Shorted out after 6 months of use

We have had this humidifier for maybe 6 months due to various illnesses in our family. We use it nightly in our children's bedroom. Once a week we clean the mineral build-up from the boiler piece per the manufacturer's manual.
This morning we woke up to a burning plastic/chemical smell. Like if your wires were burning. Well, we unplugged everything in the room, not knowing where it came from. The first thing we checked though was this unit. Something was burning up, and my husband said that the part where the smell was coming from was hotter than usual. So, something went wrong, but the unit did not shut down.
So 1)If this had started much earlier in the night, I fear a fire may have erupted at the foot of my child's bed.
2) I'm not sure how long this chemical stench is going to take to dissipate from our home. We have 4 people recovering from bronchitis, (one of whom has asthma) and a 5 month old whom I don't want breathing in these chemical smells (smell of burning plastic has not gone away after airing the house out in 25' weather for a full day with ceiling fans on high).
It's very scary to wake up to a smell like that and try to determine if you can stop the slow burn before it starts a fire or not. Something should be done, but I'm not sure what. I can tell you that I will NOT be buying another Honeywell product!