Specify which chlorine is involved
ILO and WHO ICSC 0126 identifies molecular chlorine, CAS 7782-50-5. It occurs as a gas or liquefied gas under pressure. It must not be confused with hypochlorites, chloramines or other chlorinated compounds.
This distinction matters in water treatment, industrial installations and cleaning services. Review product documentation and substances potentially generated by the process, not just the trade name.
Consider acute effects
Chlorine can cause serious eye and respiratory injury. Some respiratory effects may appear after a delay. It is also an oxidiser: although not combustible, it can intensify combustion of other materials.
A leak can quickly reach a dangerous concentration. Odour intensity is not a reliable measure of safety; the absence of immediate discomfort also cannot rule out significant exposure.
Eliminate unplanned mixing and interventions
Spain’s Royal Decree 374/2001 requires assessment of use, storage and handling conditions, including combinations of agents. Incompatibilities must be addressed through segregation, identification and appropriate procedures.
Do not improvise mixtures or product changes in cleaning or treatment operations. Training must enable people to recognise when an operation falls outside the procedure and must stop pending instructions.
Control the emission source
Closed systems, suitable connections and maintenance reduce the likelihood of release. Ventilation and detection must be designed for the scenario rather than assume a large room will disperse any leak.
Control must cover container replacement, equipment work and abnormal conditions. Checking normal operation does not demonstrate that every intervention phase has been addressed.
Assess short-duration exposure
The occupational hygiene strategy must consider brief operations and potential peaks. Applicable values and reference periods can be checked in the INSST LEP database and relevant legislation.
An average that does not represent the critical task can conceal the problem. Distinguish personal exposure measurement from leak detection systems: they provide different information and require their own criteria.
Organise reporting and assistance
Emergency instructions must define alerts, safe withdrawal, isolation and notification of specialist services. Approaching to locate or control a leak is not a task for people without specific training and equipment.
Inform healthcare personnel of the substance involved and any possible exposure. After the incident, review causes, controls and return conditions. The procedure must prevent others entering to help without understanding the danger.
Hypothetical example: a supply change
A site changes supplier for a water-treatment product. Before use, it checks composition, equipment compatibility and the receipt procedure rather than assume all products can be used in the same way.
Review identifies a connection operation requiring different instructions. The procedure is adapted and staff informed before the new supply is introduced.
