Leetsdale, PA
This company made chemicals used for fracking.
Allegheny County officials initially issued a "shelter in place" warning for residents, meaning they should stay in their homes. But shortly after noon, hazmat team members went door to door telling residents to leave.
These fracking chemicals are toxic.
(http://a57.foxnews.com/global.fncstatic.com/static/managed/img/U.S./876/493/billowsmoke21.jpg?ve=1&tl=1)
Like the refinery fires in Texas. Placing industry plants in close proximity to residential/institutional locations is asking for trouble.
The reality is that although these occasional fires do cause extensive damage to the business, people in surrounding areas are generally not harmed. There is a bit of an inconvenience but life goes on.
Here are the two chemicals that were mentioned as being involved in this fire. Ammonium persulfate is an ingredient in hair bleach. Sodium chlorite is an ingredient in toothpaste and mouthwash. In this case both were to be used in the production of hydrofracturing compounds. but as you can see these chemicals also have uses in consumer goods.
The key thing to think about when it comes to chemicals is the concentration. Many chemicals that are benign or beneficial at low concentrations can kill at high concentrations. When a gas well is fracked, these chemicals are diluted to the point where they pose no risk whatsoever.