Oil spilled into a quay in Emsworth after a drilling platform collapsed, according to the authority that manages the site.
Chichester Harbour Conservancy’s Patrol Team said it responded to reports of an oil spill as a result of the incident involving a crane at Dolphin Quay on Tuesday (July 30).
A spokesperson said: "The patrol team deployed oil spill equipment at the site to contain the spill of hydraulic fluid and engine oil.
"They were later supported by the on-call specialist response team from Adler and Allen who deployed additional booming.
The patrol team’s initial booming was successful at containing the spill and actions to recover the oil are underway. Monitoring of the site will continue over the next 48 hours."
The drilling platform, owned by Farlington firm Burras Ltd, was being used to build foundations for a new development project on the quay.