Councillors against plans for a liquefied natural gas (LNG) plant on Anglesey say they fear a terrorist attack or accident on the site.
Anglesey council will decide on the plans within the next three months
Amlwch Town Council voted unanimously against proposals by Canatxx LNG Ltd.
Canatxx said it would create 60 jobs on the site, where 100 people lost their jobs when The Great Lakes Chemical Corporation closed its plant in 2003.
The company said its specialist advisers had already given "appropriate consideration" to any terrorist threat.
Canatxx LNG Ltd - which now owns the Amlwch site - is based in Lancashire, and works in the oil and gas industry.
Amlwch town council chairman Eric Roberts said fears had been heightened by Home Office reports that the government is considering using soldiers to guard gas terminals and pipelines against the possibility of attacks.
"That's even more frightening, because the danger we thought was there is now 10 times more likely to happen," he said.
In a statement Canatxx said the proposals included "only minor provision" for storage of LNG.
It said the gas would be transported through a new 70-mile sea pipeline to the National Gas Transmission System near Nateby, north of Preston.
"Whether or not the proposals constitute a terrorist threat is a moot point, but one to which the company and its specialist advisers have already given appropriate consideration and amended its proposals accordingly," the statement read.
Anglesey Council is expected to make a decision on the planning application within the next three months.