I have been using Stealth heaters for the past few years w/o problems, until just recently when 1 quit working (stopped heating all together). When I inspected it, a 2 inch section in the plastic had split open and I could see the inside slightly. Did not appear to be a melting of the plastic, just looked like the plastic shell cracked open like it was brittle or something. I called customer service & even though I don't have my original receipt, since it carries a lifetime warranty they said I could mail it in for repair/replacement (they did warn me that w/o receipt they would only honor the warranty 1 time, which seems fair enough).
Very glad there was no electricution or meltdown, etc. And, very happy with the response I got from customer service. Hopefully I'll get my replacement back soon...