Water boffins dealt a blow by "vociferous" locals hope to shore up support to turn vacant field into a new storage yard.
But angry neighbours are complaining that this will shift floodwater onto their land.
Biddisham-based SDS has mailshot residents and businesses saying the yard is needed so it can stock more of its popular void formers, used to create gaps in materials like concrete during construction for pipes or other fittings.
The firm, part of the Hinkley Point C supply chain, failed to convince Sedgemoor District Council's development control committee of the merits of letting it build a new factory, offices and storage yard at its Castle Mills base last year.
The firm blamed a "small and vociferous group of local residents" for persuading councillors and its appeal will be heard later this year.
Managing director Patrick Cullen said: "I want SDS to remain in Biddisham but we desperately need more space to store our finished products.
"We also want to increase current staff from 70 to around 100 but we don't have the space to accommodate them.
"It would be a disaster if a small group of residents thwarted these plans as well."
The new storage yard, he said, would temporarily ease problems in meeting current customer demand.
However, neighbours have commented to Sedgemoor so far that the vacant field earmarked for the yard regularly floods and concreting over it will merely send water elsewhere.
The deadline to comment on the plan (03/13/00004) on www.sedgemoor.gov.uk under planning and building is Friday, April 19.
