In EM labs you will often find risk assessments for the use of equipment including:
- Individual microscopes
- Critical Point Dryers and other sample preparation equipment.
You will also find risk assessments for sample preparation chemical techniques including:
- Chemical fixation
- Methods for drying samples (e.g. HMDS)
A risk assessment is a formal analysis of hazards involved in a process, to determine how dangerous a process is – i.e. the risk. It incorporates measures to make it safe to do the process - the controls. Risk assessments are required to be conducted in every workplace by law. (When do you do a risk assessment? Assessments should be conducted by experienced persons, before any new process is undertaken, when changing the process or if an incident has occurred. Assessments should also be routinely re-assessed.)
Hazards are the potential dangers present in workplace task.
The risk is the overall likelihood that an injury (or other detrimental event) will occur because of the hazard.
To determine the risk, you have to look at 3 factors.
- Consequence – The most likely outcome if control measures failed and an incident occurred. (It is not the worst case scenario.) Consequences can be personal injury, environmental or economic damage. They range from Minor (e.g. first aid, small bruises) to Catastrophe (e.g. many fatalities, extensive environmental/financial cost) with several categories in-between.
- Exposure – How often the process takes place. This is not how often, for example, “you spill a chemical on yourself”, but how often you “undertake the process using that chemical”. Your exposure to a process may range from Very Rare (has never happened yet) to Continuous (occurs many times per day).
- Probability – The likelihood that the consequence you have chosen will occur while undertaking the process. Probability ranges from Practically Impossible to Almost Certain
Once individual ratings have been determined for these 3 factors, a risk rating can be calculated for the process. This risk can be calculated using a variety of systems. These include line-bar systems, number systems or risk matrices. The higher the consequence, exposure or probability - the greater the risk. Risk categories (and actions recommended) are listed below. Your resulting risk may be categorized as follows:
|Low||Risk is acceptable, it is ok to continue process, and no immediate improvements are needed.|
|Moderate to Substantial||Risk is a concern. Situation is not an emergency but procedures should be improved as soon as practicable.|
|High to Very High||Immediate corrective action is required. Process should be stopped until risk is reduced.|
With any risk assessment, additional controls should be implemented until the resulting risk is considered low (at the very least). The effect of controls (no matter what the risk rating) should be monitored and reviewed to provide continual improvements. Your aim is to produce a risk assessment document that comes out with a low risk for the process (e.g. handling your sample and generating your data). You rework the document with new ideas on how to control the risks until it comes out in this “safe” category.
Here is a list of types of control measures, from most to least effective.
- Eliminate the hazard is the first choice
- Substituting a less hazardous material, process or equipment
- Redesigning the equipment or work process,
- Isolating the hazard through engineering – separating the worker from the hazard
- Administrative controls involve minimizing exposure to a risk through the use of procedures or instruction.
- Personal Protective Equipment (PPE) is used as a last resort when exposure to risk is not or cannot be minimized by other means.
When any chemicals are involved in a process, it is good practice to complete a Chemical Risk Assessment as well as the Standard Risk Assessment. A Chemical Risk Assessment incorporates the chemical properties of all chemicals involved in the process into the assessment of the task. It includes the crucial information from the Material Safety Data Sheets (MSDS) such as hazardous properties, routes of exposure, required control measures, first aid, waste disposal and spill procedures.
Workplaces are required by law to have on hand MSDS’s for all hazardous substances – including your sample (in some cases). MSDS’s can be obtained from the manufacturer, supplier or from on-line databases. MSDS’s for unique chemicals (e.g. of your creation) or your unique samples may not exist. This is where a chemical risk assessment (produced by experts in the material – you) is crucial in keeping all those who may contact your material safe.
As many hazards in an EM lab are of a chemical nature, the Chemical Risk Assessment may be a more practical guide to a chemical process than the Standard Risk Assessment alone. Your sample is a form of chemical and you may be required to submit a chemical risk assessment. This should address these issues. You may not need to write a risk assessment from scratch. Other colleagues may have worked on similar material and their risk assessment may suit your situation. Research groups often develop sample risk assessments for submission to other labs. EM labs often have prepared assessments for common samples and you may be able to adapt these to match your sample.
Major hazards in SEM labs
|Major Hazards in SEM Labs||Actions/ Effects||Possible Controls|
|Liquid Nitrogen||Cryo-burns, Asphyxiation, Embrittlement of materials. May liquefy and concentrate oxygen to levels that can allow combustion on warming.||
|Glutaraldehyde / Formaldehyde||Toxic, corrosive, sensitizer. Vapours may cause serious damage to eyes. Environmental toxin.||
|Osmium tetroxide||Toxic, corrosive. Vapours may cause serious damage to eyes/lungs. At high concentrations or in crystalline form, it has a stronger toxic vapour effect than glutaraldehyde.||
|Sodium Cacodylate buffers||Toxic, possible skin sensitiser. Environmental toxin (contains arsenic).||
|Samples||May be toxic, corrosive, carcinogenic, irritants, oxidizers....||
|Hexamethyldisilazane - HMDS||Highly toxic; flammable; corrosive; irritant; liberates H2 gas.||
|Ethanol, Methanol, Acetone – dehydration or cleaning liquids.||Flammable; irritant to eyes; toxic (methanol); may cause dizziness.||
|Electrical hazards – High voltage equipment||Electrocution||
|Ergonomics - Microscope workstations||Muscular stains may result from extended use of equipment. Workstations employing ancillary equipment (e.g. multiple monitors, computers) may have poor ergonomics if not modified to suit individual users.||