The explosions that rocked China's northeast port city Tianjin were so deadly because first responders didn't know what chemicals they were dealing with while putting out the fire.
Of the more than 100 people killed in the blast, more than half were firefighters.
The first responders that went to address the fire at first fought the flames with water. However, the water made things worse, because the chemicals present in the warehouse were combustible when in contact with water, leading to an even bigger explosion.
That was similar to what happened in the 2013 West, Texas fertilizer explosion. Of the 15 people killed in that accident, 11 were firefighters. A later report found that the firefighters were not prepared to deal with the size of the flames, and would have been better off evacuating the area.
The cause of that fire is still unknown, though the highly-explosive chemical compound ammonium nitrate stored in the warehouse is the reason for the explosion.
In the US, fire departments are in charge of understanding what chemicals and other hazardous materials are in the area, said Ralph Stuart, a chemical hygeine officer for Keene State College. Working with the companies, the fire department can then make a plan for how to approach the possibility of a leak or explosion. That plan is contingent upon understanding how much of a substance is in a space. If the company adds more of a particularly toxic or combustible chemical, that plan needs to be revised, which is where things get tricky.
Luckily, Stuart said the US isn't too bad at accident prevention. "[Accidents are] not unheard of, but we do have a response system in place keeps these from being as bad," he told Business Insider.
Another big problem with tracking hazardous chemicals is companies write down what hazardous chemicals they have in their factories and warehouses in large stacks of paper called Material Safety Data Sheets, which they keep on site. If there were to be a fire, those papers would be near the blaze, and there wouldn't be a good way to communicate to firefighters what kinds of chemicals they're dealing with. MSDSOnline, a compliance software company, makes an online version of the MSDS records — that way, first responders can access the up-to-date information before they even get to the fire, which could help keep firefighters safer.
One of the reasons so many people died in the Tianjin explosions was because firefighters originally responded with water that reacted with the chemicals in the plant and caused an even bigger explosion.
Some mishaps are easier than others to stamp out. Stuart said one the most common and well-known accidents are chlorine leaks. Chlorine is a high profile element, so firefighters know how to deal with it.
It's when you get lesser known chemicals and leave firefighters out of the discussion about those chemicals that you run into bigger problems if an accident does happen.