Suffolk County Executive Steve Bellone issued an order Friday that "no person, except authorized emergency personnel" can use a "private boat or vessel" to access Fire Island.
The order is in effect for five days, Suffolk police announced in a news release.
Bellone's order comes the same day the Town of Islip reinstated a mandatory evacuation for category 1 hurricane flood zones for all Fire Island communities within the town's boundaries.
Officials said ongoing assessments by the town, Suffolk County and hazmat personnel have led them to determine that Fire Island is unfit for reoccupation, and will remain unfit for several weeks. Across the barrier island, dozens of houses have been destroyed and many more have been damaged and are structurally unsound, officials said. And floodwaters that still linger there are mixed with storm debris, fuel, oil, and, in some cases, sewage.
After a few structural fires flared up in Ocean Beach in the last two days, officials are also worried that more human activity will inevitably lead to more fires -- and with a damaged water supply system on the island, firefighting crews aren't equipped to fight blazes.
Town docks are not open to the public, officials warned. Any citizen caught trying to reoccupy Fire Island will be arrested, a town spokeswoman said. The bay side of the island is being patrolled by Islip harbor police and Suffolk County police.
Brookhaven acting supervisor Kathleen Walsh signed a new order extending the mandatory evacuation for the town's portion of Fire Island, and extended the state of emergency declared on Oct. 27.