The 29-year-old man charged in a crash north of Toronto that left four people dead is one of the heirs to a construction empire.

Marco Muzzo is facing 18 charges as a result of a crash in Vaughan, Ont. on Sunday. Three children and their grandfather were fatally injured in the collision.

Muzzo has been charged with four counts each of impaired driving causing death, driving with a blood-alcohol level of over 80 (more than 80 milligrams of alcohol per 100 millilitres of blood) causing death and dangerous operation of a motor vehicle causing death.

He has also been charged with two counts each of impaired driving causing bodily harm, driving with a blood-alcohol level of over 80 causing bodily harm and dangerous operation of a motor vehicle causing bodily harm. Sources told CTV Toronto's Tamara Cherry that Muzzo took two breath tests after the crash, and allegedly both times, blew more than twice the legal limit of 80 milligrams in both tests.

According to sources, preliminary investigation suggests Muzzo allegedly ran a stop sign and T-boned the minivan, which then hit a third vehicle. The allegations have not been proven in court.

Muzzo is part of a family that owns a construction empire estimated to be worth more than $1 billion. The family owns Marel Contractors, based in Vaughan, Ont., which operates in Toronto, Ottawa, Calgary and southwestern Ontario.

The family also owns Pemberton Group, one of Toronto's biggest development companies, which has been in operation since 1965. Pemberton builds condominiums and commercial developments across the Greater Toronto Area.

The companies were founded by Muzzo's late grandfather, also named Marco Muzzo, in the 1950 and 1960s. In January 2015, the late grandfather's estate was worth $1,772,089,479, according to Canadian Business' annual ranking of Canada's richest people. 

The family has also contributed millions of dollars to fund various treatment centres in Toronto hospitals. They host an annual fundraiser called Motoamore, which raises money for the Muzzo Family Surgical Innovation Fund at the University Health Network. Donors who attend the event are given the chance to drive their vehicles along the Canadian Tire Motorsport Park (formerly called Mosport International Raceway), a NASCAR and stock car track in Bowmanville.

Sources told CTV Toronto that Muzzo was planning to get married next month.