Data collection and recording

Certain accidents have to be notified to Energy Safety. These are generally high consequence accidents (for example, fatalities, serious harm, significant property damage). The obligation to notify falls on participants in the energy industry in the first instance. Notifications of gas and electricity related accidents also come from consumers and other agencies, such as Fire and Emergency New Zealand (FENZ) or local body Health and Safety Inspectors.

These notifications are collected and recorded.

  1. Electrically-related fires are not included for analysis. There is evidence that there has historically been under-reporting to WorkSafe of less significant electrically-related fires. In addition our focus has been on electrical accidents 1 other than fire.
  2. WorkSafe investigates and records gas-related accidents that involve fire, explosion, or gas ‘poisoning.' 2 Self-harm incidents such as the deliberate inhalation of LPG are excluded from analysis.
  3. The electrical accident database in use up until 2008 allowed investigators to record only one likely major cause for an electrical accident. The database used for gas investigations allowed investigators to record up to four likely causes or factors for a gas-related accident. The accident investigation database that has been in use since the beginning of 2008 allows a range of factors to be considered and identified.
  4. Natural gas and liquefied petroleum gas ( LPG) have different characteristics as fuels and differing distribution and utilisation patterns so they are recorded and analysed separately.
  5. The gas accident database contains information about fatalities, injuries, fires, explosions and minor accidents for natural gas and LPG. These accidents have been analysed for severity 3 and frequency of similar types of accidents.

Accident analysis

To identify trends and risk areas, this analysis examines data collected since 1993 on notifiable electrical accidents other than fires and both notifiable and non-notifiable gas accidents.

Since the Electricity Act and the Gas Act came into force comparisons have been made between five year periods.

This analysis includes the latest information available at the time of preparation. In some cases, the investigations are complex and may not have been completed at the time of publication. This means that each annual analysis has to review previous years’ cases when further information has been obtained.

This accident analysis does not set out to explain the reasons behind the trends and variations found. These trends may be influenced by any number of factors, including changes in the way accidents are reported, reporting level, or actual improvements in safety or safety practices. Establishing the reason behind these trends would require detailed analysis of comprehensive data that is not always available and some of which may or may not exist.

Energy Safety uses a system called Energy Safety Intelligence (ESI) which was introduced at the beginning of 2008. This system integrates case management of electricity and gas operational activities, and stores electricity and gas accident information in a single database. This system has more data fields and a more consistent classification facility than was previously used.. However, its introduction meant there were some unavoidable inconsistencies between data held on the new system and the data held on the previous systems. This, in turn, places constraints on the analysis.


1These electrical accidents are those that relate to direct contact with electricity – ie ‘shock’.

2 -  Because modern reticulated gases do not contain carbon monoxide, this typically involves exposure to harmful products of combustion.

3 - For the purposes of analysis severity is categorised broadly as ‘fatal’, ‘notifiable – injury’, notifiable – other’, or ‘non-notifiable’.