The driver of a passenger van mangled in a devastating southwestern Ontario crash that ended in multiple deaths was not legally licensed to drive the oversized vehicle, provincial police said on Wednesday.

The driver, who was among the 11 people killed in Monday's crash, did not brake at a stop sign and failed to yield to traffic with the right of way, OPP Insp. Scott Lawson said on Wednesday.

"It was this action that caused the collision," Lawson told a news conference.

Provincial police continue to investigate the circumstances that led to a devastating crash that killed 11 people and left another three in hospital.

A flatbed truck and a 2007 GMC Savana passenger van collided shortly before 5 p.m. on Monday at an intersection in Hampstead, Ont., northeast of Stratford.

Ten people inside the van, all migrant workers from Peru, and the 38-year-old truck driver were killed in the crash.

"This crash should cause all Ontarians to pause and seriously consider their own driving habits and change them for the better immediately," OPP Insp. Steve Porter told reporters.

On Wednesday, investigators released the names of the 13 migrant workers – all from Peru – involved in the crash, identifying David Armando Blancas-Hernandez as the driver.

The 45-year-old held an Ontario licence to legally drive common vehicles, but did not hold the Class F licence needed to operate the 15-passenger van involved in the crash.

On Wednesday, OPP released the names of the migrant workers killed and injured in the crash:

  • David Armando Blancas-Hernandez, 45
  • Jose Mercedes Valdiviezeo-Taboa, 49
  • Cesar Augusto Sanchez-Palacios, 53
  • Enrique Arturo Leon, 47
  • Corsino Jaramillo, 47
  • Mario Abril, 48
  • Oscar Compomanes-Corzo, age unknown
  • Juan Castillo, age unknown
  • Elvio Bravo-Suncion, age unknown
  • Fernando Correa, age unknown

Edgar Sulla-Puma, 26, was injured in the crash and remains in hospital in fair condition.

Juan Ariza, 35, and Aberlardo Alba-Medina, 38, remain in hospital in critical condition. The workers, all from Peru, had been living in Canada and working at a poultry farm vaccinating chickens near the crash site.

Several grieving family members gathered at the crash site on Tuesday, tearfully laying down flower bouquets and comforting one another near tire tracks left marking the fatal crash.

A prayer vigil for the crash victims will be held at a nearby church later this week. The non-denominational service is scheduled for 7 p.m. on Friday at St. Joseph Catholic Church in Stratford.

The Diocese of London says the service is to remember the victims of the crash and their families as well as to show appreciation for emergency personnel.

Police and EMS workers on the scene said the crash was so severe that it was a "miracle" that anyone had survived.

Transportation Minister Bob Chiarelli said on Tuesday that all the facts surrounding the crash must be examined

"It's not a clear-cut accident, obviously, with one stop sign and one through street," Chiarelli told reporters Tuesday. "So we need to look at the facts.

"It is so serious, it is so severe and it is so sad really that this thing can still happen, that we've got to be so comprehensive that we do everything possible to ensure that it never happens again."

There are reports that some of the victims had only recently arrived in Canada, but officials said Tuesday some had been living here for years.

Christopher Fulton, of London, was driving the truck involved in the crash and was also pronounced dead at the scene.

His employer, Speedy Transport CEO Jared Martin, said Fulton was celebrating his 11th wedding anniversary on the day of the crash.