Millions in US face extreme-heat threat as experts urge better protections

Recommendations include heat forecasts and outdoor-worker safeguards to prevent thousands of deaths and injuries

Millions of Americans face the threat of dangerous heatwaves in the coming weeks with another summer of record-breaking temperatures forecast to hit the US.

Most of New Mexico and Utah - alongside parts of Arizona, Texas and Colorado - have the highest chance (60% to 70%) of seeing hotter-than-average summer temperatures, according to the National Oceanic and Atmospheric Administration (Noaa). In addition, the entire north-east - from Maine down to Pennsylvania and New Jersey - as well as a large stretch from Louisiana to Arizona, Washington and Idaho, have a 40% to 50% chance of experiencing above-average temperatures from June through August.