Which household appliance is NOT commonly associated with fire hazards?

The correct choice is the oxygen concentrator, as it is not typically associated with fire hazards compared to the other appliances listed. Oxygen concentrators are designed to provide a continuous supply of oxygen to individuals who need it for medical purposes. While improper use or malfunction of any electrical device can pose some level of risk, oxygen concentrators themselves do not generate heat or have exposed heating elements, which are common fire hazards in other household appliances.

In contrast, microwaves, ovens, and hair dryers can all create fire risks under certain conditions. Microwaves may ignite food items that are overheated or improperly placed inside. Ovens can pose dangers if flammable materials are nearby or if there’s a failure or malfunction leading to overheating. Hair dryers can also present risks if left unattended or if they overheat due to lint buildup or electrical failure. Thus, when evaluating which appliance is not typically associated with fire hazards, the oxygen concentrator stands out as the safest option.