Tonnes of vegetables exported from Calcutta have been sent back by European and Gulf countries as they reached the destinations stale, a consequence of an X-ray scanner at the airport lying defunct for 11 days.

Sources said the lone X-ray scanner in the airport's perishable cargo handling area malfunctioned from September 24 to October 4, forcing exporters to keep the vegetables in the non-perishable cargo section for a few hours till they were loaded on flights.

"Since the vegetables were stored in the non-perishable cargo section, which lacks an air-conditioning storage, most of them became stale when they reached their destinations," an exporter said.

"Around 60 per cent of the 100-odd tonnes of vegetables exported through Calcutta airport to Europe and the Gulf during the 11-day window before Puja had been sent back. The rejected cargo - which included gourds, long beans, papayas, fresh turmeric, ridge gourds and flat beans - is worth around Rs 80 lakh."

The scanner, which officials said malfunctioned several times over the past few years, was finally repaired just before Durga Puja.

Vegetables to be exported are packed in cardboard boxes and brought to the airport in refrigerated vehicles. They are off-loaded at the airport's cargo complex and taken to the centre for perishable cargo, which houses an air-conditioned storage facility.

The items are kept in the store till they are loaded on flights to ensure they retain their freshness.

The boxes, however, have to pass through an X-ray scanner before they are allowed into the store.

During the period the lone X-ray scanner in the perishable cargo section did not function - September 24 to October 4 - the vegetables had to be taken to the non-perishable unit where there is no AC storage facility.

"You cannot take an item to the perishable cargo section after getting it scanned in the non-perishable cargo section," said Ankush Saha, an exporter. "So, the vegetables had to be kept in the open in the non-perishable cargo unit overnight."

Saha alleged importers at the Heathrow airport in London had rejected 15 tonnes of vegetables he had sent before Puja.

Mrinal Sinha, the secretary of the West Bengal Fruits and Vegetables Exporters' Association, said: "We have been requesting the airport authorities to replace the old machine which malfunctions often but they have not done so yet."

Officials of international airlines said often consignments booked for a flight during the September 24-October 4 window had to be flown out the next day because of the delay related to the X-ray scan.

The airport authorities said two new X-ray machines would be installed by the end of November in the perishable cargo unit. "One of the new scanners will be on stand-by. So this problem won't recur," an airport official said.

The state exports around 2,500 tonnes of vegetables annually, 30 per cent of which go to Europe.