The term is usually applied to workers employed in utilities, wastewater treatment plants, power plants or chemical plants such as gas extraction facilities, petrochemical or oil refineries.

Modern industrial plants are generally highly automated, with control of the plant's processes centralised in a control room from which valves, gauges, alarms and switches may be operated.

Generally, operators are assigned to a particular unit, on which they are responsible for a certain function or area of equipment.

Operators are also often responsible for ensuring work is being done in a safe manner, including managing 'permit to work' systems covering other workers.

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