Lothian and Borders Police has co-ordinated the multi-agency response to the leak of effluent from a pipe which runs from Dalmeny Tank Farm to Hounds Point in South Queensferry, near Edinburgh.
The oil company, BP, which runs Dalmeny Tank Farm, is working to resolve the leak and as a precautionary measure a 100 m exclusion zone has been put in place on either side of where the leak is entering the Firth of Forth.
NHS Lothian has advised that the gas associated with the effluent does not present any risk to the public.
A spokesman for NHS Lothian said:
Although this gas has a strong smell, it will have no impact on the health of local residents due to the low levels released.
"However if anyone has a health concern they should contact their GP."
Lothian and Borders Fire and Rescue Service and SEPA has been monitoring the effluent and SEPA is providing expert advice on any possible implications of the leak.
Again as a precaution, cordons were put in place in Standing Stanes, Dalmeny and at the west end of the High Street in South Queensferry.
A spokesman for Lothian and Borders Police said:
The leak was reported by a member of the public who spotted discoloured water trickling into the Firth of Forth. An investigation pinpointed the source of the problem and a multi-agency response was put in place to respond."