Over the past ten years there have been multiple incidents of hotplates spontaneously heating in the OFF position leading to fires and explosions. Lawrence Berkley National Laboratory, the University of California, University of Pennsylvania, MIT, Oak Ridge National Lab, and Northwestern University have issued safety warnings due to incidents on their campuses related to hotplate malfunction. Hotplates purchased prior to 1984 do not have temperature feedback controls. In particular, the models Corning PC-35 and PC-351 and the Thermolyne Model SP46925 are inherently unsafe by their design. Such older models can spontaneously heat with the heater dial in the OFF position. Other hotplates with reported malfunctions include Corning models PC-200, PC-220 and PC 420 as well as Fisher Isotemp.This is the first I've heard of it, although I'm not especially surprised. (Here's a poster from Northwestern and a comment from Oak Ridge National Labs.)
Anyone else hear about this? I presume that IKA stirplates don't have this issue, but I dunno.
UPDATE: Nope, Anon1226p in the comments has a picture of an IKA stirplate burnt up because of this issue as well.