Process of risk assessment - Department of Biology, University of York

Introduction
STEP 1
STEP 2
STEP 3
STEP 4
STEP 5

Introduction

A risk assessment for activities involving hazardous substances involves:

STEP 1: Evaluating the hazardous nature of chemical substances
STEP 2: Assess the risk
STEP 3: Identify appropriate controls to prevent or control exposure
STEP 4: Implement appropriate control measures
STEP 5: Review effectiveness of control measures and maintain control measures

STEP 1

STEP 1: evaluating the hazardous nature of chemical substances

Look at each substance

Which substances are involved? In what way are they harmful? You can find out by:

Look at the information on the label of the chemical container:
- hazard warning symbol (pictogram’)
- signal word (‘Danger’ indicates more severe hazard categories, and ‘Warning’ indicates less severe hazard categories)
- ‘hazard statements’ indicate the nature of the hazardous substance

example label

Check the Material Safety Data Sheet for each chemical

A Material Safety Data Sheet (MSDS) must be provided by the supplier if the chemical is hazardous and supplied for use at work. These are easily accessible from supplier's web-sites:

The MSDS provide details of the hazardous nature of chemical substances (link to Fisher GHS poster) and should be the starting point for a risk assessment involving these substances. However, it must be remembered that the MSDS describes the nature of the hazard (i.e. potential to cause harm) and not the risk associated with its use.

Think about the task

If the substance is harmful, how might workers be exposed during its use? By:

STEP 2

STEP 2: assess the risk

Factors affecting risk
Hazard evaluation (Step 1) only gives an indication of the potential harm that a hazardous substance may cause. In contract, assessing the risk involves making a judgement on how likely the hazardous substance will actually affect someone’s health. A high hazard does not automatically imply a high risk and a low hazard does not imply no risk. The level of risk is based on:

how dangerous the chemical is (i.e. the hazard severity level)
the exposure potential which depends on:
- how much of the chemical is used
- the physical characteristics of the chemical
- how frequently the chemical is used & how long you are exposed to the chemical each time it is used
- method: open bench / fume cupboard / totally enclosed etc. (affects route of entry into the body)

Fortunately for the vast majority of chemicals used in the Department of Biology, the quantity used is very small and the exposure time is very small so that work involving most chemicals can be covered simply by the 'Code of Good Laboratory Practice'.

Guide to assessing likelihood of a work activity causing exposure to a chemical substance

Factor	Exposure potential
	Low	medium	High
Quantity	< 1 g	1 – 100 g	>100 g
Physical characteristics	Dense solid Non-volatile liquid No skin absorption	Light, powdery solid Lyophilised material Dust-forming material Volatile liquid Poor skin absorption	Gas, Vapour Aerosol Highly volatile liquid Rapid skin absorption
Exposure time	<60 per day	< 10 min per day	> 10 min per day
Method: open bench / fume cupboard / totally enclosed etc. (affects route of entry into the body)	Mainly enclosed Low chance of mishap	Partly open Low chance of mishap	No barrier (including primary containment) Medium / high chance of mishap

Overall risk level

Once the hazardous nature of the chemical (hazard severity level) and exposure potential have been considered, the overall level of risk can be determined with the (see guide below).
This guide is designed to provoke workers to think about the relative risks associated with their work. At every stage there is a judgment involved.
In the Department of Biology there are no circumstances where significant risks are acceptable.

Risk level	Description
Level 1: Low risk	· Low exposure potential to hazardous chemical substances (does NOT include exposure to ‘high hazard’ chemicals)
Level 2: Medium risk	· Medium risk exposure potential (does NOT include exposure to ‘high hazard’ chemicals)
Level 3: High risk	· High risk exposure potential to all chemical substances · All work activities involving ‘high hazard' chemicals

If in doubt be safe, and exercise greater caution than is strictly necessary. However, be sensible and practical. It is important not to burden yourself or others with unnecessary precautions- they might introduce risks greater than the ones you are trying to control.

When the task involves very small amounts of hazardous material, with low exposure potential, the risk is low. However, the risk may be higher in a different task because the harmful substance may easily be breathed in or get onto the skin. When the task involves larger amounts of material, with higher exposure potential, so is the risk.

STEP 3

Identify appropriate control measures

General guide to appropriate controls when working with chemicals

Risk level	Risk control guide
Level 1: Low risk Low exposure potential to hazardous chemical substances (does NOT include exposure to ‘high hazard’ chemicals)	The substance may be handled on the open bench using the code of Good Laboratory Practice. Avoid inhalation (use fume cupboard if necessary) and contact with the skin and eyes (use gloves and eye protection if necessary).
Level 2: Medium risk Medium risk exposure potential (does NOT include exposure to ‘high hazard’ chemicals)	Short-term operations, e.g. weighing, may be carried out on the open bench with small quantities (<1g) and for limited times (<10 min.). All other circumstances, a fume cupboard should be used. Containers should be kept tightly sealed and spillages cleaned up immediately. All precautions of Risk Level 1 (including the code of Good Laboratory Practice also apply).
Level 3: High risk High risk exposure potential to all chemical substances All work activities involving ‘high hazard chemicals’	A specific written assessment and associated safety procedure (safe method of working) must be prepared and approved by the Group Leader and Departmental Safety Advisor before the activity can begin. All precautions of Risk Levels 1 and 2 (including the code of Good Laboratory Practice also apply).

Risk level

Risk control guide

Level 1: Low risk

Low exposure potential to hazardous chemical substances (does NOT include exposure to ‘high hazard’ chemicals)

The substance may be handled on the open bench using the code of Good Laboratory Practice. Avoid inhalation (use fume cupboard if necessary) and contact with the skin and eyes (use gloves and eye protection if necessary).

Level 2: Medium risk

Medium risk exposure potential (does NOT include exposure to ‘high hazard’ chemicals)

Short-term operations, e.g. weighing, may be carried out on the open bench with small quantities (<1g) and for limited times (<10 min.). All other circumstances, a fume cupboard should be used. Containers should be kept tightly sealed and spillages cleaned up immediately.

All precautions of Risk Level 1 (including the code of Good Laboratory Practice also apply).

Level 3: High risk

High risk exposure potential to all chemical substances

All work activities involving ‘high hazard chemicals’

A specific written assessment and associated safety procedure (safe method of working) must be prepared and approved by the Group Leader and Departmental Safety Advisor before the activity can begin.

All precautions of Risk Levels 1 and 2 (including the code of Good Laboratory Practice also apply).

STEP 4

Implement appropriate control measures

STEP 5

Review effectiveness of control measures and maintain control measures

If properly used and maintained effective control measures will ensure that exposure to substances is not significant.