Suspected chemicals in concrete cause fire spots on Son La home's yard VnExpress Authorities believe fire spots appearing on a household's concrete yard may be caused by residual chemicals in metal containers reacting with air.
Fire spots appear for several days on concrete yard at resident's home VnExpress Small fire spots have repeatedly appeared on a concrete surface in front of a resident's house in Son La during a period of intense heat. Local authorities have requested functional agencies to investigate the cause.
