People are being encouraged not to visit a disused quarry in West Tipperary which is often used as a popular location for swimming.
It follows the discovery of the remains of a dead horse in the water earlier today.
The site is known locally as the Blue Lagoon.
The limestone quarry has developed a distinct blue lake which is estimated to be up to 100 feet deep in places and is surrounded by rock with no sloped entry.
Concerns have been raised in the past about the safety of the site which regularly attracts teenagers – particularly during warm weather.