A 12-storey glass tower, dubbed a "lego monstrosity" by councillors, could be built above a seafront petrol station.
Brighton and Hove City Council planners have listed a string of reasons why proposals for the Texaco site in Kingsway, Hove, should be thrown out, including a risk of fire and explosion.
They also said building on the site could contaminate water and the proposed 92-flat tower would be too tall, too shiny and distract drivers.
The plans also include a new, smaller petrol station and a replacement forecourt shop.
Dubai-based developer Ridgewood Properties has launched an appeal after city councillors failed to make a decision on application within eight weeks.
Councillors discussed the plans on Wednesday agreeing they would have unanimously rejected them. Their comments will be considered by a Government inspector who will make the final decision.
Speaking against the application, Central Hove ward councillor Jan Young said: "Any seafront area is not for tower blocks. Flats, maybe yes, but tower blocks, no. We have heard there is a risk of fire and explosion. This is the same as a light aircraft crashing into the proposed King Alfred development - unlikely, but at the same time a possibility."
Councillor Carol Theobald, a member of the planning committee, said: "To me this looks rather like a lego monstrosity. It is over-development with petrol tanks in the basement. It would be detrimental to the lovely Regency and Victorian buildings and the architecture on the other side of the road."
Councillor Averil Older added: "Someone has put in these plans without coming here to visit the site. This is something which has come from outer space and should be sent right back there."
Councillor Francis Tonks called the building "pretty ugly" and "distinctly unsafe".
Councillors also said no commitment to achieving an eco homes rating of very good or excellent had been considered and many of the flats would have internal bathrooms, meaning more energy would be required to heat and light them.
Two thirds of the proposed 30 affordable housing units would not be big enough to meet social landlords' requirements.
Concerns were also raised about the security of a storage area for 105 bicycles and the lack of outdoor private space.
Lesley Clarke, Hove Civic Society chairman, said: "The proposal is tall and ugly and would be adjacent to buildings of character. This is gross overdevelopment of the site and needs to be looked at in conjunction with the proposed King Alfred development."
The plans are one of a number of applications to build tower blocks on Hove seafront which residents say would turn the area into a concrete jungle.
Councillors also unanimously rejected proposals for a six-storey block on the former Caffyns garage in Kingsway, Hove. An application for an eight-storey building in Vallance Gardens, Hove, was withdrawn by developers.
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