At the end of a lab session, you need to clean your workspace, dispose of waste properly, store chemicals and equipment, remove protective gear in the right order, and wash your hands before leaving. Skipping any of these steps can create hazards for the next person using the space or put you at risk of carrying contaminants out of the lab. Here’s what a thorough end-of-lab routine looks like, step by step.
Clean and Decontaminate Your Workspace
Start by wiping down your bench or countertop. For general chemistry labs, a 60%–90% ethanol solution is the standard for surface decontamination, as its germ-killing ability drops sharply below 50%. In biology labs, a diluted bleach solution (household bleach diluted to a 1:10 concentration) is typically used instead, especially if biological materials were present. Spray the surface, let it sit briefly, then wipe it down with a clean paper towel.
Check that common areas are clean too. Balance stations, shared instruments, and fume hoods should be free of vials, trash, loose paper, and aluminum foil. If you used a fume hood, make sure nothing is hanging on the hood knobs and that no uncapped containers are left inside.
Dispose of Waste Correctly
Never pour chemicals down the sink unless your instructor specifically says it’s safe to do so. Chemical waste goes into designated waste containers that match the type of material: acids with acids, solvents with solvents, and so on. Every waste container should be capped and clearly labeled with its contents. Unlabeled containers are treated as hazardous by default, which creates unnecessary work and expense for everyone.
Sharps like broken glass, razor blades, and used needles go into rigid, puncture-resistant sharps containers. Regular broken glass (not contaminated) usually goes in a separate labeled glass disposal box, not the regular trash.
If your lab involves biological materials, solid biohazardous waste must be collected in bags marked with the biohazard symbol and placed in a leak-proof container with a lid. These are later autoclaved at 121°C for at least 30 minutes before they can be discarded as regular trash. Your instructor or lab manager will handle the autoclaving, but you’re responsible for getting waste into the right container.
Rinse and Return Glassware
Dirty glassware should be rinsed before you put it away. The standard approach is a triple rinse: fill the vessel partway with an appropriate solvent (usually water, sometimes acetone for organic residues), swirl it around, then pour the rinse liquid into the correct waste container. Repeat this at least two more times for a total of three rinses. If visible residue remains after three, keep going until it’s clean.
Once rinsed, place glassware on a drying rack or return it to its designated spot. Beakers, flasks, and graduated cylinders that are still wet should be inverted on a rack so they drain properly. Don’t stack wet glassware inside other glassware.
Store Chemicals and Secure Cabinets
All chemicals need to go back to their proper storage locations, segregated by hazard class. Flammable liquids belong in a flammable storage cabinet, not on the open bench. Acids and corrosives are stored separately from oxidizers and reactive chemicals. Leaving a bottle of solvent sitting on your bench is one of the most common end-of-lab mistakes, and one of the easiest to avoid.
If your lab uses radioactive materials, these must be locked inside a refrigerator, freezer, or lockbox before you leave.
Shut Down Equipment and Gas Lines
Turn off any equipment you used. For microscopes, switch off the light source and cover the instrument with its dust cover. Stir plates, hot plates, heating mantles, and ultrasonic baths should all be powered down and unplugged if that’s your lab’s protocol.
Gas lines deserve special attention. Always shut off the main gas valve at the bench, not just the control valve on the burner itself. Turning off only the burner’s valve can leave the supply line pressurized, which creates a leak risk. Double-check gas valves before you walk away. If your lab uses compressed gas cylinders, confirm the cylinder valve is closed and the regulator is depressurized.
For fume hoods and biosafety cabinets, follow your lab’s specific shutdown instructions. Biosafety cabinets should have their interior surfaces decontaminated and their sash closed. Do not leave UV lights running unattended.
Remove PPE in the Right Order
The order you take off protective equipment matters because the outside surfaces of your gloves, goggles, and lab coat are potentially contaminated. The CDC recommends this sequence:
- Gloves first. Grasp the outside of one glove with your other gloved hand and peel it off. Hold the removed glove in your still-gloved hand, then slide your bare fingers under the wrist of the remaining glove and peel it off, turning it inside out over the first glove. Discard both.
- Goggles or face shield next. Handle them only by the headband or earpieces (the “clean” parts), not the front surface. Place them in the designated receptacle for cleaning or disposal.
- Lab coat or gown last. Unfasten the neck tie first, then the waist tie. Pull the gown forward from each shoulder so it turns inside out as you remove it. Roll it into a bundle with the contaminated side inward and place it in the laundry bin or waste container.
PPE should stay in the lab. Wearing your lab coat to the cafeteria defeats its purpose.
Wash Your Hands
This is non-negotiable, even if you wore gloves the entire time. Gloves can develop micro-tears you can’t see, and contamination can transfer to your skin during removal. Wash with soap and running water for at least 20 seconds, making sure to scrub the backs of your hands, between your fingers, and under your nails. Rinse thoroughly and dry with a clean towel or air dryer. Do this before you touch your phone, your bag, or your face.
Record Your Work
Before the details fade, finish your lab notebook entry for the session. A complete entry includes the date, your name, what you did, what you observed, and any data you collected. If you made an error in your notes, draw a single line through the mistake, then sign and date the correction. Never scribble over or tear out a page. If you’re using an electronic lab notebook, corrections are tracked automatically through an audit trail, but you should still review your entry for completeness before logging off.
Recording results while they’re fresh is far more reliable than trying to reconstruct them later. Even if your experiment didn’t go as planned, write down what actually happened. Unexpected results are still data.
Final Security Checks
If you’re the last person leaving the lab, do a final walkthrough. Confirm that all entrances are locked and windows are closed. Verify that gas valves are off, no equipment is running unnecessarily, and no chemicals are sitting out. Check that flammable cabinets are closed and secured. A quick two-minute scan of the room can prevent overnight accidents, leaks, or security breaches that would be far more disruptive than the time it takes to check.