Good Chemical Practice (GCP)

'Good Chemical Practice' relates to the safe use of chemicals in laboratories: It does not apply to any other situation. It defines a MINIMUM acceptable standard for work with ALL laboratory chemicals.

For SOME laboratory chemicals no other precautions will be necessary.

This document should be read in conjunction with the full text of the University's Local Rules 'Safe working with Chemicals' and the School Safety Policy and arrangements.

Three principles underlie this document:-

  1. The quantities of chemicals in use at anyone time are small.
  2. Use and access are restricted to competent people or to staff or students undergoing a planned and supervised learning process. These people have learned, or are learning, the principles of good chemical practice (GCP).
  3. The laboratory is a controlled working environment with a number of special features designed and provided for users of chemicals.

Competence and Supervision

Chemicals may only be used by individuals with a sufficient level of competence with an appropriate level of supervision

This document is not a training manual and may not be used as a substitute for this requirement

Introduction

The aim of 'Good Chemical Practice' is the protection of people against hazardous substances encountered at work in laboratories by appropriate means of control. The underlying fundamental principle is

  • Contact with chemicals must be avoided by the use of appropriate control measures.

Laboratory Design

  • The laboratory should be easy to clean.
  • Bench surfaces should be impervious to water and resistant to chemicals.
  • The laboratory should meet published design standards. Mechanical ventilation, if available, should operate by extracting air from the laboratory to atmosphere outside the building in such a manner that re-entry of the discharged air is unlikely.

Working Methods

  • Smoking, eating, drinking, and the application of cosmetics are prohibited in areas where chemical substances are used or kept.
  • Food, drink, etc. can readily become contaminated if kept and used alongside chemical substances. It is then possible to transfer dangerous substances to the mouth or other sensitive areas of the face
  • Inhalation of vapours or skin contact with any substance is to be avoided. In general terms, fume cupboards must be used for substances which are toxic by the inhalation route even though a written COSHH risk assessment may not be required (e.g. substances allocated the risk phrases R23 -'Toxic by inhalation')
  • Work must be performed cleanly with the minimum of spilling and splashing in order to limit contamination. Suitable dispensing aids must be used and substances handled over spill trays, where appropriate.
  • Bench tops and laboratory equipment must be cleaned as soon as practicable after use.
  • This is the responsibility of laboratory staff.
  • Contaminated surfaces and equipment must be cleaned without delay.
  • Exposure to gases and vapours should be limited by covering vessels, prompt replacement of caps and stoppers to bottles and, if possible, the handling of volatile, gaseous or dusty substances in closed systems.
  • The work area should be kept tidy and substances should be put in approved storage enclosures when not in use.
  • Bottles, especially Winchester size, should be transported in special carriers.
  • The correct handling equipment should be used to transport and manipulate cans and drums.
  • The procedures for unattended experiments should be observed, and the forms kept up-to-date.

  • The appropriate equipment must be available for prompt clean-up and decontamination after spills.
  • Work which requires personal control should never be left unattended.
  • Flames and compressed gas supplies should be shut off when not in use and on leaving the laboratory.
  • The limitations on late and on lone working may be found in the University Safety Policy. Additional restrictions may be imposed by departmental local rules.
  • Hands should be washed before leaving the laboratory.

Containers and Storage

  • Containers must be properly labelled.
  • Chemicals not in use should be returned promptly to their correct storage enclosures.
  • Light sensitive substances (e.g. chlorinated solvents) should be stored in amber-coloured bottles away from the light.
  • It is prudent to keep all chemicals out of direct sunlight
  • Surplus materials should not be allowed to accumulate in laboratories.

Spillage

  • Sufficient detailed information concerning the chemicals, including methods for dealing with spillage, should be readily available. Individuals should be aware of the hazards of the materials they are using, and familiar with spillage procedures.

Waste

  • Waste receptacles should be covered, labelled, and not overfilled.
  • Incompatible wastes (e.g. halogenated and non-halogenated solvents) should be kept apart, with particular care to separate the disposal/storage of acetone and chloroform.
  • Disposal should take place in accordance with University procedures, at the earliest opportunity. In no case should they be left for the unsuspecting to inherit.

