A man who did not learn his son had died huffing butane until several months after the tragedy has condemned the practice as evil.
He has joined calls for a bigger focus on huffing - now the subject of an urgent review after a recent death linked to the practice and an explosion that nearly killed two Mosgiel teenagers.
Yesterday, a coroner's inquest heard that the father of a 16-year-old Rotorua boy knew nothing of his son's use of butane before his death last year.
At the request of the family, coroner Wallace Bain suppressed the boy's name and date of death, but allowed the events leading up to his death to be made public.
The boy - described as a "highly intelligent person with superior-problem solving skills" - spent his last night sitting in front of a laptop computer in the lounge as his father watched cricket on television.
As he went to bed around 12.30am, he told his father he would see him in the morning, when they planned to travel to Tauranga to play bridge.
His father found him lying in bed the next morning, unresponsive to the alarm and cellphone loudly blaring.
Tidying his son's room shortly after his funeral, he found among his clothes an empty deodorant can he had bought him just eight days before. It usually took his son about a month to go through a can.
An autopsy exam later found the teenager's brain was 25 per cent heavier than expected.
The inhalation of butane found in his lungs triggered a fatal cardiac arrest.
But his father said his son had shown no signs of using the chemical - and agreed with police comments that there needed to be more awareness for young people about huffing.
"They just don't realise you die from that."
Huffing is thought to have caused about 50 deaths since 2000.
National Poisons Centre toxicologist Dr Leo Schep said butane gas products were popular among young people as they were easy to obtain, simple to hide and "an easy way to get high".
Huffing-related calls to the centre suggested the peak age of inhalant use was between 13and 15 years old.
Prime Minister John Key said he would look at the report from the chief coroner and consider stricter controls on sales of butane gas.
Drug experts said yesterday that the issue was difficult to tackle because of the easy access to products and the risks of publicising it resulting in more people trying it.
* Chemical smell on the breath or clothing.
* Empty aerosol, butane or glue containers left where the child has been.
* Drunken behaviour such as a dazed or dizzy appearance, where consumption of alcohol is an unlikely explanation.
* Suddenly mixing with a new group of friends, especially if they hang out in secluded places.
* Unusual mood swings or a general change in behaviour.
* Alterations in sleeping patterns or eating behaviour.
* A persistently runny nose or eye irritation.
Source: New Zealand National Poisons Centre