Defective heaters can cause serious personal injury to consumers and should not be used. If you are using a portable heater please make sure that it has been tested under the latest safety standards and that it is not the subject of a recall. Recently Walmart and Sears recalled the the Kenmore Oscillating Fan Heater because it was posing a risk of fire and burns to consumers. A broken motor mount can cause the units to overheat, catch fire and ignite nearby items.
Read more on the CPSC website