Personal Protective Equipment

  • Using personal protective equipment is not a substitute for other control measures. The purpose of personal protection is normally to prevent accidental exposure to hazardous substances. It is always necessary to match the type of protection (e.g. glove material) to the particular substance, but this is especially important if likely exposure is to be longer than accidental or, of course, if the risk to health from exposure is very high.
  • Laboratory Coats. Personal clothing must be protected from contamination by a suitable laboratory coat or overall which should be changed before becoming excessively soiled. If protective clothing is liable to become heavily contaminated, a heavy-duty plastic or rubber apron should also be worn.
  • Gloves: Wear suitable protective gloves to avoid hand contact, or the longer sleeved type if the arms are also at risk of contact with the substance.
  • Gloves should be suitable for the material being used. This information is provided by the supplier. If in doubt ask your supervisor or your School Safety Officer.
  • Gloves should be checked for holes before use.
  • Gloves and laboratory coats should be removed before leaving the laboratory area and entering offices, tea-rooms and general areas.
  • Before removal, gloves should be washed in warm detergent solution (preceded by a specific cleansing agent, if necessary).
  • Removal of gloves will be easier if the hands are first dusted with talcum powder before putting them on.
  • Suitable eye protection should be worn at all times in laboratories where the handling of chemicals is the predominant work.
  • Safety spectacles must be worn to protect the eyes from splashes when liquids are being handled. However, if the work may generate fumes, mists, dust clouds or heavy splashing then suitable goggles or a face shield should be worn.
  • Masks and respirators: Since the principal method for the control of airborne hazards is to contain the substance, respiratory protection should only be necessary In emergency situations. Filter-type respirators do not have universal applicability so that it is always necessary to match the filter to the substance. Information on suitability is available from the suppliers. If in doubt ask your Supervisor or School Safety Officer.

Accidents

  • Any personal contact with a substance should be dealt with immediately by safe and effective decontamination.
  • All accidents must be reported using the University Accident Report book. Near misses should also be reported.

Glass and Sharps

  • Many laboratory accidents arise from the handling of glassware and sharp objects. Such injuries may provide a ready means for toxic substances and biological materials to enter the body, and should be treated immediately.
  • Staff should be thoroughly trained in the cutting, bending and annealing of glass tubing and in the assembly and dismantling of glass apparatus where this forms part of their work.
  • Detergents should be employed as the normal means of cleaning glassware.
  • Cleaning techniques involving oxidising agents merit an individual risk assessment.
  • Glass and sharps must not be disposed of into plastic bags.
  • University instructions on disposal of glass and sharps must be followed

Highly Flammable Liquids

  • Vapours from highly flammable liquids are denser than air and thus tend to sink to ground level where they can spread, undetected, over a large area. IT IS ESSENTIAL TO MINIMISE THE PRODUCTION OF SUCH VAPOURS AND THE ASSOCIATED RISK OF IGNITIONBY FLASHBACK FROM A REMOTE SOURCE.
  • Fire and explosion can occur when vapours are mixed with oxygen or air in proportions that lie between the Lower and Upper Explosive Limits (LEL and UEL respectively). For most solvents the LEL is between 1% and 5% in air ,and therefore good ventilation is necessary for fire safety as well as control of toxic hazards.
  • Some substances (e.g. certain ethers and aldehydes, carbon disulphide) can be ignited at temperatures produced by hot plates and ovens. Carbon disulphide, for instance has an auto-ignition temperature only just above100C. Static electricity (which may be generated by liquids flowing through pipes or by pouring) is a possible source of ignition to any highly flammable liquid, as is any electrical fitting capable of sparking.
  • Highly flammable liquids should be stored in sealed containers in fire resisting enclosures.
  • Quantities should be kept to a minimum and the aggregate quantity should not exceed 50 litres in any workroom.
  • They must not be stored in refrigerators and freezers unless expressly designed for the purpose (units with internal lights, in general, are not).
  • Unsuitable refrigerators and freezers should carry the standard warning label.
  • Flammable substances must be kept well away from sources of ignition including naked flames, electric hot plates and non-flameproof electrical equipment.
  • Do not overheat substances with low auto-ignition temperatures, or allow their vapours to come into contact with hot surfaces.
  • Bulk dispensing must only be carried out by trained staff in a safe area.
  • Highly flammable liquids must not be poured down the sink.
  • Special risks exist during heating under reflux and distillation. School Safety procedures should cover such points as safe heating methods and the level of attendance during the procedure.