Dozens of people suffer from Norovirus-like symptoms after attending the big Lego event in Bristol last weekend.
The organizer of the Bristol Brick event said they were 'destroyed' and an investigation has been launched by the city health authority.
Nearly 4,000 people visited the Indoor Action Sports center to celebrate Lego but after the event, more than 40 participants began experiencing illness and diarrhea.
A Lego fan, who wants to remain anonymous, said he was not happy with the cleanliness of the place.
He said: "The state of the place left a lot to be desired."
"The food is not good and during the weekends, the toilet is not well maintained, the sink doesn't work well and there are no hand sanitizers and things like that."
"At least 40 people I know have been affected."
The Bristol Brick Show published a post on its Facebook page on Wednesday afternoon, which said: "Thank you all for coming to our show, enjoying it and helping us raise money for two very valuable charities.
"We have been made aware that a number of people who attended our events over the weekend have been exposed to the virus.
"Unfortunately there were no disease reports made during the show, so we have no way to warn anyone or identify the source at the time.
"Many of you will know that Bristol has recently seen several cases of Norovirus affecting schools, hospitals and other businesses in the area and the combination of that plus nearly 4,000 people through our doors over the weekend seems to have contributed to the outbreak.
"We held the same event at the same place last year with no known problems so we believe this is an unfortunate and isolated incident.
"As organizers, we are very sad that this has put a damper on the event that was declared a success, we hope everyone affected by the recovery is fast.
"Thank you for your continued support and we hope that your memories of this performance will not be tainted by these events!"