Which of the following is a common fire hazard?

Unattended heaters represent a significant fire hazard due to their potential to overheat and ignite nearby materials if left unmonitored. Heaters can generate a lot of heat; if they are placed close to flammable objects like furniture, clothing, or paper, the risk of starting a fire increases dramatically. Additionally, if someone accidentally knocks the heater over or if it malfunctions, it can pose an immediate danger.

The presence of loose boards or carpets, while they may lead to trips and falls, does not inherently increase the risk of fire the same way unattended heaters do. Similarly, loose handrails can create safety hazards related to falls but are not a direct fire risk. Oily or wet floors might contribute to slips and falls but do not present the same level of fire danger that unattended heating devices do, which can result in quickly advancing fires in a space.