The provided article text does not contain the actual body content for this story — only the headline and a list of unrelated Daily Mail homepage links (covering topics such as wildfires in Bordeaux, a Ryanair incident, an ISIS attack in the US, and various celebrity and crime stories). As a result, no specific details about the "lethal danger" referenced in the headline — which appears to concern a summer health or safety risk affecting American holidaymakers — are available to summarise accurately.

Without the full article text, it is not possible to responsibly report on the nature of the danger, the scale of the risk, or any expert commentary that the piece may contain, since doing so would risk fabricating details not actually present in the source material provided.