1. CEE6430: Environmental Disasters (Man-Made) Man-made Environmental Disasters Can knowledge of Probabilistic methods minimize them?

2. CEE6430: Environmental Disasters (Man-Made) The Relevance Bhopal Disaster had its 20 th Anniversary A lot of Man-made disasters are caused by errors Uncertainty analyses/ Error Analysis/ Probabilistic Methods/Risk Management can all help to reduce the chance Well talk about one Man-made Environmental Disasters: Bhopal Disaster (India)

3. CEE6430: Environmental Disasters (Man-Made) Bhopal Disaster Gas Leak on December 3, 1984 – MIC (Methyl Iso Cyanate) 8000 people died, 50,000 injured Gas leaked from a Union Carbide Plant at night People fled from the poison gas in the middle of the night Main effect: Pulmonary Edema, skin and eye damage (total blindness) Secondary effect: Bronchitis, Bronchial pneumonia A Bhopal Victim

4. CEE6430: Environmental Disasters (Man-Made) How it Happened In the middle of the night. People fast asleep (many on the streets) 40 tonnes of MIC leaked from Union Carbide Plant The Plant Union Carbide still maintains Sabotage as the cause: Someone put water in the boiler to trigger a set of reactions Source: BBC

5. CEE6430: Environmental Disasters (Man-Made) Heres One Story Bhopal station was filling with panicking passengers fleeing the fumes Station Manager Mr. Dastagir was sensing something wrong (note: no one yet knew what was going on) The next train was scheduled to depart 20 minutes later He ordered the train to leave immediately (early) Incoming trains were all diverted It was Catch 22 situation. Uncontaminated passengers incoming to Bhopal could not be put at risk. Yet, those in Bhopal wanted to flee the fumes boarding as many trains.

6. CEE6430: Environmental Disasters (Man-Made) Contd. The station had instead become a scene of misery and death all around. Mr. Dastagirs action saved many lives. Unfortunately hes a forgotten Hero (died a year spending most of his remaining life in hospitals

7. CEE6430: Environmental Disasters (Man-Made) Could The Disaster Been Avoided? Probably (Bhopal lacked emergency planning – had never considered of such a scenario ) Union Carbide had a sloppy management practice (poor safety procedures). Such situations could be avoided through Rigorous Risk Assessment (Probabilistic) All kinds of possible scenarios are considered with their probabilities Joint probabilities, independence, dependence, mutually exclusiveness etc. Example: Nuclear Waste Regulatory Practice – Yucca Mountains – Groundwater Contamination.

8. CEE6430: Environmental Disasters (Man-Made) But How Exactly do We Minimise the Impact of Disasters? First, before even actual implementation of a project/plant, we consider what if scenarios. We ask then the most plausible effect of the what if Next we ask can we afford to live with it? Next we try to compute the chance, odds (odds ratio), probability (using very much the CEE6430 theory weve learnt) of those what ifs. Its impossible to consider all what ifs scenarios But good news – Computers are getting powerful to do the job – to consider error in all sources. New numerical techniques emerging, Fuzzy concepts, Optimization, AI, Error Analysis, Error Propagation

9. CEE6430: Environmental Disasters (Man-Made) More Specific Example: Hydrologic Imagine this: National Weather Service Issuing Flood Forecasts Considers only upto 100 years of return period in its probabilistic forecast What if – storm were a 500 year return period? How do we calculate the flood level (probabilistic)? Remember, we need to consider uncertainty in both rainfall and model – random processes Next question – can the city afford the damage expected from a 500 year storm? If not – what kind of proactive measures can it take (emergency measures) to minimise loss of life.