or impending spillage, release or escape of a chemical, radiological or other
substance that is capable of causing loss of life, injury to a person or damage
to the health of a person, property or the environment.
Space debris has been descending out of orbit at an average rate of about one object per day for the past 50 years . In 1979 debris from Skylab landed south-east of Perth and was found between Esperance and Rawlinna.
 Johnson, Nicholas (5 December 2011). "Space debris issues". audio file, @0:05:50-0:07:40. The Space Show. Retrieved 8 December 2011.