If any furniture is placed, for instance, sofa or bed or something else very close to the baseboard heater, it will burn inside lightly for constant heat. At the beginning of this burning, it may not be noticeable, but it will show the outcome after a particular time. Meanwhile, You might be aware of furniture’s off-gassing.
Sometimes, the closest position of furniture to the heater is responsible for off-gassing. The polishing of furniture, which is most likely made from chemicals, releases toxic gases for being heated by the baseboard heater.