Chernobyl disaster is the result of pollution by
Radioactive waste
The Chernobyl disaster in April 1986 at the Chernobyl nuclear power plant in in Ukraine was the result of a flawed reactor design that was operated with inadequately trained personnel. The resulting steam explosion and fires released at least 5% of the radioactive reactor core into the environment, with the deposition of radioactive materials in many parts of Europe.
The metal does not give H2 on treatment with dilute HCL is
The gas that usually causes explosions in coal mines is