This is totally disgraceful. To leave your passengers to stew (fry, grill, boil, fume?) is not acceptable for anything other than a short period of time. No APU means either A/C unit, Bleed Air Cart, run an engine or no passengers. The pathetic excuse of "no steps" is not valid when people are suffering from heat stress - try explaining that decision to a coroner. I hope the Dutch press heap it on the pikey's airline.