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[ Industrial Accident of Confined Space ]
[ Industrial Accident of Chemicals ]


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The Gassing Incident
Summary
    A worker was found collapsed inside a long pipeline (about O2.2m and 120m long) located at a jobsite in New Territories while he was carrying out grinding works. This gassing incident was chiefly arisen from the accumulation of exhaust fumes generated from a petrol-fuelled portable generator inside the pipeline, thus leading to Carbon Monoxide poisoning of the deceased. He was certified dead when arrived at hospital.


Circumstance and Observations
    On date of accident, the deceased was assigned to grind a pipe-joint at specific location. He fetched a portable electric generator, a portable hand-grinder, a light bulb and other hand tools from the workshop. The generator was petrol-fuelled and it was used for supplying electricity to the grinder and to the lighting inside the pipeline.
    The deceased entered the pipeline and started his work inside the pipeline at about 10:00am in that morning. Having switched on the electric generator, he began to grind the pipe-joint. He had worked alone for a long time and was eventually found collapsed inside the pipeline at about 2:30p.m.
    A simulation test was conducted after the accident by the Inspectorate with the assistance of Government Laboratory and the Occupational Hygienists. The test was to sort out the concentration of the Carbon Monoxide so generated from the portable petrol-fuelled generator after running for a certain period of time. The result of the test indicated that the IDLH (immediately Dangerous to Life or Health) concentration of the Carbon Monoxide would be exceeded in less than one hour of continuous operation of that generator. The post mortem report also indicated that the causation of the death for the deceased was mainly due to Carbon Monoxide poisoning.
    In conclusion, the work environment so set up inside the pipeline was a confined space in which carbon monoxide fumes would be generated and accumulated from the generator using petrol as a fuel. The extent and concentration of the Carbon Monoxide so developed was so hazardous that it gave rise to risks of workman being overcome nearby inside the pipeline.


Accident Causation Model
    We have applied Heinrich's Domino Theory to represent the sequence of events as follows:

    (c) Ancestry and social environment
      - Lack of knowledge of working in confined space and safety guidelines
    (d) Fault of person
      - Ignorance of safe practice
    (e) An unsafe act and / or mechanical hazard
    -Entry into long pipeline without gas detection, ventilation and breathing apparatus
    (f) The accident
      -Carbon monoxide poisoning
    (g) The injury
      - A worker was certified dead when arrived at hospital


Preserving event data (5-P's)
    Parts
      - Petrol-fuelled portable generator
      - Portable hand-grinder
      - Light bulb
    Position
      - Point in time of current and past occurrences: 10:00am - 2:30pm
      - Position of personnel at time of occurrence(s): inside a long pipeline
      - Position of occurrence in relation to overall facility: a jobsite in New Territories
    People
      - Operations personnel
      - Management personnel
      - Technical personnel
      - People from other similar sites with similar processes
      - Safety personnel
    Paper
      - Chemistry laboratory reports
      - Specifications
      - Procedures
      - Training records
      - Nondestructive testing results
      - Employee file information
      - Production histories
      - Safety records information
    Paradigms
      - We do not need data to support RCA because we know the answer.


Analysis the Data
    We have applied the fault tree analysis to represent the root causes of this case as follows:



Prevention Recommended
    In order to obviate the accident, the following preventive measures shall be adopted:
      - It is a potentially dangerous practice to work in a confined environment where the concentration of carbon monoxide would be expected to be present to cause injurious effect to workman. As far as practicable, the electric generator using petrol as fuel should not be operated inside a confined space and near workman where only limited natural or artificial ventilation is available.
      - A safe system of work for entry into confined space shall be adopted for the job and necessary safety precautions for entry to a confined space shall be implemented. The safety precautions shall include provision and use of approved breathing and reviving apparatus, implementation of permit-to-work system and trained personnel etc.
    Legal Action
      It was found that the Regulations 6 & Regulation 9(1) of the Factories and Industrial Undertakings Regulations (Confined Spaces) Regulations were breached:
        - Under Regulation 6, no person shall enter or remain in a confined space for any purpose unless he is wearing an approved breathing apparatus, has been authorised to enter by the proprietor and where practicable, he is wearing a belt with a rope securely attached thereto and the free end of the rope is held by a person who is outside the confined space and who is capable of pulling him out of confined space.
        - Under Regulation 9(1), a proprietor shall provide and keep readily available in a satisfactory condition a sufficient supply of approved breathing apparatus suitable reviving apparatus, vessels containing oxygen, belts and ropes