Also chemicals - there may appear really extremely toxic poisons, placed under the ground surface, tens of kg, much of that able to evaporate in gaseous phase.
Pia kemikali - kunaweza kuonekana sumu kweli sana sumu, kuwekwa chini ya uso wa ardhi, makumi ya kilo, sehemu kubwa ya kuwa na uwezo wa kuyeyuka katika awamu ya gaseous.