If an expression is "hazardous," what does it imply about safety?

When an expression is described as "hazardous," it indicates that there is a significant risk involved that could potentially lead to danger or harm. The term is often associated with situations, materials, or activities that pose a threat to health, safety, or environment. In safety contexts, identifying something as hazardous usually means that precautions need to be taken to mitigate the risk or to protect individuals from potential harm. This understanding is crucial in various fields, such as environmental safety, occupational health, and emergency response, where recognizing and managing hazards is essential for maintaining safety standards.

The other options do not convey the same level of risk. "Safe" implies there are no dangers present, while "routine" and "common" suggest regularity and familiarity without any indication of danger. Thus, these terms do not align with the implications of being hazardous.