SIMI VALLEY – A stretch of the Arroyo Simi turned bright green Monday afternoon when an unknown substance entered the waterway from an outflow under the First Street bridge.
The scenario brought hazardous materials teams and officials from multiple agencies, but authorities ultimately determined the product wasn’t harmful.
At around 2:25 p.m., a caller told emergency dispatchers that water in the wash below First Street and Los Angeles Avenue was fluorescent green, “like a river of radiator fluid,” said Capt. Stan Ziegler, of the Ventura County Fire Department.
Fire crews that initially arrived at the scene described seeing a “lime green” substance about a quarter mile down the arroyo.
The incident brought two of the fire department’s hazardous materials teams as well as staff from the county Environmental Health division, the city of Simi Valley and the state.
Dennis Rosenberg, a wildlife officer with the California Department of Fish and Wildlife, took photos of the outflow and inspected the arroyo, where the green product pooled and foamed up in areas downstream of the outflow.
By 5:45 p.m., officials had determined the product was not hazardous and was likely an automotive maintenance product, possibly a polish or wax. A car wash at the corner of First and Los Angeles, directly above the outflow, was shut down as crews investigated. Ziegler said it was not immediately clear whether the product had come from that facility.
With no public threat at stake, crews had turned their attention to cleanup efforts, Ziegler said.
As of 6 p.m., water downstream of the source remained bright green, with foam pooled over a still portion at the bottom of a small dam past Los Angeles Avenue. Egrets, geese, ducks, seagulls and other birds carried on avian activities in the colorful water.
On social media, photos of the bright green waterway prompted St. Patrick’s Day jokes in advance of the March 17 holiday.
“Looks like the leprechauns are a few days early,” wrote a Twitter used named melz.
The water flows from First Street toward Madera Road, where cleanup efforts could focus, officials said.