Big waves from Hurricane Erin bring the surfers to Nantasket Beach in Hull
There's a stinky situation in Gloucester, Massachusetts. Officials there say they've identified the source of a "strong odor" that smells like rotten eggs.
The city explained on Facebook on Wednesday that Heterosiphonia japonica, an invasive Japanese seaweed, is causing the smell in East Gloucester.
"When it washes ashore and decays, it releases a rotten egg-like odor that can seem concerning, but it's a natural process," the city said.
Noticing a strong smell around East Gloucester? 🌊 We’re aware of the strong odor in East Gloucester. The smell is...
Posted by City of Gloucester, MA on Wednesday, September 3, 2025The invasive seaweed arrived on the North Shore thanks to Hurricane Erin, which brought rough surf and big waves to the East Coast and forced several Massachusetts beaches to close for swimming because of dangerous rip currents.
"Last week's hurricane winds pushed large amounts of this seaweed onto our shores, and high tides carried it into the Good Harbor estuary," the city said. "Without another strong tide to pull it back out, it's sitting and decomposing, which is what you're smelling."
The red seaweed was first recorded on the East Coast in 2009 when it was collected off Rhode Island, according to the Smithsonian website. It spreads aggressively and has been connected to fish die-offs.
Residents on social media compared the smell to gas, and some complained of a sewage-like odor.
"It is a very nasty, pervasive stench," one commenter wrote. "This isn't your typical seaweed, low tide odor."
"It smells horrendous," another said. "I thought a large mammal died in the marsh."
The city said the smell should gradually go away as the seaweed breaks down.
Neal J. Riley is a digital producer for CBS Boston. He has been with WBZ-TV since 2014. His work has appeared in The Boston Globe and The San Francisco Chronicle. Neal is a graduate of Boston University.
