Ammonium nitrate: Fear around the world as nations consider their own huge stashes of chemical responsible for Beirut explosion

The devastating explosion of 2,750 tonnes of ammonium nitrate in Beirut has raised fears about similar stockpiles of the fertiliser in other nations.

In the wake of the blast that killed more than 150 in Lebanon's capital, authorities in the southern Indian city of Chennai say they have seized 740 tonnes of the highly explosive chemical.

Customs officials said the consignment had arrived in the port city in 2015, purchased by a chemicals firm from another state in India, but was impounded because of an alleged breach of import rules and stored at a facility some 20km outside the city.

Officials said that while there are no residential neighbourhoods within 2km of the freight station where the ammonium nitrate was being stored, it had been decided after the Beirut incident to move it to a safer location.

“The seized cargo is securely stored and safety of the cargo and public is ensured considering the hazardous nature of the cargo,” customs officials said in a statement late on Thursday.

Other stockpiles of the chemical, which is commonly used both as a fertiliser and in mining operations, have raised concerns in Australia.

One plant which can store as much as 12,000 tonnes of ammonium nitrate is located just 3km from the central district of the New South Wales town of Newcastle.

Orica, the company which owns the facility, said that there had never been any incidents in the plant’s 51-year history and insisted safety measures including fire-resistant storage and tight government regulations meant there was no risk.

But some were still not reassured, including chemical engineer Keith Craig, a member of a local community volunteer group. He told Australian media a blast at the Orica facility would “flatten Newcastle”.

“We’ve seen what happened in Beirut and it’s time to move on. That tiny window of risk could be a catastrophic outcome,” he told the AAP news agency.

“You just don’t have that sort of plant in the community. The risk is just not worth it.”

A separate fertiliser plant just 500m from the inner harbour of Port Adelaide, in South Australia, raised concerns as long ago as 2013. Locals and the state government eventually persuaded the company which owned the plant to move it elsewhere and today the firm, Incitec Pivot, said their relocated plant did not store ammonium nitrate for the mining industry, but only fertiliser for farmers.

Ever since the IRA used the chemical to produce bombs in the 1970s, ammonium nitrate has been strictly controlled in the UK too. Experts say there is a very low risk of any similar disasters occurring in Britain.

Hundreds of sites are recorded by the Health and Safety Executive (HSE) as storing more than 1,250 tonnes of the substance, but guidance lays out how to store not more than 300 tonnes in a single stack in well-ventilated areas away from flammable materials.

Most ammonium nitrate in Britain also has less than 28 per cent nitrogen, which renders it much less dangerous.

A spokesperson for the HSE said: “’The storage of ammonium nitrate in Great Britain is subject to a robust regulatory framework, which considers the hazards posed by storage, product safety and measures to deal with emergencies.

“As with all industrial disasters around the world, we will take on board any significant findings from the investigation as and when they emerge.”