Tattoo guns, knives and nunchaku have been stolen from a tattoo parlour in Holderness Road, east Hull.
An outbuilding at Prince John's, at the corner of Bellfield Avenue, was raided this week.
Now, police are concerned the specialist equipment may fall into the wrong hands.
If used by people without proper training, tattooing equipment can cause scarring and infections.
Hull City Council's health and Safety team said people should only consider using businesses registered with the council.
It advises: "All procedures should be performed with new, clean pre-packed needles.
"Never accept a needle that has been taken out of liquid – it will not be sterile and could lead to infection.
"The most important thing is for people to trust their instincts. If they enter a premise and don't like what they hear or see, they should leave and find someone they trust."
The stolen items include:• A red 'Neo tatt tatt' tattoo gun – valued at £280• A blue 'Neo tatt tatt' tattoo gun – valued at £280• A gold 'Ronnie Star' tattoo gun – valued at £140• Several generic twin-coil tattoo guns• Ornamental knives• Nunchaku with dragon engraving• Inks with brand name Eternal
Anyone with information about the burglary, between 7.30pm on Tuesday and 8am on Wednesday, is asked to call 101, quoting crime reference 1982450, or speak to Crimestoppers anonymously on 0800 555 111.
