Police have launched an investigation after 33 people suffered suspected carbon monoxide poisoning at a go-karting track.
A spokesperson said: "We are working with other agencies to see if this is linked to the venue."
Among those affected was Adam Colbourne, who was at the track with his eight-year-old son, Henry. They spent the night in hospital after falling ill.
Mr Colbourne said his son initially went outside to get some fresh air after feeling unwell.
He added: "Next thing I knew, he came back up, said he felt dizzy. He was absolutely white as a ghost. There was nothing there. I tried to stand him up and he just collapsed onto the floor in a heap.
"Henry was on the children's ward because his carbon monoxide levels were about 14% and they should only be about 1%, so they kept him on oxygen throughout the night.
"Carbon monoxide is a killer isn't it? This could have been one of the most serious things that happened."
Police have contacted other people who were at the track to inform them about the issue.
Lincolnshire Integrated Care Board said it believed 33 people "may have suffered with suspected carbon monoxide poisoning".
Clair Raybould, director of system delivery, said: "We are working together across the health and care system to ensure we are able to support the small number affected quickly and safely following reports of people feeling unwell following their visit to the karting centre.
"We would ask anyone experiencing symptoms linked to this to seek medical advice via NHS111. We would also like to reassure the public that, unless they have been to the centre on 15 August specifically and are also experiencing symptoms, they do not need to act."
Symptoms of carbon monoxide poisoning include headaches, dizziness and nausea.
Gridline has yet to respond to requests for a comment.
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