Haumoana Beach (file image). Photo: RNZ / Tom Kitchin
The fatty, smelly substance found on a beach south of Napier that made two dogs sick was a waste byproduct from animal or food processing, and also contained hydrocarbon.
The substance was found on Haumoana Beach on 1 December.
A local said her dogs "went straight for it" and then started vomiting.
Hawke's Bay Regional Council sent samples away for analysis and the results had been returned, policy and regulation manager Katrina Brunton said.
"We are working with Hastings District Council to identify the source of the contamination.
"Since the initial incident and the days following there has been no further contamination wash up on the beach."
The area is safe to swim, she said.
Hastings District Council has been approached for comment.