6. Operational control measures
6.1. General principles
6.1.1. The competent authority should ensure that criteria are established for
safety in the use of hazardous chemicals, including criteria for the measures outlined in
sections 6.4 (Elimination) to 6.9 (measures for disposal and treatment).
6.1.2. After reviewing the chemicals being used at work, obtaining information
about their hazards and making an assessment of the potential risks involved,
employers should take steps to limit exposure of workers to hazardous chemicals, on
the basis of the measures outlined in sections 6.4 to 6.9, in order to protect workers
against hazards from the use of chemicals at work. The measures taken should
eliminate or minimise the risks, preferably by substitution using non-hazardous or less
hazardous chemicals, or by the choice of technology; but where this cannot be achieved
the risks should be eliminated or minimised using good engineering controls. Other
measures such as safe working systems and practices, personal protective equipment
and the provision of information and training will further minimise risks and may have
to be relied upon for some activities entailing the use of chemicals.
6.1.3. For new work activities involving the use of chemicals, the hazards should
be identified and the risks assessed at the earliest stage when the new work activity is
being considered. The hazards and risks should be reviewed at each subsequent stage in
the development of a new process.
6.1.4. The purpose of the assessment is to enable an informed decision to be
made by employers about the validity of measures to eliminate or minimise risks from
chemicals. Employers should show that all aspects of the use of chemicals have been
considered in the assessment. Where an employer identifies risks which can or should
be eliminated or minimised, he or she should eliminate or minimise these risks as soon
as possible and by the best possible means following the order of preference in the
measures outlined in paragraph 6.1.2. A programme should be prepared to specify the
action necessary to eliminate or minimise the risks and the time for completion.
6.1.5. For complex work activities, such as the manufacture of chemicals, the
hazards of the process may be identified by breaking down the process into its
component operations; the stages for reviewing risks may include a desk study (a paper
review of the process and known risks), laboratory development work, pilot plant
operations, commissioning and full operation of plant.
6.1.6. Hazardous chemicals might be used in quantities which have the potential
to be a major risk not only to workers, but also to the population in the vicinity of the
use of the chemicals and to the general environment. The use of such chemicals should
additionally be controlled by following the objectives and procedures of the ILO code
of practice, Prevention of major industrial accidents (Geneva, 1991), and in accordance
with national law and practice.