This article was reproduced with the kind permission
of the British Broadcasting Corporation
7 November 2007, 19:59 GMT
The cleaners began vomiting, itching and suffering from blistering skin following the incident in Banbury.
They came into contact with a 45 gallon barrel of waste products from the Specsavers Opticians, Bridge Street.
The firm said it was investigating thoroughly with Oxfordshire fire service and Cherwell District Council.
"We are aware of the situation and are investigating," a spokesperson for the opticians said.
"Specsavers Opticians treats an incident like this very seriously."
The emergency services were alerted at about 0915 GMT on Wednesday.
One was violently ill - vomiting, and the other started to complain
of itchy hands
Earlier Mike Smythe, deputy chief fire officer for Oxfordshire, said: "We just had two of our specialist officers in gas-tight suits enter the area, they've made tests of the substance.
"We are confident, at the moment, that the substance is in fact inert but we do need to finish off those tests results."
When the fire crews from Banbury arrived at the scene they discovered a small chemical spillage with the cleaning staff showing symptoms.
"One was violently ill - vomiting, and the other started to complain of itchy hands," Mr Smythe said.
"The barrel, as we understand it, contains waste products from the manufacturer of lenses for spectacles - basically as they shave the ends off the lenses so that they fit the frame, a quantity of white powder is produced," he added.
The powder is "common with all spectacle manufacturers across the country and that chemical is inert - plastic basically," he said.
The two men were washed down with warm water in a decontamination tent before their clothing was removed.
They were then put into sterile white paper suits before being sent to Horton Hospital.
It is understood the clothing was taken away for forensic examination.