After traces of formalin were found in fish brought from Bangladesh, the Tripura government has stopped fish import from the neighbouring country through its seven Land Customs Stations (LCSs), except for the Agartala-Akhaura ICP, a minister said here on Friday.

Health and Revenue Minister Badal Choudhury said the preservative -- formalin or formaldihyde, mixed with water and used for preservation of biological specimens -- was found in six samples drawn from fish imported from Bangladesh. The chemical is dangerous for human consumption.

"Health officials have been asked to take stringent legal action against those using formalin and other illegal preservatives," Choudhury told IANS.

"The government has asked customs and other authorities to prevent the import of fish from Bangladesh through the seven LCSs, except the Agartala-Akhaura Integrated Check Post (ICP)," he added.

The seven LCSs are in Agartala, Srimantapur, Khowaighat (western Tripura), Kamalpur, Old Raghnabazar (northern Tripura), Belonia and Sabroom (in southern Tripura).

Agartala-Akhaura ICP is the second-largest trading point along the India-Bangladesh border after Petrapole-Benapole land border in West Bengal.

"Since no adequate infrastructure and manpower is available at the seven LCSs, import of fish through these border points would be risky," he said.

Choudhary said that following media reports, Health Department officials collected 40 fish samples from Agartala, and formalin was found in 11.

"Of these 11 samples, five were collected from two main fish markets of Agartala and six from fish imported from Bangladesh," Choudhury said.

Formalin, a poisonous and anti-decomposition chemical agent, is used as an antiseptic, disinfectant and preservative in various items.

The minister said food safety officers are collecting samples randomly from markets and getting them tested at laboratories.

Under the Food Safety Security Act and Rules, 2011, anyone found guilty faces a penalty of Rs 1 lakh to Rs 10 lakh, or imprisonment, or both.

An official of the Industries and Commerce Department said that, on average, 25,644 kg of fish are imported daily from Bangladesh and 26,180 kg bought from outside the state, including from Andhra Pradesh.

"These fish imported from Bangladesh and brought from other states are being sold in Tripura markets without any lab tests," the official told IANS on condition of anonymity.

Tripura is surrounded by Bangladesh on three sides, making up for 85 per cent of the state's 856-km international border.

However, there are no LCSs or border fencing in many areas on the India-Bangladesh border along the northeastern states of Tripura, Meghalaya (443 km), Mizoram (318 km) and Assam (263 km) due to which informal trade and smuggling flourishes.

"Informal trade leads to supply of imported fish which are a health hazard," said Dr Chandan Sarkar, working at the government-run G.B. Panth Hospital.