A farmers' lobby group is urging people not to use sky lanterns to celebrate our health workers.
The warning from the Ulster Farmers' Union follows the launch of an initiative to encourage lantern releases in support of the NHS.
Sky lanterns, which are made of paper, have a flame at the bottom, like in a hot-air balloon, that makes them rise in the air.
But the UFU said they pose a major fire risk and are a hazard to animals.
UFU deputy president Victor Chestnutt said it was causing "serious concerns" for farmers and the rural community.
"We are asking members of the public who are planning to take part in this sky lantern spectacle to consider the consequences before using them," he said.
"The burnt-out remains from the lanterns often fall into farmers' fields, littering them and potentially hurting livestock.
"Not only are the sky lanterns damaging to the environment, there is the possibility that livestock could eat the metal wire frames which will then pierce their internal organs and cause them life-threatening injuries."
Mr Chestnutt also warned the lanterns could cause wildfires.
There has been a spate of gorse blazes across Northern Ireland in recent days.
Michael Robson, a pedigree Simmental cattle breeder from Co Antrim, previously lost a bull worth £20,000.
He said it would be better if people donated funds to the NHS.
The Robson family run Kilbride Farm at Doagh just outside Ballyclare and have been breeding pedigree Simmentals since 1971, making it one of the oldest Simmental herds in the UK and Ireland.
Mr Robson has urged people not to launch the sky lanterns in support of the NHS and to find another way to support the health workers.
"We do need to support our NHS and all the carers and essential workers during this dreadful pandemic, but not by launching lanterns," he added.
"The public needs to realise how dangerous they really can be and how costly they can be to a farmer with livestock and even crops.
"Perhaps people can donate to the NHS to show their gratitude for the efforts the health workers are going to keep us safe,"
The National Fire Chiefs Council said releasing lanterns in celebration of the NHS was "misguided" and warned of risks to livestock, agriculture, thatched properties and hazardous material sites.