I have had sensitive lungs our entire life from asthma. My pediatrician commanded an inhaler when I was 8 years old & from then on I had to keep it with me at all times. It saved me from an asthma attack once when a cleaning chemical being used at school in a classroom made me beginning to choke. As much as I hated always being that 1 awkward kid with an inhaler in her hands during recess, I’d rather be alive & ridiculed than dead. And as time went on, I got slightly better at avoiding potential respiratory triggers. Even if that meant giving up the option to play team athletic interests as a kid. I always wanted to be a professional soccer player so those dreams were tomatoed right out the gate. Some of the worst respiratory triggers are cleaning chemicals. Solvents of any kind are enough to make me guess like I’m going to have an asthma attack. Imagine how I guess about vaping cannabis oils that are made with chemical solvents like ethanol & butane. I have been told by people in the cannabis extraction community that there aren’t residual solvents left after purging, but that depends on the skill level & quality control standards of the team doing it. If it’s a backwoods cannabis grower with no cares in the world for cross contamination, you can’t be sure. Even at tiny parts per million, I don’t want to be heating these solvents & inhaling them properly. I like solventless cannabis concentrates like hash rosin instead of butane hash oil.