often not protected by Canadian laws.

"Workers without full status do the hardest, most dangerous work yet receive the least protection under existing laws," the news release says. "Workers asserting their rights or demanding less dangerous working conditions are rarely able to switch jobs and risk deportation for speaking out."

There is speculation that the workers were not wearing full body harnesses when the scaffolding broke -- a clear violation of workplace regulations.

"Though there are strict regulations for most work, including swing stages, workers without full status are unable to assert these rights. No one is supposed to work on one without a training certificate," said Jim Nugent, an organizer with No One Is Illegal -- Toronto and a construction worker for thirty years.

"Every worker has to be supplied with a full body harness and his/her own lifeline. These regulations were blatantly broken because employers know that there is no support for workers without full status," he said.

The workers' family and friends have asked for a public inquiry into the incident.