Chemical factory Bayer Cropscience has been granted permission to store more than 70 hazardous substances on its site on the edge of Norwich, despite concerned councillors questioning whether that would create an increased risk to city families.

The company, which makes agricultural products such as pesticides, had to seek permission from Norwich City Council because of changes in what it stores at its Sweet Briar Road factory.

It submitted a five-page list of some 70 chemicals, including copper cyanide, hydrogen peroxide, bromine and methanol, which it wants to store in varying quantities.

Council officers, at yesterday's meeting of the city council's planning applications committee, said it was the first time since the factory opened in 1955 that council members had the chance to consider the risks 'posed by the operation at Bayer to the people and environment of Norwich'.

And Green councillors for Wensum ward Ruth Makoff and Rupert Read urged councillors to 'consider very carefully' what decision they made and raised concerns about odours from the factory.

Mr Read said: 'This is the first time ever that this committee has had the chance to consider these issues in the round. This is a historic day and we have an historic opportunity.

'If this factory was seeking to be built from scratch would you be inclined to build it? I put it to you that you would not.

'It is in an extremely built up area which is completely different to what was there in 1955 and even in 1990.'

But site manager David Jones said: 'At the end of the day we cannot guarantee it will be 100pc safe no matter what happens, but we can reassure you the steps we want to take look to improve what we do here and handle it in the best possible manner.

'This is the first time you have looked to consider this, but we are regularly and routinely monitored by the Health and Safety Executive and the Environment Agency on a regular basis.

'That means they visit the site several times a year and look at all aspects of operations. They are very meticulous in what goes on and in making recommendations to improve.'

Mr Jones said action was being taken to address odour and added: 'At this moment in time between 260 and 270 employees and around 150 contractors work at the site, so a rejection of this would mean those jobs would be lost from this community.'

Officers said the Health and Safety Executive had advised that the application would 'significantly reduce' risks associated with the factory and there were no reasons, on safety grounds, for refusing the application.

Members of the committee agreed to grant hazardous substance consent.