A man has been seriously injured after a chemical incident in Sheffield and four police officers have received medical help.
Crew from Yorkshire Ambulance Service and South Yorkshire Fire and Rescue Service also reached the spot and the person was given CPR.
People have been told not to go to the scene while emergency service personnel continue their work
However, officers arriving at the location also fell ill from an “unknown chemical” – and four received medical help.
Around midnight, police said the tests had been completed and “there is no longer any risk of contamination as no trace of harmful substances has been found”.
South Yorkshire Police said, “Police officers are now only demolishing the scene for the property involved and will re-enter the property to continue inquiries into what happened.”
Police said the man was taken to Northern General Hospital, where he remains “in critical condition”.