A Cleveland Police officer is 'glowing' with pride at the work being carried out by the crime prevention team.
Yellow peril for Cleveland Police Sgt Glynn Bass
Sgt Glynn Bass uses "smart water", which shows up in ultra-violet light, to catch criminals in Middlesbrough.
But a faulty trigger system on a car used in covert operations has left his face, hands and clothes sprayed fluorescent yellow.
The effects stay on the skin for weeks, but Mr Bass said it proves the effectiveness of the product.
Captured on video
Mr Bass said: "It was a small problem with some wiring for a smart water trigger.
"We use smart water in decoy vehicles and switched the system on, the wiring fault meant I got a face full of it.
"We are using it in vehicles we know criminals will break into, and park them in areas suffering high crime levels and it gives us a chance to identify the thief."
The incident, which was captured on a police video, happened three weeks ago, but Mr Bass' skin still shows traces of the smart water.
He added: "The water shows up under UV light, so it is good my nightclubbing days are over."