STMicroelectronics has denied using melamine in its production process, blamed by one of its former employees for causing the death of her premature baby.

The semiconductor firm refuted any responsibility for the death of 25-year-old Bethany Cassar's son, Kyle Christian, or any medical condition the young mother-to-be had suffered.

The Kirkop-based company yesterday filed a counter-protest against Ms Cassar and her partner Claude Frendo, 26, who blamed it for the death of their son as a direct result of exposure to mel-amine at work.

Kyle Christian died on November 24, a day after he was born, and a post-mortem examination established the cause of death as neonatal respiratory distress syndrome, bilateral renal cystic dysplasia kidneys and clinical prematurity.

Ms Cassar's lawyers claimed the causes of death were directly linked to her exposure to mel-amine at work.

But Malta's biggest private employer denied ever using mel-amine, saying that cleaning sheets it used had melamine resin that was "vastly diverse to melamine and has completely different properties".

A company spokesman said the resin was a "safe polymer" with thermo-setting properties, manufactured from melamine and utilised in kitchens, the nursery market, camping and fire retardant equipment. He said Ms Cassar had come into contact with melamine resin, adding that this was "very normal practice in the manufacturing process in all semiconductor plants throughout the world, including hi-tech plants in Italy, France and the US".

The counter-protest, filed by lawyers Ian Refalo and John Buttigieg, insisted that the cleaning materials were made by manufacturers of "high repute" and the material safety data sheets for such products did not include any caution of any possible detrimental effects they could cause a foetus.

The company spokesman also said that local legislation did not list melamine resin as a potential risk.

STMicroelectronics said its plant, including the Moulding Section where Ms Cassar worked, was certified and conformed to the legal obligations of the company as established by criteria from certification body Bureau Veritas. The latest certificate, of which a copy was sent to The Times, was issued in February.

When contacted, Ms Cassar said that, although she was initially told that there was no danger from her workplace, she was later moved to another section because of uncertainty about any possible effects to the foetus.

"I asked to be moved as soon as I realised I was pregnant," she said, adding that it was the smell of chemicals that had made her suspicious. Her job included placing sheets of an industrial chemical in a mould, which would then heat up and emit fumes. She claimed it took three months for her to be moved to another section after an ultrasound had revealed her 17-week baby had 15 cysts on each kidney.

The company also said that in a submission on an online health information website, Ms Cassar said her baby had died because of polycystic kidney disease and that doctors were concerned he had Potter Syndrome, where the baby's kidneys do not develop in the first few weeks of life in the womb, leading to little or no amniotic fluid.

Ms Cassar also wrote that, although doctors checked her kidneys and those of her boyfriend's for any cysts, none were found. She also expressed concern that she would have the same problem with any future pregnancies.

On this basis, STMicroelectronics argued that both polycystic kidney disease and Potter Syndrome were genetic or hereditary conditions and consistent with the terminology used in the protest as being the cause of the baby's death.

But Ms Cassar said yesterday that doctors were considering Potter Syndrome before the post-mortem was carried out on her son, who died after just 19 hours.

The company said in its counter-protest it had been generous with Ms Cassar, accepting her request to work reduced hours during pregnancy after fears that she could lose her child as a result of "genetic incompatibility". The company also allowed her to be absent from work after she had used all her sick leave. She was also deployed to four different jobs of her own choice in one year. It said there was no connection linking the baby's death to processes involving cleaning sheets and cleaning compound used by the plant and that Ms Cassar had provided no medical evidence to substantiate her allegations, which the company claimed were "completely unfounded".

STMicroelectronics said Kyle Christian's parents had made "untruthful, defamatory and libellous" allegations in the media. It called on the couple to desist from further "defaming and damaging" the company and held them responsible for damages.