The Turkana branch of the Kenya National Union of Teachers (Knut) has called for Education Cabinet Secretary George Magoha's resignation over use of a toxic chemical in KCSE's Chemistry practical.
Chairman Kenyaman Ariong'oa said the minister should take responsibility for exposing candidates to what may be health complications that could take weeks or months to detect.
Mr Ariong'oa said their independent investigation established that at least 50 examination centers were affected and 15 cases reported.
He claimed school principals who are center managers have refused to go public to avoid being victimised by ministry officials.
"More than 15 cases, including those of two principals and a police officer from Turkana East Sub-county, have been reported. [Reports indicate that people in Turkana were] affected by the xylene chemical," Mr Ariong'oa said.
Mr Ariong'oa said those affected suffered eye irritation, stomach aches and swollen lips.
He wondered why the effect of the chemical was not established before it was presented to candidates and examiners.
"A student has already been confirmed dead. How many people should die for Prof Magoha to accept that the chemical is dangerous to human beings?"
The Nation learnt that Knec directed headteachers to buy and use the deadly chemical as an alternative for cyclohexane, which was unavailable in the market.
Mr Yusuf Aremons, the county's chairman of the Inter-Religious Council, backed the calls for Prof Magoha immediate resignation.
Mr Aremons told the Nation that it is worrying that the CS is not viewing the matter as a national disaster.
The minister disputed reports that the chemical affected candidates, saying none had been affected.
Mr Aremons said, "Parents of affected candidates, examiners and even security officers are suffering. The minister should immediately resign and give room for investigations."
He further said the CS should be moved to the Defence or Interior ministries, where he can "make strict decisions and turn a deaf ear to advice and evidence".