For many Southern California residents who were evacuated after a chemical tank overheated, the relief of finally being allowed to return home has been overshadowed by lingering fears of living near the aerospace plant that has faced problems.

There are millions of chemical tanks around the U.S., and experts say it is exceedingly rare for them to fail as long as they are properly maintained and inspected.

Wales has recorded its hottest May day in over 80 years, with a temperature of 32.9C.