BEACHES have re-opened after a massive clean-up of a bright yellow foam that caused a chemical alert.
Experts believe the oil-based substance that washed up on beaches at Hayling Island and the Witterings came from a vessel at sea.
The Maritime & Coastguard Agency has launched an investigation to find out where the substance came from.
Beaches on Hayling remained closed to the public yesterday as 12 staff from Havant Borough Council bagged up the oily material.
Initial tests from Hampshire Fire & Rescue have shown the substance is castor oil and not a threat to human or animal health unless it is ingested.
A more detailed examination is taking place by the Environment Agency.
There is also a chance the material is palm oil, a substance found in soap.
Chichester District Council re-opened its beach and Havant Borough Council re-opened most of Hayling beach.
Stuart Pinkney, safety and emergency operations officer for Havant Borough Council, said: 'The stretch of beach from the Fun Fair going east to Sandy Point is now clean and open.
'The final stretch from the Fun Fair going west to the Ferry is still being cleaned. However, I am confident that we will finish the clean-up operation by close of business today.
'I have re-visited areas which were cleaned yesterday but due to the windy conditions blowing debris across the beach from other areas it has needed to be cleaned again.
'The substance is very sticky and messy if you get it on your shoes.'
Experts say the substance washed up at high tide at about 10pm on Monday.
The material will be put in steel containers while the council decides how to dispose of it, either through incineration or landfill.
Mr Pinkney added: 'We don't know whether it's been discharged legally or illegally. That will be subject to further investigation.
'It could be anywhere in the Atlantic.
'Whether it was accidental or deliberate, we don't know.'