經營米德爾斯堡附近場地的PD Ports公司說，該發現是在北京時間17:30左右在Tees Dock集裝箱碼頭發現的。
消防部門說，"一名危險材料顧問 "正在現場 "處理潛在的化學品泄漏"。
Teesport near Middlesbrough, pictured in 2021, is the fifth largest port in the UK
Emergency teams are at the scene of a suspected chemical leak from a liquid bulk tank at Teesport.
PD Ports, which operates the site near Middlesbrough, said the discovery was made at around 17:30 BST at a Tees Dock container terminal.
The port has been closed to traffic and Cleveland Fire Brigade has advised people to avoid the area.
The fire service said "a hazardous materials advisor" was on site "dealing with a potential chemical leak".
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Three engines from Grangetown and Thornaby are in attendance.
Cleveland Police and the North East Ambulance Service have also been called to the scene.
"We are working closely with the local emergency services to investigate the incident," PD Ports added.
"We will continue to update as necessary and thank you for your patience."
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