Final answer:
The statement is false because hazardous materials like carbon monoxide are odorless and tasteless, making them undetectable by smell.
Step-by-step explanation:
The presence of hazardous materials cannot always be detected by the sense of smell. For example, carbon monoxide is odorless and tasteless, which makes it particularly dangerous because it cannot be detected early through smell. On the contrary, substances like ammonia and household natural gas are added with a distinct smell to alert of their presence, despite them being hazardous as well. Therefore, relying solely on one's sense of smell to detect hazards can be misleading and unsafe.