Activities Involving Toxic or Corrosive Laboratory Chemicals
Hazards:
Toxic chemicals can cause ill-health or even death following exposure by inhalation, ingestion or skin contact. Such effects may arise by exposure to a single large dose or to small doses repeated periodically; effects can be immediate (acute) or become apparent only after a long period of time (chronic).
Toxic chemicals may cause specific types of disease (e.g. allergens and carcinogens) or affect particular organs or functions of the body (e.g. hepatoxins and neurotoxins). A combination of toxic chemicals may together have a greater effect than each separately and so exert a synergistic effect. Corrosive chemicals have the ability to destroy living tissue at the point of contact and so cause severe burns with permanent scarring or tissue changes. Some corrosives will also corrode inanimate materials by chemical action.
Risk Factors:
The health risks reflect both the likelihood and consequences of exposure.
Factors associated with each of these risk elements include:

The physical properties of the chemical (the risk is greatest for gases, aerosols, highly volatile liquids, highly concentrated solutions and dusty solids; high water or lipid solubility and ease of adsorption through skin, mucous membranes or conjunctiva);

The degree of hazard of the chemical which may be related to the LD
50
,
LC
50
, or occupational exposure level (ppm or mg/M 3 ) and the potential for cumulative effects (the risk is greatest if the chemical is classified as highly toxic, corrosive, Category 1 Carcinogens, Mutagens or Teratogens);

The efficiency of the experimental equipment or apparatus to confine or contain the chemical or the ability of personal protective equipment to prevent exposure (the risk is greatest if chemicals are handled in open vessels or containers or where dilution or extraction of the chemical by ventilation is not possible);

The frequency and duration of use and potential exposure and the quantity used in the experimental procedure (the risk is greatest if the chemical used continuously on a daily basis or of more than 100g or
100ml is used);

The ability to control chemical reactions to prevent the formation of hazardous by-products or intermediates, undesirable reaction or waste products (the risk is greatest if the chemicals are used which have varying or unknown purity or composition, if concentrated solutions or mixtures of reagents are used, if the order and rate of mixing of reagents is uncontrolled or there is inadequate control of reaction temperature or pressures).
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Risk Control Measures:
1. The hazards of the chemical(s) and chemical mixtures to be used must be identified from standard reference texts, from supplier hazard information sheets or from supply labels.
2. Wear protective clothing (laboratory coat, plastic or rubber apron), gloves
(generally PVC for inorganic and organic acids and bases, nitrile or highgrade PVC for organic solvents) and eye or face protection (general purpose safety spectacles or face visor or chemical grade goggles).
3. Procedures involving the manipulation of gases, volatile substances and those which may result in the formation of aerosols, sprays or dusts must be conducted in an efficient fume hood or in apparatus or equipment which provides an equivalent level of containment.
4. The fume hood performance must be validated by regular (at least annual) tests of air flow velocity and qualitative containment.
5. After working with toxic or corrosive chemicals the hands must be thoroughly washed; eating, drinking, smoking and the application of cosmetics must not be permitted where such chemicals are being used.
6.
Store toxic and corrosive chemicals according to suppliers’ instructions
(store only labelled containers so that incompatible chemicals cannot accidentally mix).
7. Dispose of waste toxic and corrosive chemicals according to suppliers instructions (chemicals may be made safe for disposal by a registered waste company.
Persons at Special Risk:
Persons routinely working with carcinogens, severe respiratory or skin sensitizers, chemicals with cumulative toxic effects or are strongly corrosive unless the safety precautions in place will prevent significant exposure.
Health Surveillance:
Health surveillance is required for those defined as at special risk.
Exclusions:
It is unlikely that this model assessment will be adequate for work with chemicals of extreme acute toxicity, substances known to be carcinogenic to man and for work with more than 1Kg or 2.5L of any toxic or corrosive substance.
Relevant Statutory Provisions and Other Guidance:
Control of Substances Hazardous to Health Regulations 2002
General and Carcinogens Approved Codes of Practice
Poisons act 1972 & The Poisons Rules 1982.
Pollution Prevention and Control Regulations 2000.
Special Waste Regulations 1996.
Chemicals (Hazard Information and Packaging) Regulations 2002.
Control of Lead at Work Regulations 2002
Personal Protective Equipment at Work Regulations 1992 and Guidance.
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