Health concern in using dehydrator to dry filaments  

I'm no expert in chemistry, but... Filament is dried (dehydrated =removing water) at relative low temperatures at which nothing else (from filament) would evaporate -at least so my opinion.
But still, you smell "something"... Try to run empty dehydrator for several hours in bathroom and check. I'm kinda sure you will notice same smell again. It probably comes from motor inside dehydrator. That's typical smell from new motor when we start using new aparatus and it should become much less noticeable over the time. But then, I hope there's no insulation melting on the wires inside.
Anyway, as always, there should be decent ventilation provided.

Tried to run it with nothing in already

Yes, when I bought it last year, the manufacturer asked me to run it empty as you suggested. After that, when I tried to dry the filament, there was a different smell but not as strong.

After not using it for almost a year, I took it out. I can't describe it in words but very very strange smell again just like when I got it the first time. I even put an air purifier under it and tried again. Still smelled very bad. I terminated the drying. 

Which filaments are you drying?

Cheerio,

Filament types and brands don't matter. It just smelled very bad. I will probably throw it away. 

The brands are unimportant but different types have different, more or less volatile components.  PLA shouldn't smell of anything except, perhaps, popcorn whilst ABS might be expected to be offensive.

Cheerio,

Dehydrator

I have a keen sense of smell and I dry filament all the time.  I do not smell anything from my dehydrator.  I also use it to dehydrate chemicals and do not get a smell.  You must b drying it at too high temperature or it is the dehydrator it self.  

Burning question

I was drying some PETG just the other day at my wife complained about the ‘burning smell’.  I was only running at 120F/50C, so I can’t think that was it.  I haven’t run it about a month- and I’ve gone longer than that and not gotten the smell.  I don’t know?  Maybe a moth or something else getting into the heating part????  It was only on the initial start up and went away on about 15 min.

I wonder if running the dryer for a few minutes before putting the filament in would preclude the dryer from trying to get to temp and overtemping the filament???

I still think it is something inadvertently in the dryer….

For certain

At that temp, it was something other than the PETG

Posted by: @milehigh3der

I was drying some PETG just the other day at my wife complained about the ‘burning smell’.  I was only running at 120F/50C, so I can’t think that was it.  I haven’t run it about a month- and I’ve gone longer than that and not gotten the smell.  I don’t know?  Maybe a moth or something else getting into the heating part????  It was only on the initial start up and went away on about 15 min.

I wonder if running the dryer for a few minutes before putting the filament in would preclude the dryer from trying to get to temp and overtemping the filament???

I still think it is something inadvertently in the dryer….

I know I've mentioned this before, but I dry filament in the air fryer set on dehydrate and it works quite well from what I can tell anyway. 

I just leave it open after doing filament and then use it for real food next evening. No smell or tell-tale aftertaste. 

Or unusually al-dente brightly coloured spaghetti?

GD&R

Cheerio,

Unfortunately, in this question I cannot help

Unfortunately, in this question I cannot help