Lecture 10: Technological Hazards
• Can vary from a single toxic chemical accident to an entire industry (ie. nuclear energy)
• Other examples include exposure to….
• Hybrid disasters fit into this category
o Ex. An earthquake that causes an oil or chemical spill from a pipeline
• Technological disasters involving the environment are included in this category as well
o Ex. sinking of the titanic, explosions of the Challenger and Columbia space shuttles
• Typically, the death toll from technological hazards is relatively low.
• Vulnerability is greatest for those involved in industry or transportation systems.
• Workers in resource industries in hinterlands are at higher risk (ie. Miners)
Types of Technological Hazards
• Extreme Hazards
o widespread and long term (nuclear accidents)
o cumulative effects (pesticides)
• Rare Catastrophes
o airplane crashes
o mine collapses
o automobile accidents
• These are conditions that worsen slowly over time as exposure to a concentration increases.
• Eventually, the concentration reaches a threshold critical to human health.
• Situations related to this exposure to pesticides, acid precipitation, groundwater contamination and
Calculating Risks of Technological Hazards
• Largescale Structures (buildings, bridges, dams):
o Risk is defined as the probability of failure during the lifetime of the structure.
• Transportation (road, sea, rail):
o Risk is the probability of death or injury per km travelled
• Industry (manufacturing, power production):
o Risk is the probability of death or injury per person per number of hours exposed
• The primary source of radon gas is from the natural
decay of uranium in rock and soil.
• When radon is inhaled it then decays to polonium and
lodges in the lungs where it damages tissues.
• It is the 2 leading cause of lung cancer in North
• Radon becomes a hazard when it is released into our
living space. • It is difficult to detect because the gas is odourless, colourless and tasteless
• 5 to 10% of homes have potentially high radon levels
• Radon detectors are commercially available in areas where it is of greater concern.
• The gas can move quickly through nonsaturated soil and can seep into homes.
• Basements are at higher risk especially in winter due to reduced air circulation
• The pathways of radiation include inhalation and, ingestion (food, water).
• The impact can be direct (effects are evident within days of exposure) or delayed and chronic
• The impact could also be indirect in the form of genetic effects
• A person may not experience effects but may pass them on to their offspring in the form of
chromosomal changes or birth defects.
Sources of Radiation
Mining of Uranium
• In Canada, uranium is mined in northern Saskatchewan and northern Ontario.
• Mines produce wastes known as tailings that can be a radioactive hazard
Production of Electricity
• Uranium is used in nuclear reactors
• Most nuclear reactors in North America are located in the eastern half of the continent.
• They must be near sources of coolant (rivers or lakes)
• They must be located near a market for electricity (eastern North America is much more populated).
• Nuclear is considered a clean source of energy because it does not emit the greenhouse climate change
• A nuclear meltdown is an informal term for an accident that results in damage from overheating.
• It occurs when the heat generated by a nuclear reactor exceeds heat removed by cooling systems.
• In a meltdown, fuel rods turn to liquid and the walls of the reactor core could melt from extreme heat
• The hot liquid could melt through the bottom of the reactor and seep into the soil
Three Mile Island Accident
• This is the worst nuclear disaster in U.S. history; it occurred on Mar. 28, 1979
• One of the two reactors on Three Mile Island in central Pennsylvania experienced a partial meltdown.
• It was caused by a failure of a valve that controlled cool water entering the reactor core.
• There were no direct injuries; minor amounts of radiation were released around the site.
• This is the worst nuclear disaster in world history; it occurred on Apr. 26, 1986.
• The accident was a result of a flawed design, operator error and disregard of safety regulations
• An explosion at the plant caused the immediate deaths of 30 workers.
• An estimated 2500 deaths were caused by the disaster in the years after, many from thyroid cancer.
• The combined concern over Three Mile Island and Chernobyl halted nuclear development for a time. • However, concern over greenhouse gas emissions has created a greater demand for cleaner sources of
• For example, Ontario is committed to closing all coal power plants in the province by 2014
• To meet this objective, the province is investing in refurbishing existing nuclear reactors and is
planning to build new nuclear reactors as well.
• The Titanic was a passenger liner that struck an iceberg and sank on its maiden voyage (Apr. 15,
• The ship left Southampton, England on April 10 and was bound for NYC with 2224 passengers
• The ship was designed using advanced technology and was believed to be unsinkable.
• The death toll was 1517; the high number was due to the lack of lifeboats fro all passengers
• The wreckage was found by sonar in 1985 at a depth of 3.8 km
• A lookout on the ship spotted an iceberg in the ship’s path at 11:40pm and alerted the captain.
• 37 seconds later, the ship struck the iceberg.
• 18 lifeboats were launched and Titanic sank at 2:20 am
• The carpathia arrived at 4:10 am and picked survivors from the lifeboats
• Oil spills most commonly occur in marine areas but can also occur on land due to pipeline bursts.
• The environmental impact can be devastating and cleanup can take months to years.
• Oil penetrates into bird feathers and mammal fur reducing their ability to insulate
• Animals and birds are left vulnerable o temperature changes
and become less buoyant in water
Exxon Valdez Oil Spill
• This spill was caused by an oil tanker striking a rocky reef off
the south coast of Alaska on Mar. 24, 1989.
• This region is an important habitat for salmon, seals, sea otters
killer whales and seabirds
• 75 million litres of oil was spilled; the remote location made
recovery efforts difficult.
• It remained the worst oil spill in North American history until
the Deepwater Horizon Oil Spill.
Deepwater Horizon Oil Spill
• The spill was caused by an oil rig that exploded in the Gulf of
Mexico on Apr. 20, 2010.
• 11 workers died in the explosion that was caused by methane
gas rising up a drill pipe
• Approximately 8.5 million litres of oil escaped from the well
every day for 5 months.
• After several failed attempts, the well was finally capped with
cement on Sep. 19, 2010
• The spill caused extensive damage to wetlands and beaches along the U.S. Gulf Coast.
• The tourism industry faced severe economic loss during the summer of 2010. • The U.S. federal investigative report ultimately blamed the BP oil company for the disaster. The
report found that the company:
o made a series of costcutting choices on maintenance
o did not have a proper system in place to ensure safety
• The most wellknown recent example of infrastructure failure in North American occurred in
Minneapolis on Aug 1. 2007
• A highway bridge over the Mississippi River suddenly collapsed during evening rush hour killing 13
Minneapolis Bridge Collapse
• The cause was deemed to be excessive weight from vehicles and construction equiptment
• The bridge supports were not of proper thickness and an extra