Chemistry Lab Safety — Study Notes

Read these notes carefully before your first lab session. You will be expected to know and follow every rule here. Safe habits are part of your lab grade — and more importantly, they keep you and your classmates out of the nurse’s office.

1. Why Lab Safety Matters

A chemistry lab contains open flames, glassware, corrosive liquids, and reactions that release heat or gas. None of these are dangerous when handled correctly — chemists work with them every day. Accidents happen when people rush, skip steps, or assume “nothing will go wrong this time.” Safety rules exist because each one traces back to a real injury that happened to someone who didn’t follow it.

2. Before You Enter the Lab

• Read the procedure ahead of time. Know what you’ll be doing, which chemicals you’ll use, and what hazards are flagged in the pre-lab notes.
• Dress correctly. Closed-toe shoes, long pants or skirts covering the legs, and no loose sleeves or dangling jewelry. Tie back long hair completely — hair is flammable and catches fire faster than you can react.
• No food, drink, or gum — ever. Not even a water bottle. Chemical vapors and residues can contaminate anything open in the room.
• Know the room. Locate the fire extinguisher, fire blanket, eyewash station, safety shower, first-aid kit, and both exits before you need them.

3. Personal Protective Equipment (PPE)

• Goggles: Chemical splash goggles (not just safety glasses) go on before any chemical or glassware is out, and stay on until everything is cleaned up. Your eyes cannot be replaced.
• Apron or lab coat: Protects your skin and clothing from splashes and spills.
• Gloves: Wear them when the procedure calls for them. Remove them before touching your face, phone, doorknobs, or notebook — gloves protect you only if you treat them as contaminated.

4. Handling Chemicals

• Read the label twice before using any chemical. Many chemicals have similar names (e.g., sodium sulfate vs. sodium sulfite) but very different properties.
• Take only what you need. Never return unused chemicals to the stock bottle — this contaminates the entire supply. Dispose of extras as directed.
• Never taste or directly smell chemicals. To check an odor, waft: hold the container away from your face and gently fan the vapor toward your nose with your hand.
• Add acid to water, never water to acid. Diluting acid releases heat; pouring water into concentrated acid can make it boil and splatter. Remember: “Do what you oughta — add acid to water.”
• Point test tubes away from yourself and others when heating or mixing. Contents can spurt out unexpectedly (“bumping”).
• Keep containers closed when not in use, and keep flammable liquids far from any flame or hot plate.

5. GHS Hazard Symbols and SDS

Every chemical container carries GHS pictograms — standardized diamond-shaped symbols that warn of hazards at a glance. Know these six:

Every chemical also has a Safety Data Sheet (SDS) listing its hazards, safe handling, and first-aid measures. You can ask to see the SDS for anything we use.

6. Glassware and Heating

• Inspect glassware before use. Chipped or cracked glass goes in the broken-glass container, not the trash. Never handle broken glass with bare hands — use a dustpan and brush.
• Hot glass looks exactly like cold glass. Assume anything recently heated is hot; use tongs or wait.
• Never heat a closed container. Pressure builds up and it can burst.
• Bunsen burners: Light the match or striker before turning on the gas. Never leave a flame unattended, and turn off the gas completely when finished.

7. If Something Goes Wrong

Report every accident, spill, or injury to the teacher immediately — no matter how small. You will never be in trouble for reporting; you will be in trouble for hiding it.

• Chemical in the eye: Go straight to the eyewash station and flush for a full 15 minutes, holding the eyelids open, while someone alerts the teacher.
• Chemical on skin: Rinse the area with plenty of running water for 15 minutes. For large spills on clothing or body, use the safety shower.
• Fire on clothing or hair: Stop, drop, and roll, or use the fire blanket. Never run — running feeds the flames.
• Small bench fire: Step back and let the teacher handle it. Do not throw water on a chemical fire.
• Spill: Alert nearby students, then the teacher. Do not clean up a chemical spill yourself unless instructed.
• Cut or burn: Tell the teacher immediately, even if it seems minor.

8. Waste Disposal and Cleanup

• Nothing goes down the drain unless the teacher says so. Use the labeled waste containers for chemical waste, and the broken-glass box for glass.
• Clean your station completely: wipe the bench, wash and return glassware, cap all bottles, and turn off gas and water.
• Wash your hands with soap and water before leaving the lab, every single time — even if you wore gloves.

9. Conduct in the Lab

• No horseplay, pranks, or running. The lab is a workspace, not a hallway.
• Perform only the assigned experiment. Unauthorized “what happens if…” experiments are the leading cause of school lab accidents.
• Keep your workspace uncluttered — backpacks and coats stay in the designated area, never on the floor near benches.
• If you are unsure about any step, stop and ask. A question takes ten seconds; an accident can last a lifetime.

Quick Self-Check

1. Why must you add acid to water and not the reverse?
2. What is the correct way to check the smell of a chemical?
3. Where are the eyewash station and fire blanket in our lab?
4. Why should you never return unused chemical to the stock bottle?
5. What should you do first if a classmate’s sleeve catches fire?

Bottom line: Goggles on, read the label, no food, no shortcuts, report everything, ask when unsure.