BALTIMORE — A putrid, fluorescent green algae bloom has engulfed Baltimore's Inner Harbor, creating a nauseating stench that visitors can smell blocks away and leaving locals concerned about the worst outbreak in years.
The so-called "pistachio tide" has transformed the harbor's waters into what one observer described as looking "radioactive" with its bright fluorescent green color. The smell has been compared to everything from sulfur and chemicals to "burning rubber mixed with sea and death."
"The smell ranges all the time. It ranges from a sulfur type of smell, a very chemical smell," one person said.
The odor has become so overwhelming that it's making people physically ill.
WATCH: Foul-smelling 'pistachio tide' takes over Baltimore's Inner Harbor
"It has gotten to that point where it smells so incredibly awful where it is making people sick and it's making people nauseous," a local resident said.
Naomi Evans, visiting from Virginia with her husband, noticed the stench immediately after leaving their hotel.
"A few blocks away you could smell it and you can just smell it all around," Evans said.
Roman Giordiano, who has worked on the water for four years, says this year's pistachio tide is unprecedented in both duration and scope.
"This did not start yesterday. I think almost two months ago it started. It started off very slow and it's just kind of branched out towards the Key Bridge and it's gotten a lot larger over time," Giordiano said.
"This is the most I've seen it branch out and the longest that I've seen it last, and it's concerning. It's really concerning," Giordiano said.
The Maryland Department of the Environment explains that the smell and distinctive color are caused by bacteria that thrive in low-oxygen water conditions. These bacteria are fed by nutrients from stormwater runoff.
"Nutrient inputs come from a wide variety of sources, pet waste, there's failing septic systems, agriculture runoff from construction projects, soil loss, it's a wide variety of sources," an MDE representative said.
Unfortunately for Baltimore residents and visitors, the department warns that warm weather will likely keep the malodorous conditions around longer.
"It's gonna take a significant weather event, a significant rainfall and cool weather to sort of change the conditions," the MDE representative said.
The Maryland Department of the Environment is asking the public to report any fish die-offs immediately to the state.
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