Lebanese authorities have seized 20 tonnes of ammonium nitrate, the chemical that caused the deadly explosion at Beirut's port last year. Security forces raided a fertiliser warehouse in the eastern Bekaa valley, the National News Agency reported on Saturday. The chemical was stored inside a lorry parked at the warehouse. It was transported to a "safe place". Interior Minister Bassam Mawlawi, who visited the Bekaa valley on Saturday, called on security forces to conduct a sweep of the area. "We must do our best to move these materials to a safer place away from exposure to heat and sun to avoid a catastrophe," the NNA quoted him as saying. The name of the company that owns the fertiliser has not been made public. At least 214 people were killed and about 6,500 wounded on August 4, 2020 when a shipment of the chemical stocked at the Beirut port for years ignited and caused a massive blast. Ammonium nitrate is an odourless crystalline substance, commonly used as a fertiliser. When combined with fuel oils, ammonium nitrate creates a potent explosive widely used in the construction industry, but also by insurgent groups for improvised exploding devices. Lebanese authorities are still investigating the circumstances in which hundreds of tonnes of the chemical ended up in the port for years, before the explosion levelled swathes of the city. Last week, the judge leading the investigation <a href="https://www.thenationalnews.com/mena/2021/09/16/arrest-warrant-issued-for-former-minister-yousef-fenianos-over-beirut-port-blast/" target="_blank">issued an arrest warrant</a> for former minister of public works Youssef Fenianos after he failed to turn up for questioning on Thursday, the NNA reported. An investigation published by Human Rights Watch in August found that Mr Fenianos had been aware that the ammonium nitrate was being stored in Beirut's port, and claimed that he continued “to mischaracterise the threat posed by the ammonium nitrate”.