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Risk Assessments/COSHH - Information

Experimental Work

It is a legal requirement that before you begin any work activity that carries a significant risk of injury or ill health (and that would include virtually any laboratory work) you must do a risk assessment. The risk assessment should consider the following: what you are proposing to do, what hazards are associated with the work, what the reasonably foreseeable injuries/ill health might be, who could be affected and what you intend to do to prevent the ill health or accident.

The risk assessment must be recorded in writing, for example on the Nanoscience form (available here (pdf)(doc)).

Some activities, such as electrical, chemical, laser and radiation work have specific legal requirements that must be met - if unsure consult your supervisor or contact the Department Safety Officer before commencing work.

Do not operate equipment such as pressure vessels, cryogenic equipment, high voltage equipment, lasers etc. unless you have received adequate instruction.

Working on potentially dangerous experimental projects alone outside the hours 8.00-18.00 is not normally permitted due to first aid response times.

If you wish to dispose of chemical waste there is a waste store outside the Cavendish stores. A key is required from the stores and 2 copies of the disposal form must be completed, one to be left with the waste and the other forwarded to the Cavendish Safety Officer. If the waste falls outside the categories normally handled, consult the Cavendish Chemical Specialist.

Control of substances that are dangerous or hazardous to health

Suitable and sufficient assessments of the risks to health and other dangers such as explosion, created by work involving these substances must be made prior to the commencement of the work.

The purpose of the assessment is to enable a valid decision to be made about what measures need to be taken to prevent, control or reduce exposure to hazardous substances, or to prevent dangerous situations from occurring or arising from work activity.

The following factors need to be considered:

  1. The substance and its characteristics - All chemicals are toxic to living organisms under certain conditions. However a highly toxic chemical will produce damage even in small amounts, whereas a substance of low toxicity is unlikely to produce any injury unless the exposure involves large quantities, or the accumulation of the substance through repeated exposure.
  2. Liquids with a high flashpoint become dangerous when the work activity raises their temperature above the flashpoint. Dust can form explosive atmospheres eg wood, flour. The flammable nature of a substance, its potential to form an explosive atmosphere, the likelihood of thermal runaway, and the presence of ignition sources should all be taken into consideration.
  3. The form in which the substance occurs - eg particulate, liquid, gas. This influences the way in which the substance is presented to the body, and hence the risk. Mixtures and preparations will also be encountered in addition to pure substances. The extent to which the properties of mixtures may differ from the properties of their individual component substances must be taken into account.
  4. The exposure - the activity, method of production or use of a particular substance influences the quantity absorbed. Consequently the number of exposures and their duration, the intervals between exposures and the total length of exposure must be taken into consideration. Due consideration must also be given to synergistic effects as a result of exposure to two or more substances at the same time or one after the other. Exposure due to any reasonably foreseeable deterioration or failure of any control measure provided should also be considered eg rip or hole in gloves worn leading to skin exposure.
  5. The workplace - consideration must be given to how and where the substance is used and under what conditions.
  6. The individual's own physical health and susceptibility to exposure must also be taken into consideration.
  7. Any by-products, emissions, residues and waste must also be considered.

Risks arising from activities involving hazardous substances must be eliminated, or where this is not possible or practicable, the risk or exposure must be adequately controlled. Where this is achieved through engineering methods (eg use of fumehoods) or items of personal protective equipment (PPE), appropriate information, instruction and training must be given in the proper use of control methods.

All persons working with hazardous substances must make full and proper use of any control measures provided and must report any defects discovered to the Departmental Safety Officer as soon as possible.

Engineering measures must be maintained in an efficient state, and must be tested annually. Records of tests must be kept.

All PPE must be routinely examined to ensure it is still safe to use. Contaminated clothing should be disposed of or cleaned as appropriate.

Safe Operating Protocols and systems must be reviewed every five years to ensure they are relevant and viable. If there is a change in activities amendments must be made and recorded.

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Hazard - a potentially dangerous event. A source or situation with a potential for harm in terms of injury or ill health, damage to property, damage to the workplace environment, or a combination of these.

Risk - the likelihood of a hazard occurring, and the possible consequences. A combination of the likelihood and consequence(s) of a specified hazardous event occurring.

Risk Assessment - a procedure (usually formalised in writing) to assess the likely hazards and risks of an activity. The overall process of estimating the magnitude of risk and deciding whether or not the risk is tolerable. A tolerable risk is one that has been reduced to a level that can be endured, having regard to legal obligations and health and safety policy.

COSHH - Control Of Substances Hazardous to Health. Government legislation stating acceptable levels of exposure etc for a particular chemical.

MSDS - Material Safety Data Sheets. Information sent out with all newly purchased chemicals. Tells you about the dangers associated with the chemical.

Maximum Exposure Limit - The maximum exposure limit approved by the HSC for that substance in relation to the specified reference period when calculated by an HSC approved method. Maximum concentration of airborne substance averaged over a reference period to which individuals may be exposed under any circumstances. Exposure must be reduced below the MEL as far as is reasonably practicable. Exposure must nor exceed the MEL. MELs are assigned when there is serious concern about possible effects on workers.

Occupational Exposure Standard/Limit - set at a level at which there is no indication of risk to health of exposure by inhalation day after day.

MELs and OELs

STELs - Short term exposure limits - where substances can cause acute health effects. STELs should prevent adverse health effects occurring from brief exposures to the substance.

Sensitiser - a substance know to cause, through an allergic reaction, a chronic adverse health effect that becomes evident in a significant number of people on re-exposure to the same substance.

Harmful - substances which, if inhaled, swallowed or absorbed though the skin, can have limited effects on health.

Toxic - substances which can cause serious acute or chronic effects, even death, when inhaled, swallowed or absorbed through the skin.

Very Toxic - substances which can cause extremely serious acute or chronic effects even death, when inhaled, swallowed or absorbed through the skin.

Flammable - a substance that catches fire easily, liquids with a flash point between 21-55 o C.

Asphyxiant - a material capable of reducing the level of oxygen in the body to dangerous levels. Usually works by displacing air in a closed environment, so reducing the amount of oxygen available to breathe. Less than 19% oxygen in air is considered dangerous. Causes unconsciousness or death by suffocation.

Irritant - a chemical which may cause irreversible inflammation on immediate, repeated or prolonged contact with skin or eyes.

Corrosive - substances which can destroy living tissue.

Carcinogen - substance that has been proven to, or is suspected of, causing cancer through immediate, repeated or prolonged contact with skin or eyes or inhalation or ingestion.

Teratogen - an agent that can cause malformations of an embryo or foetus.

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last updated 24-11-2005