HONR 297 Environmental Models 4.2: Hazardous Materials Handling Practices and Potential Accidents

Locations of Hazardous Materials Hazardous materials can either be found at fixed locations or be transported from one place to another. Transported materials examples include: Tanker trucks on the road – semis or straight trucks. Tanker cars on freight trains. Small trucks or vans carrying drums or containers. Fuel or chemical pipelines – local or from one state to another. Ships and barges (tanker or container) – ports, rivers, lakes, or oceans. Airplanes with hazardous cargo.

Locations of Hazardous Materials Fixed location examples include bulk tank storage facilities, such as those shown at the right. Another way hazardous materials are stored is in smaller containers – typically 55 gallon drums. Image courtesy of Charles Hadlock, Mathematical Modeling in the Environment

Typical Accident Scenarios Hose ruptures during filling of storage tank. Static electricity causes spark, ignition, and major fire during material transfer. Tanker truck overturns on icy or slippery road. Tanker car derailment, tank is punctured. Backhoe ruptures underground pipeline. See p. 110 in our text for other examples.

Typical Resulting Hazards Pool Fire A pool of liquid chemical on the ground or floating on top of a water surface ignites. Hazard is from thermal radiation (heat) given off by fire. Vapor Cloud Fire Spilled chemical evaporates, forming a flammable cloud of vapor. Vapor cloud blows into surrounding neighborhood. Cloud ignites from a cigarette, stove, catalytic convertor, or other source of ignition. Possible flash fire back to source of leak.

Typical Resulting Hazards Vapor Cloud Explosion Similar to a vapor cloud fire. In this case, the cloud explodes. Typically, some sort of confinement is involved. Usually this is an “indoor” event. Flame Jet Material released from a broken pipe or tank break ignites and acts like blowtorch. Could affect nearby tanks.

Typical Resulting Hazards Boiling Liquid Expanding Vapor Explosion (BLEVE) Pressurized tank containing flammable chemical is immersed in a fire for an extended period of time. Contents of the tank are released catastrophically. Toxic Vapor Cloud Similar to flammable vapor cloud scenario. Vapor cloud itself is toxic or poisonous. Sickness or death may result from exposure. Suffocation Chemical fumes are not toxic and do not ignite. However, they do block sufficient air and oxygen, causing death due to asphyxiation.

Scenarios we will Address We will focus mainly on vapor cloud fires and toxicity risk. These types of risk are highly mobile and frequently occurring. Other types of hazards will also be touched on in the scenarios we consider. One hazard we will not address is radioactivity – this is beyond the scope of the course and such accidents are less likely to occur.

References Clip Art and Photos http://us.123rf.com/450wm/stoyanh/stoyanh1205/stoyanh120500 021/13511023-natural-gas-objects-and-icons--vector-icon-set.jpg http://www.gacchemical.com/image_upload/truck.png http://maritime-connector.com/ships_uploads/wana_bhum- 9308663-container_ship-8-140842_ship_profile_main.jpg http://i.kinja-img.com/gawker-media/image/upload/s--9F93r2Xm-- /802605820801960365.png http://www.la- croix.com/var/bayard/storage/images/lacroix/actualite/monde/exp losion-d-un-train-a-lac-megantic-au-quebec-2013-07-07- 983411/34533006-1-fre-FR/Explosion-d-un-train-a-Lac-Megantic- au-Quebec_article_popin.jpg Charles Hadlock, Mathematical Modeling in the Environment, Chapter 4.2