Complex sentence: An environmental hazard is a substance, state or event which has the potential to threaten the surrounding natural environment and/or adversely affect people's health, including pollution and natural disasters such as storms and earthquakes.
Split into simpler sentences: An environmental hazard is a substance, state or event which has the potential to threaten the surrounding natural environment and/or adversely affect people's health. This term incorporates topics like pollution and natural disasters such as storms and earthquakes.