Laser: Device which amplifies light and usually produces an extremely narrow intense beam of a single wavelength. Light Amplification by a Stimulated Emission of Radiation.
		LD50: Stands for lethal dose 50, an index of acute toxicity established by dosing animals (usually rats) until 50% of the test population dies. Doses may be established for oral, dermal or inhalation exposures eg LE50(concentration).
		Leadership: A social process in which one individual influences the behaviour of others without the threat of violence.
		Learning: Relatively permanent changes in a person’s behaviour as a result of experience. See Classical Conditioning and Operant Conditioning.
		Ledgers: The horizontal metal poles which connect the outer and inner standards of a scaffold structure and support the transoms.
		Legionellosis: A type of pneumonia caused by the bacteria Legionella Pneumophila. The organism is usually transmitted in contaminated water aerosols. Occupational groups at risk include water system maintenance engineers and workers in air-conditioned buildings although many documented exposures of the general public exist.
		Legionnaires Disease: See Legionellosis.
		Legitimate Power: The ability to influence the behaviour of people because they believe you have a right to give orders and they are under an obligation to follow them.
		LEP,d: A measure of the average sound pressure level, measured in dB(A), for the time period of a standard working day (ie 8 hours).
		Leq: A measure of the average sound pressure level, measured in dB(A), over any time period. Note: Leq of 8 hours is equivalent to LEP.d.
		LEV: Local Exhaust Ventilation.
		LFL: Lower Flammable Limit.
		Licensed Waste Manager: One who is in possession of a licence under s34 of the Environmental Protection Act.
		Lifting Accessories: Work equipment for attaching loads to machinery for “lifting”. This definition includes: slings, shackles, swivel or eyebolts, clamps, lifting magnets and lifting beams.
		Light: Visible electromagnetic radiation which directly causes visual sensation. The conventional wavelength limits of light are 380nm to 760nm.
		Light Absorption Instrument: A direct reading instrument for particulates which compares the colour intensity of deposit against a standard.
		Light Guard: See Photo-electric Device.
		Light Scattering Instrument: A direct reading instrument for particulates based upon the Tyndall beam principle in which the air to be sampled is passed through an intense light beam. The light is scattered by the particles and the intensity and frequency of scattering is monitored by photo-multipliers which gives an instant readout of the number of particles in a given size range which, when related to the flow gives a number concentration for that size range.
		Likelihood: A qualitative description of probability or frequency.
		Liquid Adsorber: Sampling head which allows contaminated air to be drawn through a suitable solvent contained in a glass or plastic ‘bubbler’ or impinger. This technique is sometimes known as solvent scrubbing. See Liquid Adsorption.
		Liquid Adsorption: Collection technique for airborne gas and vapour sampling which involves drawing air through a solvent medium contained in a sampling head. The gas or vapour present is adsorbed into the solvent and can then be analysed for substance identification and concentration levels.
		Liquid-Solid (Absorption) Chromatography: The liquid mobile phase (ie mixture A and B) is passed through a column packed with silica gel or alumina. Liquid - Liquid (Partition) Chromatography. The mobile phase is passed over a thin layer of liquid held on the surface of a porous inert solid such as paper in water. The process is sometimes known as ‘thin layer’ or ‘paper’ chromatography. High Pressure Liquid Chromatography (HPLC). Separation is achieved by reducing the particle size of the stationary phase and forcing the mixture through at high pressure, hence HPLC.
		Load: For LOLER this includes any material, people or animals that are lifted by lifting equipment.
		Local Effects (Health): The action of a chemical, biological or physical agent at the site of contact such as the skin, mucous membranes of eyes, nose, mouth, throat or respiratory or gastro intestinal tract.
		Local Exhaust Ventilation: Mechanical extraction ventilation designed to intercept contaminants at source and remove them from the workplace before people are exposed to them.
		Lock-off System: A device or procedure using one or more hasps and locks which achieves the physical isolation of electrical or mechanical power.
		LOLER: Lifting Operations and Lifting Equipment Regulations
		Loss: The net summation of damage and personal injury resulting from an accident.
		Loss Control: A management system designed to reduce or eliminate all aspects of accidental loss which lead to a wastage of company or organisation assets. Any negative consequence of an accident event.
		Loss Prevention: The application of engineering techniques in order to reduce accidents which result in personal injury and damage to property or products. (Institution of Chemical Engineers).
		Low Explosive: Low explosive material whose propagation occurs by deflagration often producing large volumes of hot, smoky gas.
		Low Pressure (electrical): Pressure in a system (UK) normally not exceeding 250 volts where the electrical energy is used.
		Lower Flammable Limit: The lowest concentration of fuel that will just support a self-propagating flame.
		Lyme Disease: An arthritic condition associated with skin rashes, fever, and sometimes encephalitis caused by a spirochaete which is transmitted by a tick bite.
		Lymphatic System: System in which Lymphocytes operate.
		Lymphocyte: A cell, which forms part of the human immune system, which recognises antigens in the human body and manufactures antibodies, or deals directly with the antigen to combat the danger they present.

Disclaimer:
Whilst every effort has been made to ensure the accuracy of the information contained in this book opinions may vary regarding some concepts. The Key Consultancy Ltd and Safety and Health Practitioner accept no responsibility for any loss arising from reliance on this content and readers should take steps to verify interpretations to their own satisfaction if there is doubt.