Our local harbinger of panic, death, and destruction, The Seattle Times, says that designers have planned ahead when it comes to coping with disasters that might affect the Highway 99 tunnel. That’s not to say the tunnel won’t wind up being your tomb–’cause it might. Here are five ways it could happen.5. Earthquake. The Nisqually quake of 2001 only lasted 45 seconds, but it still managed to severely damage the Alaskan Way Viaduct and vast swaths of the SoDo, Capitol Hill, and Pioneer Square neighborhoods. By being underground, the tunnel would likely be spared much of the devastation that a major earthquake would deliver above ground. That’s of course assuming the earthquake didn’t involve a massive rise in sea level that spilled water into the tunnel, drowning people like rats.Which leads us to our next disaster.4. Tsunami. Being directly adjacent to the waterfront, the tunnel could be devastated in the rare event of a tsunami. As the Times notes, planners seem ready to dismiss any likelihood of a of such an event: . . .the only known tsunami from the Seattle Fault occurred about the year 930 and generated a 10-foot wave. To breach the current seawall, which is 9 feet above the average high tide, it would require a record tsunami at high tide. Such an event might occur once in 23,000 to 60,000 years, according to consulting firm Parsons Brinckerhoff.Of course that’s not taking into consideration the affects of climate change, which could take the probability from the nearly impossible to the highly unlikely. 3. Crash. A routine car accident could turn deadly if it blocks the entrance for rescue workers to reach injured people inside. With certain crashes, every second is crucial, and while rescue workers could make use of the tunnel’s emergency exits in order to reach victims, doing so would mean they’d be without ambulances and would have to carry whatever equipment they thought they might need, then carry out the victims–a time-consuming process.2. Toxic Fumes. Now suppose that same crash involved a truck carrying toxic chemicals. A fire could set those chemicals aflame and turn the tunnel into a gas chamber. Luckily, the Highway 99 tunnel will come with a state-of-the-art ventilation system that can pump out toxic air quickly. Still, with certain chemical fumes, the room for error would be near zero, so one would have to hope that the multi-vent system touted by Seattle Tunnel Partners is everything it’s cracked up to be. 1. Fire. The #1 threat to any tunnel is fire. As the Times notes, the Mont Blanc Tunnel fire in 1999 between France and Italy killed 39 people with smoke and heat.Again, STP is relying on its ventilation system to keep smoke from being trapped inside, and on a massive sprinkler system to put out fires. “The way to deal with a fire is to put it out,” said Susan Everett, a Washington State Department of Transportation (WSDOT) engineering manager.Furthermore, gasoline tankers would be barred from using the tunnel, and the whole thing would be coated in a special fire-resistant chemical.All of these potential disasters (except possibly a flood) could be averted through the tunnel’s escape routes, which STP again is claiming are top-notch.So will you die in the Highway 99 tunnel? Probably not. But that shouldn’t stop you from developing an OCD-like fear of ever traversing such an engineering marvel (no, really, it’ll cut down on traffic for the rest of us).