So something interesting happened the other day in China. Folks in Xiangdu, located in China’s Guangxi province, were rather surprised to have a piece of a Long March orbital-class rocket fall into their backyard.
Nobody was injured and the chemical cloud dissipated quickly as there was only trace amounts of fuel left in the tanks.
For reference, it was one of the smaller strap-on-boosters on the sides of the main stage:
Like most older rocket designs, the Long March uses Dinitrogen tetroxide and Unsymmetrical dimethylhydrazine for fuel, this might sound nutty when you have fuels like kerosene or hydrogen handy, but these two chemicals are hypergolic, meaning they ignite instantly when they come into contact with each other. From an engineering, it's simple and reliable and don't need to be chilled like oxygen and hydrogen. But they provide a bit less thrust, hence the need for the side-boosters.
Now, the problem here isn't the toxic fuels used (you get far more pollution from an oil-tanker springing a leak since when the fuel is burned it's toxins are pretty much gone), the problem is the location of the launch site, deep in the heart of China.
As you can see on this map, Xichang doesn't have the traditional ocean nearby to dump it's spent rockets into after launch like you'd get from Canaveral, Kourou or Tanegashima. After launch, the pieces will strike land somewhere downrange. Normally this isn't a problem, as most of these landlocked launch sites have vast areas of government-owned land downrange where the rocket stages can flop to the ground without hurting anyone. Launches from Baikonur land out in the plains of Kazakhstan and Plesetsk's rockets usually end up wedged into the trees of Siberia.
(There's actually a pretty unique scrap market in Kazakhstan. Farmers, like real life Jawas, track down and dismantle stray boosters for parts and scrap to sell~! Not like Roscosmos is gonna reuse potentially damaged parts again anyway, is not safe~!)
It's not generally a problem, but when it becomes one it gets noticed and people immediately jump on the finger-pointing bandwagon as if this was an intentional bombing or something. Simply put, it's a common thing, just rarely this close to a population centre. And, to my knowledge at least, never before recorded. So I just thought I'd tell ya about this neat bit of rocketry that people aren't really aware of~