A security expert was warned site managers to review anti-theft precautions on plant and equipment left outside.
Andrew Hallam, managing director of Premier Security Services, says a spate of thefts of salt from gritting depots throws a spotlight on the vulnerability of goods and materials that are not kept under lock and key.
One gritting company in Wiltshire was forced to bring in security guards after six of its depots were targeted by thieves in January.
But is not just salt and aggregate that are at risk. Plant hire companies, haulage firms and warehouses with outside storage areas are all easy picking for thieves unless they are well secured.
Mr Hallam warned: "Unlike buildings that are locked up and alarmed, outside storage areas are often only protected by an ordinary wire gate and simple padlock that are easy to break for determined thieves.
"Unless you have sophisticated external perimeter protection, you are giving a green light to petty pilferers and organised criminals. By the time the police or key holder has arrived, you may have lost tens of thousands of pounds."
Perform a thorough inspection of your perimeter fencing and gates
Install a detection system that covers outdoor space
Hire an alarm response service (Premier provides a key holding system so that trained, uniformed guards respond immediately to alarm calls.)
Consider hiring a patrol service (Patrol guards perform visits to your premises during the night, a cost-effective alternative to full-time guarding)
Invest in high security padlocks and gates
Tag and mark all plant and equipment with serial numbers