Anthony Chester watched his son battle an addiction for years, a fatal illness that began with oxycontin and ended with heroin on July 28.

"He was in such pain, emotional and physical pain," Chester said of his son's struggle.

Tyler Marshall was 31 when he died of the suspected overdose inside a construction site in Toronto. And his death comes amid a spate of fatal overdoses this summer — something that propelled the city to speed up the launch of its supervised injection sites.

Too late, however, for Marshall.

That's partly why his father is calling on all levels of government to do more to help those, like his son, who struggle.

"He was a good, good person," Chester said, fighting back tears. "Regardless of the choices he made, good or bad he still didn't deserve to end up dead in a construction site. Nobody deserves that."

Anthony Chester believes his son could still be alive if he had access to prescription heroin instead of having to buy drugs on the street to feed his addiction. (Dean Gariepy/CBC News)

Chester said he believes his son went to a different dealer to get heroin, which turned out to have a fatal mix.

"The coroner said he had 40 times the lethal limit of fentanyl in his system."

Chester said the family was told that information in a phone call, but he has not yet received the full autopsy report.

Toronto police issued a public warning about the possibility of contaminated heroin laced with fentanyl that week, a batch they connected to four drug deaths and 20 other overdoses.

Police were unable to confirm whether Marshall's death was counted among those numbers.

How did he get hooked?

Looking back on his son's childhood Chester remembers that his "Tyler was every father's dream."

The son of two teachers, Marshall's inquisitive nature and athletic abilities made his parents proud.

He was a great big brother, adored by his two younger sisters.

But when he was 14, the boy was sent to live with his godmother in British Columbia to keep him out of trouble.

Tyler Marshall was a teenager living in British Columbia when this picture was taken. He returned to Toronto at 19, broken by the end of a four-year relationship, his father says. (Anthony Chester)

He came back to Ontario at 19 after he and his girlfriend of four years broke up, his father said.

"When he came home he was really shattered."

Then Marshall started experiencing dental pain. He had a fear of going to see a dentist, his father said, so Marshall turned instead "to oxycontin, the pills."

Then he turned to heroin.

A fall from a third-floor window that shattered the bones in his hands worsened Marshall's addiction, Chester said. He lost his spleen in the accident as well.

Marshall's life took on a cycle, a wheel that he stayed on for years.

He would go to detox to try to get clean, visit the methadone clinic and even spent a stint at a rehabilitation centre. Eventually, he would relapse, Chester said.

But what Marshall's father most wants people to understand is that what happened to his son "can happen to anybody."

Asking for help

Both parents believe that if their son had been granted access to prescription heroin, he might still be alive. That's something, however, that's not yet available in Toronto.

The city's associate medical officer of health, however, noted that "there's definitely interest and a need for it here."

Dr. Rita Shahin said that while prescription heroin and hydromorphone is legal in Canada and available in Vancouver, the focus in this city right now is on opening permanent supervised injection sites.

She noted, however, that the Vancouver clinic and those in Europe that have offered the prescription heroin have seen some success in cases where traditional treatments have failed.

Patients in those cases "have more success in terms of stabilizing their lives [and are] less likely to be involved in crime."

Chester said he hopes that by sharing his son's story — and his family's heartbreak — those struggling with the pain of addiction will see that they're not alone.

The grieving father said he is finding some comfort in knowing his son is no longer in pain.

And he keeps reliving the last time he saw Marshall, the morning before his death.

Chester said he begged his son to return to the hospital, but Marshall just cracked a couple of jokes and left his father with a few words as he walked out the door.

"See you later pop," he said. "Love ya."