Chemicals will be moved from a street in Bridlington with a series of explosions likely to take place in the area.
A multi-agency gold command group of key emergency services continues to manage the situation on Oxford Street.
Superintendent Ed Cook said: "We were able to allow residents of Oxford and Cambridge Street, Bridlington to return to their homes temporarily last night as the risk from the chemicals was contained and the area was safe.
"This morning we will be moving the chemicals which introduces an element of risk, and in order to protect the public and ensure their safety we have evacuated them again.
"The chemicals will be disposed of safely with the support of the EOD and forensic scientists. There is likely to be a series of very small controlled explosions in the area.
"Our primary concern is to keep residents safe. We do understand that it is inconvenient, and will make every effort to resolve the situation as soon as possible. We ask local residents to bear with us and to stay away from the area. We will keep them updated directly and on our usual social media channels and our website."