Although they did not know it at the time, the source of the smoke and fire was a 10-ton meteor that was 55-feet in diameter. The meteor exploded in the sky 18 to 32 miles above ground. This set off a shock wave blast that was reportedly the strength of 10 to 30 Hiroshima atomic bombs. It was the largest meteor to hit the Earth since 1908 (which interestingly also happened in Russia). The blast reportedly injured 1158 people (including 298 children), leaving 52 hospitalized (37 of whom were released by the next day), but fortunately, no one was killed. However, if the meteor had landed at ground level, it reportedly would have probably destroyed every single building in an area as wide as Chicago and there would have certainly been a high fatality rate.
There are various ways that a shock wave blast can cause injury. First is what is known as the primary pressure wave injury, which is injury caused by the changes in the atmosphere caused by the explosion. The organs that are most vulnerable to this type of injury are those with air-fluid interfaces, such as the lungs, intestines, or inner ear. These tend to be hollow body parts. The most common type of injury from a primary pressure wave explosion is an eardrum rupture. This is why footage from people reacting to the blast shows people instantly covering their ears and reporting temporary deafness.
Then there are secondary blast injuries, in which the force of the explosion causes objects in the area to fly through the air, strike someone, and cause bodily injury. For example, this can cause a brain injury, since an object (e.g., glass, rocks, household item, wooden plank, etc.) can fly through the air at considerable force and cause blunt trauma to the skull and its underlying contents. Obviously, other parts of the body (e.g., arms, legs, internal organs) can be injured as well, as manifested by muscle tears, bone breaks, and internal bleeding. For example, one person’s finger was cut off by broken glass. One teacher was reported to have saved 44 children from glass injuries by ordering them to hide under their desks when she saw the flash. Unfortunately, the teacher suffered a serious laceration of an arm tendon. Tendons are groups of fibers that attach muscles to a bone.
A tertiary injury is when the force of the explosion causes the person to be thrown into solid object such as a wall. Clearly, this can also cause significant injury if the person is thrown forwards or backwards with enough force. It can also cause injury by being thrown down a flight of stairs, which happened to one woman, causing her to break two vertebrae (bones in the neck that make up part of the structure surrounding the spinal cord).
Lastly, quaternary blast injuries are injuries caused by the aftermath of the blast. These types of injuries usually include burns, chemical and toxic dust inhalation poisoning, radiation exposure, and crush injuries due to building collapse. There are many pictures of broken parts (wall and roof) of zinc building from the meteor blast, which is known to have hurt people.
Another health risks related to the meteor damage has to do with the event occurring over the winter due to the subzero temperatures that often occur this time of year in that part of Russia. This places people at risk of hypothermia (abnormally decreased body temperature) because of the windows that were blown out. Thus, repairing and replacing open living structures is of high priority as is finding people who are particularly vulnerable (e.g., elderly, young children, the poor) and keeping them warm with blankets, extra clothing, etc.
Hopefully, scientists will be able to develop better ways to detect meteors coming to earth and find ways to prevent them from causing significant damage and harm. In the U.S., NASA has been charged by Congress to constantly monitor the skies for incoming objects. Rather than trying to shoot down such objects, some scientists advocate for impacting the asteroids to slow them down or speed them up so they do not enter the Earth’s atmosphere. But you probably should not lose too much sleep over it. Scientists say this was a 1 in 100 year incident.
Suggested reading: Field Guide to Meteors and Meteorites