EHS need concern a lot of issues, which include but not limited to

1, Utilities status impact (cool down or just warm down), especially for the key points (system on line or off line)

2, Risk Assessment for the shutdown (high risk work evaluation, miss operation possibilities)

3, Safety trainings & critical remind (For your company & involved vendor or sub-contractor)

4, Emergency response plan, if incident occurred what you mentioned before (Remind to have a contact window to all relevant department)