---
title: "Risk Assessment for a Reaction Nobody Has Run Here"
description: "The reactions that hurt people are the unfamiliar ones. A written assessment forces the questions in advance: what is the worst credible failure, what would trigger it, what stops it spreading and wha"
canonical: https://lightmysky.com/learn/science/risk-assessment-for-a-reaction-nobody-has-run-here-mt_CdotJQjdka
source: https://lightmysky.com/learn/science/risk-assessment-for-a-reaction-nobody-has-run-here-mt_CdotJQjdka.md
retrieved: 2026-09-12
---

> **Agent view.** This is the Markdown twin of the page, for tools and assistants.
> When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md
> API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md
> Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt
> Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json
> Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`.

# Risk Assessment for a Reaction Nobody Has Run Here

The reactions that hurt people are the unfamiliar ones. A written assessment forces the questions in advance: what is the worst credible failure, what would trigger it, what stops it spreading and what does the person doing the work need to know.

Subject: Science · Area: Chemistry · Ages 23 to 24
Page: https://lightmysky.com/learn/science/risk-assessment-for-a-reaction-nobody-has-run-here-mt_CdotJQjdka

## Ready when they can

- Finds the hazard data for a reagent and translates it into handling and containment decisions
- Identifies the worst credible failure for a stated procedure and the condition that would cause it
- Specifies the controls in order, from substitution through containment to protective equipment
- Writes a stop condition that says when to abandon the experiment rather than adjust it

## Lesson: Assessing a reaction you have never run

Start from the hazard data for every reagent you will touch. Look up what each one can do to skin, airways and surroundings. Then turn each hazard into a handling choice: how much you use, where you use it, and what shields you from it.

Next name the worst credible failure for your exact procedure. A pyrophoric reagent that meets air can catch fire, and slipping low temperature control can let it happen. Write the failure and its trigger side by side.

List your controls in priority order. First try substitution: a safer reagent or a smaller scale. Then containment: closed vessels, inert gas and shields. Protective equipment comes last, because it guards only the worker and not the room.

**Tip.** End with a stop condition you will obey. State the reading or sight that ends the run, such as a temperature drift or unexpected smoke. When it appears, you abandon the run instead of adjusting it.

**Recap.** Read the hazards, name the worst failure and its trigger, stack controls from substitution down to protective gear, and fix the line where you stop.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [Designing a Safer Process: Hazard, Scale and Waste](https://lightmysky.com/learn/science/designing-a-safer-process-hazard-scale-and-waste-mt_5zhSYCYU_o)
- [Characterisation Standards: What Counts as Proof of a New Compound](https://lightmysky.com/learn/science/characterisation-standards-what-counts-as-proof-of-a-new-compound-mt_WKhYUq-eyd)

## Opens up

- [Writing a Research Proposal: Question, Feasibility and Milestones](https://lightmysky.com/learn/science/writing-a-research-proposal-question-feasibility-and-milestones-mt_RYEXqgkeEU)