The toxicologist described butane as an asphyxiant that can be found in aerosol cans, cigarette lighter fluid, butane cans or LPG canisters.
Mrs Rarere-Mischefski had been with her husband for about six years, he was shocked at post-mortem results, he did not know she engaged in that behaviour.
During an inquiry into her death it emerged that she "inhaled/abused substances" as a teenager.
The reposrt stated a close relative said Mrs Rarere-Mischefski suffered post-natal depression after having her two children and there was an incident where she sniffed petrol.
The relative said Mrs Rarere-Mischefski was secretive about her substance abuse.
At the scene there was nothing to suggest she had died from butane inhalation, but pathologists said this was not unusual as the effects of butane could emerge after a period of time since using the solvent had lapsed.
"Accordingly, she may well have had time to conceal the evidence of her actions," the report stated.
Mrs Rarere-Mischefski had been diagnosed with a mental illnes in 2013, she was prescribed medication and referred to mental health services.
Despite having a good childhood in Wairoa with her five siblings the last few years of her life were described as "challenging'.
Her mother had died in 2008 and her father in 2009, she suffered post natal depression, had her house broken into and her car stolen.
She had experienced suicidal thoughts but had never intended to act upon them.
While her marriage had difficult patches the couple were living together at the time of her death and were supported by her mother-in-law.
She had also been attending a Diploma of Beauty and Body Therapy course at Eastern Institute of Technology.
On the Saturday afternoon, hours before her death, the couple had played netball, Mrs Rarere-Mischefski's mother-in-law had then taken her and the kids children to McDonalds, to join her husband for dinner during his work-break.
Her mother-in-law was the last person to see her before she died, she said: "Arahia was talking fine, walking fine there was nothing wrong at all with her that I could tell of."
She had sent a number of "quite normal" text messages to relatives in the course of that Saturday evening, all were related to "catching up" and what she was doing.
She text her mother-in-law, inviting her to dinner the following night, the last text she sent was to her sister-in-law, her husband sent her a text at 9.46pm.
When he got home he found the message unopened, his wife's phone still plugged in and charging.
The Coroner said despite having suicidal thoughts Mrs Rarere-Mischefski had inhaled the butane without the intention of dying.
"Arahia was found right beside the dead bolted sliding door to outside, and the curtain was pulled back about 30c. This suggests she have been trying to get out o fresh air, realising she was badly affected by the butane, but this is conjecture and cannot be known with certainty."
"I note that the finding of butane in her system came as a shock to those closest to Arahia."
She noted it was possible that her inhalation of butane that evening was the first time she had done it in years.
Where to get help
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
If it is an emergency and you feel like you or someone else is at risk, call 111.
