TWO workmen caused a full-scale emergency alert at police headquarters when they turned up with a box containing a mysterious white powder.

The workers thought they had stumbled across a parcel of drugs and wanted to hand it over to police. But officers were forced to call out the fire brigade and chemical analysis experts after fearing the box might have contained highly toxic anthrax.

After a three-hour wait experts finally identified the substance as baking soda, but Hatfield firefighter and sub-officer Steve Duncan said the incident was treated as a serious alert A decontamination shower and shelter had to be set up to secure the area and all those who came into contact with the powder were forced to remove their clothes and wait in a holding area for a period of time.

Sub-officer Duncan added: “You never know what it could possibly be and we can not afford to take a risk. We have to think of the worst case scenario and protect the people as much as possible.

“Luckily on this occasion it wasn’t anything serious, but we had everything in place to cover for all eventualities.” The two workmen turned up at police headquarters in Stanborough Road, Welwyn Garden City, at around noon on Monday with the box in the back of their van.

They came across it while carrying out road repair work close to the A1M motorway.

Although the package was never removed from the back of the van, officers decided to call out the fire brigade to help investigate.

Mr Duncan added: “We were there for around three hours. Most of that time was spent waiting for confirmation from the experts that the substance was not harmful.” A police spokesman said: “We were alerted to a suspicious package which had been brought in to police headquarters. The driver had recovered the package from a grass verge next to the water pumping station at Junction 3 of the A1M.

“The incident was dealt with as a potential hazardous substance and a number of other agencies were involved.

“Close examination of the package revealed the contents not to be harmful.”