"If you want to play somewhere in the long summer evenings, please don’t choose a quarry."
That is the stark message from the Mineral Products Association to young people who might be tempted to cool off in a quarry.
The MPA has created a Facebook page Stay Safe Stay Out of Quarries to support the campaign and help spread the key safety messages to teenagers, parents and teachers.
"If you come in uninvited you will be exposing yourself to a whole range of risks," explains Elizabeth Clements from the MPA.
"With the hot spell, people have been killed in open water."
Already this summer two young men in Scotland and Norther Ireland have drowned in separate quarry incidents.
"It is just the typical thing of people being tempted to go swimming in this seemingly cool water, but as a lot of people know to their cost if you jump in it takes a long time to acclimatise.
"The water is incredibly deep and cold and you don’t know what lies underneath such as abandoned machinery.
"We try to get all those messages out, along with the fact that if you do get into difficulty your mobile phone is unlikely to work you might not be found for some time."
Fatalities in recent years show that it is younger people and teenagers in particular, who are most at risk of drowning in deep and cold water, falling down sheer faces and being buried in sand stockpiles or quicksands.
"We are dealing with teenagers, so we use Facebook and we have posted a new video on YouTube where we use the testimony of friends and family of teenagers who have been killed in the past few years," says Ms Clements.
"It is very poignant. We are just trying to strike a chord with young people."
An MPA survey shows that more than 58 per cent of site managers who responded experienced trespass over the past year. However, it is not just would-be swimmers who trespass in quarries and other sites.
Two thirds of managers able to determine a motivation said it was to break in and steal.
Ms Clements says there is a rise in theft and vandalism, including sites being targeted for metal theft.
"People are going in and endangering themselves by stealing as well as putting other people at risk. They are breaking down fences and making it easier for other people to get in."
Another menace are so-called "urban explorers", thrill-seekers who break into sites to perform feats such as climbing high chimneys and then taking photos that they then show off online.
"They are not necessarily doing any damage but they are putting it up on Facebook and broadcasting to others including children that sites are for recreational activities rather than industrial use."
Ms Clements says that while this year’s death have not taken place on operational sites of the 430 MPA members, many of them small operators, "we feel responsible as a trade association".
MPA represents "a fair percentage" of the estimated 1,300 quarries in the country and is working with other groups, such as the Country Landowner’s Association and the NFU, whose members own quarries or have them on their land.
"It is important that the messages get across - you should not go into any sort of quarry."