You should have guidelines and procedures for each of the following:

1. First Aid Stations
2. Reporting accidents
3. Emergency response guidelines
4. Personal safety
5. Where to get Material Safety Data Sheets
6. Special disposal of chemical wastes and sharp objects
7. Small chemical spills
8. Food and beverages in lab
9. Contact lenses and eye protection
10. Laboratory coats, clothing, and shoes
11. Doors propped or wedged open
12. Microscopes
13. Laboratory equipment (a procedure for each piece of equipment)
14. Open flames or other heat sources
15. Chemical safety issues
16. Live organisms

In general, you should also commit to the following rules:

1. Encourage all students and teachers to care about their health and safety.
2. Do not allow students to conduct unauthorized experiments or "play" with equipment.
3. Make learning how to be safe an integral part of science education.
4. Require every pre-lab session to include safety considerations.
5. Forbid students to work alone or unattended.
6. Develop plans and conduct drills for dealing with emergencies.
7. Maintain a chemical inventory and use warning signs and labels.
8. Require good safety practices in all work areas.
9. Use appropriate personal protection at all times.
10. Keep current on safety issues in your classroom and school.

Some useful sources:

http://www.labsafety.org