A school defended its decision to close for a day due to warm weather.
Soaring temperatures and unbearable humidity resulted in Park Lane Learning Trust, Exley, Halifax, shutting on health and safety grounds.
The decision brought criticism from some quarters - including Calderdale Council - but the school said it was left with no alternative last Friday.
The school was built less than 10 years ago but many rooms built into banking have poor ventilation.
Head teacher Stephen Taylor hopes the local authority will assist in sorting the problem at the PFI school.
Assistant head in charge of English Mrs Suzanne Leech said the temperature reached 44 degrees at 7.45 am in her room and she has previously suffered from a rash which her GP said was due to exposure to excessive heat.
“The heat sits in classrooms and is unbelievable, The humidity just hits you.”
The problem is so bad it has affected pupils’ learning and also impacts on exam conditions in the school hall.
English teacher Gail Jefferson said lessons had to be adapted to suit the conditions and when an overheated classroom is full of 25 pupils body heat adds to the problem.
Head girl and Y11 pupil Courtney Moss said: “You just can’t concentrate in lessons as you are focussed on getting cooled down.”
But, Coun Megan Swift, who has responsibility for education was critical and said: “As far as I know officers didn’t know Mr Taylor was shutting the school.”
Coun Swift added children could have been exposed to more risk if left to wander the streets.