Quarry operators and emergency service chiefs have joined forces to urge people to stay out of quarry lakes.
The plea comes almost a year after two people drowned at Bawsey Pits, a former quarry near Lynn, and amid fears warm summer weather could tempt swimmers to danger areas.
The call from the Mineral Products Association, the body which represents quarry operators, has been supported by both the Norfolk Fire Service and safety campaigners.
Roy Harold, the county’s deputy chief fire officer, said: “The emergency services are regularly called to assist in the rescue of members of the public who have got into difficulty, often in quarries.
“Failure to appreciate the low water temperatures that exist in quarries, lakes and rivers even in summer causes difficulties for people and all too often results in the worst possible outcome.
“The message to the public is simple – never ignore the warning signs at quarries and industrial sites. These sites are not adventure venues but present real danger of serious injury and death as experience has shown on too many occasions.”
Ryan Pettengell, who was 41 and from Lynn, and 16-year-old Umar Balogun died after getting into difficulty in the Bawsey Pits lakes in July last year.
The Royal Society for the Prevention of Accidents (RoSPA) says around 400 people drown in the UK each year.
David Walker, RoSPA’s leisure safety manager, said many of those deaths were caused by misjudgements like underestimating the effect of swimming in cold open waters such as those found in quarry lakes.
He said: “People should be able to enjoy adventurous activities but it is important that they understand the risks they are taking and take appropriate actions to mitigate them.”