Which safety feature is crucial for smoke detectors in residential areas?

The crucial safety feature for smoke detectors in residential areas is the hazardous material warning label. This feature is important because it alerts occupants to the presence of potentially dangerous substances that could be released during a fire, ensuring they understand the risks they may encounter. In emergencies, clear communication of hazards is vital for safety.

Options like battery life indicators, maintenance reminders, and Wi-Fi connectivity serve useful functions but do not directly relate to the immediate safety concerns of smoke detectors in the event of a fire. A battery life indicator helps ensure the smoke detector is functional, while a maintenance reminder assists homeowners in keeping the device in good working order. Wi-Fi connectivity can enable notifications or monitoring, but it does not enhance the direct safety of the device like a hazardous material warning label does.