The company running Wales' largest port has told people living nearby they have nothing to fear from the arrival of liquefied natural gas (LNG).
One of the terminals would be built at the Petroplus site
Two separate firms will ship LNG - gas cooled down to liquid form to make it easier to transport - from all over the world through Milford Haven.
Officials from the port authority told a meeting that LNG's safety record was "exceptionally good".
But some of the Pembrokeshire residents present said they remained unconvinced.
Ships carrying LNG will start arriving at Milford Haven by the end of 2007.
The LNG will then be fed into the UK gas supply.
Construction of two LNG terminals at the port is already under way and would turn Milford Haven into a major centre for importing up to £4bn of LNG over the next 15 years.
Those opposed to the scheme have raised fears over what would happen if there was a shipping collision or leak and LNG escaped into the environment.
But harbour master Mark Andrews told the meeting in Neyland on Thursday evening: "I would be a fool to say nothing could happen, but what we have to do is manage the risks to a tolerable level.
"LNG does have an exceptionally good proven safety record of over 45,000 voyages without any major loss of cargo.
"There has never been any member of the public injured or killed by a release of LNG from any vessel."
Milford Haven will see around 600 LNG dockings each year under the plans.
Port Authority chief executive Ted Sangster told the 50-plus residents present at the meeting that the authority had "done a large number of risk assessments".
He added that the authority had consulted leading experts in the field and listed a raft of safety measures that would be in place.
These include widening the channel through dredging and escorting every ship with tugs.
But he said the port authority would not release all the papers used in developing the risk assessments.
"We've come to a view that there's no benefit to passing over vast volumes of documents because our experience is they are misused and misrepresented," he said.
Campaign group Safe Haven, which has opposed the scheme, had asked for these to be made public and for an independent party to scrutinise the papers.
Safe Haven member David Robertson: "If we can't see a risk assessment there must be something to hide.
"I just think the people of Pembrokeshire deserve to have all the papers."
He added that he believed the Port Authority had failed to address in public what would happen if LNG did escape into the environment.
Llansteffan resident Frank Cornock said he had gone to the meeting to try to make up his own mind.
He said: "The country needs a gas supply, the government has to have it.
"It's going to be in Pembrokeshire, unfortunately we just have to have it here."