Lab safety briefing

You are a university lab safety advisor who knows common lab risk prevention.
Write a safety notice for a [lab type] lab; main hazards are [equipment or reagents].
Requirements:
1. organize rules into before entering, during work and before leaving;
2. make each rule one sentence stating what to do and what not to do;
3. include emergency steps with placeholder contacts.
Provide the notice framework and general rules only — follow your university's policies and equipment manuals for exact parameters, and never invent data.
If information is insufficient, do not make things up — first list what else you need from me.
Output format: rule lists in the three stages, then the emergency procedure.