On Saturday, a short stretch of the Hillsborough River in front of Curtis Hixon Park in downtown Tampa is "going green."
Former Mayor Bob Buckhorn started the tradition in 2012.
Every year since — except for one during the pandemic — the city has transformed about a half-mile stretch of the river into a "River o’ Green."
The city uses a powder chemical called Bright Dyes, supplied by the Ohio-based company Kingscote Chemicals.
A safety data sheet on the chemical says it is "not hazardous according to (the Occupational Safety and Health Administration)" — the federal organization that ensures safe working conditions. The dye also contains no regulated pollutants outlined in the Clean Water Act.
However, as an environmental precaution, the document says to "prevent (the chemical) from entering into soil, ditches, sewers, waterways and/or groundwater."
A petition started a year ago by fishing guide Dustin Pack asking the city to stop dyeing the river green references that precaution.
"I started this petition with the hope that the City of Tampa will recognize that Tampa Residents and visitors can celebrate St. Patrick’s Day without changing the color of an entire river," Pack wrote in the petition.
But Tampa Water Production Manager John Ring said the powder mixture used is safe for the environment and wildlife.
“I understand (anglers) would have a concern," he said. "That is their livelihood and that is their backyard and we would not be putting it at risk.”
Ring said the precaution in the safety data sheet is geared more toward a bulk spill of the concentrated dye — but the city mixes water with the dye to lower the concentration.
“It is safe. But when you look at the chemical datasheet, I think you could walk away from that thinking this is a dangerous product and it is not,” he said.
When the city began dyeing the river, about 150 pounds of the product was used. Instead of mixing it, the powder was sprinkled directly into the river.
Now, about 250 pounds of the powder is mixed with water offsite. The approximately 280-gallon mixture is then transported to the boats at the park.
The liquid mixture is then put on the surface of the river by boats and reapplied throughout the event.
The dye starts breaking down two to three days after application, but Ring said that is dependent on weather and tidal conditions.
Chris Pratt is the senior environment manager at the Environmental Protection Commission of Hillsborough County in the water division.
He said the EPC is "neutral" towards the river dyeing. He said where the dye is applied to the river is influenced by tides and washes out regularly — which is why the dye must be continuously applied during the event.
"(Tampa has) been doing this event for a long time and we haven't seen any negative effects in their reports of fish kills, animals, or habitats in distress after the event," Pratt said. "So that's why we're comfortable with the application on the dye."
Pratt said the EPC is more concerned with things entering the river daily — trash and oil from cars. But still, he understands the anglers' concerns because the "Hillsborough River is a gem."
"It's a short time, short duration, one time a year event," he said. "And that's why we really don't have any continuing concerns about this particular thing."
River o' Green runs from 11 a.m. to 6 p.m. this Saturday at Curtis Hixon Park.
