Balls that washed ashore and closed string of famous beaches contained scores of different materials ‘consistent with contamination from sewage’

Thousands of mystery balls that washed up on Sydney beaches last month were gunk globules made of products such as motor oil, hair, food waste, animal matter and wastewater bacteria – but their source is yet to be traced.

A statement from the NSW Environment Protection Authority on Wednesday confirmed the balls comprised fatty acids, petroleum hydrocarbons and other organic and inorganic materials – and were not tar balls as previously theorised.