The third-highest alert against a scorching heat wave was issued nationwide on Saturday, 18 days earlier compared to last year. 　 　The Ministry of the Interior and Safety issues the alert when the daily temperature ceiling in over 40 percent of the country reaches 33 C or higher for at least three straight days. 　 　Under the heat alert, the safety ministry is looking at measures to support workers who are vulnerable to inclement weather, including construction workers, elderly farmers and seni