HSE teams joined police and rescue services at command centres and have advised on matters including the presence of asbestos and LPG tanks at Wood Flour Mills, in Bosley, near Macclesfield.
A body has been found by the rescue team searching for four people who have been missing since an explosion and fire at a mill. Police said the body had not yet been identified.
In a statement, the Executive said: "HSE, and specialists from its Health and Safety Laboratory (HSL), will join the other agencies in seeking to establish the cause of the incident.
"The thoughts of everyone at HSE are with those affected by this incident."
For updates, follow @CheshireFire, @cheshirepolice and #BosleyIncident