It's not always shooters. Chemical leaks, refinery problems, and fires have all prompted authorities to ask citizens not leave their homes. Today's shutdown of Boston and surrounding towns is exceptional in scope — but the request itself isn't that uncommon.
A quick survey of Google News reports over the past two decades presented a number of instances in which municipalities or colleges called for the same sort of safety precaution that's taking place in Boston right now. The incidents we identified are plotted below.
The events can be broadly categorized. Shelter-in-place alerts driven by shootings or bomb danger (red markers), problems at oil refineries (blue), chemical leaks or spills (green), and fires (yellow). Each of the plotted points is described below:
- 7/29/1992, Westlake, LA. Ammonia refinery explosion prompts a shelter-in-place in Westlake.
- 6/10/1997, Scary, WV. Chemical train crash prompts a shelter-in-place in Scary.
- 3/3/2000, Houston, TX. Chemical plant fire prompts a shelter-in-place of various local schools.
- 11/29/2001, Marcus Hook, PA. Chemical plant release prompts a shelter-in-place of Marcus Hook.
- 8/20/2004, Cincinnati, OH. Warehouse fire prompts a shelter-in-place of Cincinnati.
- 8/10/2005, Texas City, TX. Gas-oil leak prompts a shelter-in-place of Texas City.
- 5/5/2006, Nitro, PA. Warehouse fire prompts a shelter-in-place of Nitro.
- 5/26/2006, Washington, DC. Shooter prompts a shelter-in-place of Rayburn House office building.
- 11/29/2009, Seattle, WA. Shooter prompts a shelter-in-place of Beacon Hill Elementary.
- 12/9/2009, Sterling, VA. Shooter prompts a shelter-in-place of Northern Virginia Community College.
- 8/24/2010, Mobile, AL. Ammonia leak prompts a shelter-in-place in Mobile.
- 9/28/2010, Austin, TX. Shooter prompts a shelter-in-place at the University of Texas.
- 11/10/2010, Martinez, CA. Refinery power outage prompts a shelter-in-place of Martinez.
- 12/9/2010, Escondido, CA. Explosives prompt a shelter-in-place of an area around a "bomb house".
- 4/26/2011, Texas City, TX. Power outages prompt a shelter-in-place in Texas City.
- 8/6/2012, Richmond, CA. Refinery fire prompts a shelter-in-place around a Chevron refinery.
- 10/25/2012, Texas City, TX. Hydrochloric acid leak prompts a shelter-in-place in Texas City.