CHEMICAL DISASTERS: CAUSES AND CONSEQUENCES
Dr. Anil K. Gupta Associate Professor NIDM
DM Terminology • • • • • •
Hazard Vulnerability (Exposure) Accident Disaster Prevention Emergency – On-site – Off-site
• • • •
Preparedness Response Compensation Litigations
CHEMICAL DISASTERS “Chemical disasters are occurrence of emission, fire or explosion involving one or more hazardous chemicals in the course of industrial activity or storage or transportation or due to natural events leading to serious effects inside or outside the installation likely to cause loss of life and property including adverse effects on the environment.”
CHARECTERESTICS Chemical accidents may be classified by – – – – – –
Chemicals involved, Sources of release Extent of the contaminated are Number of people exposed, Routes of exposure an Health and medical consequences.
Causes of Chemical Disasters • Explosion in a plant handling or producing toxic substances • Accidents in storage facilities handling large and various quantities of chemicals • Accidents during the transportation of chemicals from one site to another • Misuse of chemicals, resulting in contamination of food stocks or the environment, overdosing of agrochemicals
Causes of Chemical Disasters • Improper waste management such as uncontrolled dumping of toxic • Chemicals, failure in waste management systems or accidents in wastewater treatment plants • Technological system failures • Failures of plant safety design or plant components • Natural hazards such as fire, earthquakes, landslides • Sabotage • human error
Sources of Chemical Disasters • Manufacturing and Formulation Facility (including during Commissioning & Process Operation; Maintenance, Disposal and Waste Management) • Material Handling and Storage – Bulk Storages: In manufacturing facilities and isolated storages (including tank farms in Ports & Docks) – Storages of Small Containers: In manufacturing facilities, in isolated warehouses and godowns, and – Storage of Fuels (LPG Depots etc.)
• Pipelines, and • Transportation (road-, rail -, air- & waterways)
Trigger Mechanisms Process and Safety Control System Failures: • Technical errors such as design defects, fatigue and metal failure, corrosion etc.; • human errors namely neglecting safety instructions, deviating from specified procedures; • lack of information i.e., absence of emergency warning procedure, non-disclosure of line of treatment etc., • organizational errors viz. non-conductance of mock drills. etc for ensuring state of quick response and preparedness, poor emergency planning and co-ordination etc.
Trigger…… Natural calamities – The Indian sub-continent highly prone to natural disasters – These events trigger Chemical disasters. For e.g., Release of acrylonitrile at Bhuj, earthquake 2001, and Damage to Phosphoric acid sludge containment during Orissa Supercyclone in 1999.
Terrorist attacks/Sabotage
Release TYPE • Gas release • Liquid release • Two-phase flow CAUSE - Leakage - Vent - Rupture
Consequences of Chemical Disasters
Failures • Design / equipment/ system • Operability (human or management failure): • KSA • M or E (Management/ organizational) • Information/feedback
• Response time leads to scenario
Recurring Causes of Recent Chemical Accidents: Common Factors 1. Inadequate hazard review or process hazards analysis 2. Installation of pollution control equipment 3. Use of inappropriate or poorly designed equipment 4. Inadequate indications of process condition 5. Warnings went unheeded
Toxic effects of chemicals • Chemicals enter the body through the skin, eyes, lungs or digestive tract. • The rate of absorption via these paths is different for different chemicals • Effects can be local (e.g. burning or blistering of the skin, eyes or respiratory tract) or systemic, and • the pattern may be influenced by age, gender, immune state, non-comitant exposures and general fitness
Toxic effects…. • Some effects (e.g. eye and respiratory irritation or central nervous system depression) can occur within minutes or hours • Other effects (e.g. congenital malformations or cancers) may take months or years
Pathways of exposure
Public-health effects of chemicals • Stress and anxiety • Deaths, Burns/injuries and illness • Societal and economic costs
Fire & Explosion • Material characteristics • Conditions – Atmospheric condition • Internal • External
Temperature, Pressure, Wind
• Ignitability, inflammable • Explosion • Source of ignition
Inflammability • • • • • • •
Dow & Mond Index GPH & SPH Physical effects Amount Direction Flow characteristics Area/containment
Fire scenarios • • • • •
Jet Fire Vapour cloud Vapour cloud explosion Pool fire BLEVE
Fire Impacts • Heat wave (fire) • Fire lethality • Fire burns • • • •
Shock waves (explosion) Flying objects/ injuries Major damages Glass window cracks
•Core zone •Impact zone •Buffer zone
Impacts….. • • • • • •
Short-term Vs. Long-term Loss of lives Loss of economy Loss of market Law & order trouble and trauma Loss of peace and harmony
MCA • Maximum credible accident • PRA • ALARP
Thank you • Lesson: Managing a disaster like a chemical accident is not a charity or a welfare, BUT its our prime duty, its our accountability, and ITS the basic fundamental right of a person, organization, society or state.
