Read a lab SOP, and complete a simple risk assessment using likelihood, severity and the hierarchy of controls.
Awareness level only. This lesson explains the ideas so you recognise them. It does not qualify you to do this work. Before you handle chemicals, biological materials or lab equipment for real, you need the training your employer or institution requires, and you must work under supervision until they sign you off.
Why it matters
Labs run on written procedures. A standard operating procedure (SOP) tells you exactly how to do a task safely and consistently. A risk assessment is the thinking that produced it: what could go wrong, how likely and how bad, and what controls bring the risk down. In the US, OSHA's Laboratory Standard (29 CFR 1910.1450) requires employers to have a written Chemical Hygiene Plan that includes SOPs for work with hazardous chemicals. Clinical and regulated labs (CLIA, GLP, GMP) also depend on SOPs for quality, not just safety. You will read SOPs from day one, and with experience you will help write and review them.
What an SOP looks like
A typical lab SOP includes:
- Title, scope and purpose: which procedure, which lab, which materials.
- Hazards: chemicals, biological agents, equipment, energy (heat, pressure, electricity, lasers).
- Controls and PPE: fume hood or BSC, PPE list.
- Prerequisites: training required, approval needed, working alone rules.
- Step-by-step procedure.
- Waste disposal.
- Emergency procedures: spills, exposures, fire.
- Revision history: author, approval, date.
How to follow an SOP
- Read the whole SOP before you start, not step by step as you go.
- Have the materials, PPE and controls ready before step 1.
- Follow it as written. If a step seems wrong, unsafe or impossible, stop and ask; do not improvise.
- Check you have the current version.
- Report problems so the SOP gets fixed.
Risk assessment: the core idea
Risk combines how likely a harm is and how severe it would be. A common tool is a 3x3 (or 5x5) matrix:
| Likelihood \ Severity | 1 minor | 2 moderate | 3 serious |
|---|---|---|---|
| 3 likely | 3 | 6 | 9 |
| 2 possible | 2 | 4 | 6 |
| 1 unlikely | 1 | 2 | 3 |
Scores of 6 to 9 are high and need strong controls or a different method; 3 to 4 are medium; 1 to 2 are low. Your institution's scale may differ.
The American Chemical Society teaches the RAMP framework, which is easy to remember:
- Recognise the hazards.
- Assess the risks.
- Minimise the risks (controls).
- Prepare for emergencies.
Worked example: heating a solvent
Task: heat 200 mL of ethanol to 60 °C on a hot plate to dissolve a sample.
| Hazard | Likelihood | Severity | Score | Controls | Residual |
|---|---|---|---|---|---|
| Ethanol vapour ignites | 2 | 3 | 6 | heat in a fume hood; use a water bath or heating mantle instead of an open hot-plate surface; keep ignition sources away; smallest volume needed | 1 x 3 = 3 |
| Splash to eyes | 2 | 2 | 4 | splash goggles; add sample slowly; do not overfill | 1 x 2 = 2 |
| Burn from hot surface | 2 | 2 | 4 | heat-resistant gloves; "hot" sign; let cool before moving | 1 x 2 = 2 |
Prepare: know where the fire extinguisher and safety shower are, and do not work alone. Notice that the strongest control for fire risk is changing the method (water bath, smaller volume), which sits above PPE in the hierarchy of controls.
When to reassess
Repeat or update the risk assessment when:
- you scale up (more volume, higher temperature or pressure),
- you change a chemical, concentration or piece of equipment,
- something went wrong (an incident or near miss),
- or a new person will do the task.
Scaling up is a classic cause of lab accidents: a reaction that was harmless at 1 gram can run away at 100 grams.
Who signs off
You can and should think through risks yourself, but approval belongs to your supervisor or principal investigator, the Chemical Hygiene Officer, and, for biological work, the biosafety officer and Institutional Biosafety Committee. Some hazards (particularly hazardous substances, high-powered lasers, radioactive materials) need specific prior approval.
Common mistakes
- Treating the SOP as optional once you feel experienced.
- Improvising when a step does not fit, instead of stopping to ask.
- Doing the risk assessment after the work.
- Relying only on PPE when a method change would remove the hazard.
- Not reassessing after scaling up.
Quick recap
- SOPs tell you how to do a task safely; read the whole thing first and follow it as written.
- Risk = likelihood x severity; use a matrix and the hierarchy of controls to bring it down.
- RAMP: Recognise, Assess, Minimise, Prepare.
- Reassess when anything changes, and get approval from the right people.
Official source: OSHA Laboratory Standard, https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1450 (Checked on 2026-10-23.)
Try it
Open the Do tab and complete a risk assessment for a fictional procedure on paper.