A number of bangs were heard across Derby shortly before 14:00 BST and large, black plumes of smoke were visible for miles, the BBC reports.
Main line train services have been suspended and residents are being advised to stay indoors.
https://twitter.com/PMBreakingNews/status/1120322550582644736
i’m at the scene of a huge explosion in derby city centre. four large booms shook the city. thick black smoke is billowing towards the sky pic.twitter.com/EW0J2ZJAJD
— Paige Oldfield (@journo_paige) April 22, 2019
https://twitter.com/tomemery9/status/1120316034391654402