Learning from a recent incident

1
Learning from a recent incident

• This presentation consist of 6 view graphs (plus
  this header)
• Action required
• To be distributed to relevant staff and to be
  discussed HSE meetings in the context of your own
  operations
• To verify that you have a control system in place
  to prevent incidents from hydrocarbon leaks

2

• The incident
• A Natural Gas Condensate leak in one of the legs
  of an offshore production platform resulted in
  exposure to hydrocarbon vapours, causing the
  death of two operators
• Background
• The narcotic hazard of natural gas condensate had
  been identified in the Health Hazard Register
  and the Material Safety Data Sheet (MSDS)
• The HEMP analysis had identified leaks as an
  exposure threat, but indicated that normal plant
  integrity procedures should identify and
  control/repair leaks when they occur
• The HRA process and Leg Entry Procedures had
  identified the required control measures and
  emergency procedures
• Nevertheless, it appears that the hazard was
  poorly understood in the line and appropriate
  procedures and control measures were not
  implemented

3

• The hazards
• The narcotic effect of a hydrocarbon mixture
  depends on the dose and the concentrations of the
  various hydrocarbons in the mixture
• Narcotic effects occur very quickly within 2-3
  breaths.
• This can result in confusion and inability to
  take rational decisions, and finally to
  unconsciousness and death
• Narcotic effects from hydrocarbon vapours can
  occur at normal oxygen concentration in air, so
  the oxygen depletion alarm does not protect from
  narcotic effects
• Alarm levels of portable and fixed monitors are
  set as a percentage of the Lower Explosion Limit
  (LEL) alarm should trigger appropriate action,
  i.e. respiratory protection and immediate
  evacuation

4
Narcotic Effect vs Portable Monitor Reading
Corresponds to approx 50 general anaesthetic
dose required for surgical operations
Failure to respond to verbal commands
Hyper-excitation, loss of ability to take
rational decisions
Lower Flammable Limit
No Impairment of Functionality
Alarm setting for monitor
This is an example. Actual effects depend on the
nature of the hydrocarbon vapour
5

• Learning and Actions Toxic Substances in
  Confined Spaces
• Leaks of toxic substances in confined spaces can
  quickly result in hazardous concentrations in
  breathing air
• As well as direct health risks, these can result
  in confusion and inability to react properly
• Competence Assurance Systems should verify that
  the appropriate personnel and supervisors are
  fully familiar with the understanding of the
  hazards of toxic substances and confined space
  entry procedures
• Substances heavier than air, such as butane, can
  collect in low points, resulting in toxic or
  flammable pools which may not be detected by
  fixed gas heads or portable monitors as normally
  positioned
• Further guidance is provided in the Group Guide
  Confined Space Entry,which be issued in April
  2004

6

• Learning and Actions HEMP for Confined Spaces
• The Hazard and Effects Management Process (HEMP)
  should be applied for confined space activities
• The HEMP should contain the following
• Identification of the hazards
• Assessment of the risks using the Risk Assessment
  Matrix (RAM)
• Analysis of the hazards, e.g. by Job Hazard
  Analysis (JHA) and HRA as indicated by the RAM
• Necessary controls and recovery measures
• Demonstration that controls and recovery measures
  are effective
• The HEMP should demonstrate that alternatives to
  entering the confined space have been considered,
  and all reasonably practicable steps taken to
  eliminate hazards to health
• Confined space entry should be authorised and
  controlled by Permit to Work

7

• Learning and Actions HEMP for Confined Spaces
• The HEMP and JHA should also cover hazards which
  may be released into the confined space for
  reasons not directly connected with the activity,
  for example a leak from pipework
• Findings of the HEMP and HRA should be
  incorporated into operating procedures, tool-box
  talks, training etc. Cross-checks should be made
  against the HRA to ensure all health risks are
  being managed
• The HEMP, JHA and HRA should clearly specify the
  monitoring and escape procedures to be adopted.
  This should include the monitoring devices to be
  used, alarm levels, and escape and rescue
  procedures (including the use of breathing
  apparatus) if the alarm sounds