Thousands of fish killed in apparent chlorine spill

Thousands of fish were killed this week in Mill Creek on the Chelsea/Revere border by what appears to be a chlorine spill, state environmental officials said.

Federal and state officials are attempting to get a handle on how many mummichog and silverside fish, eels, shrimp, and crabs were killed on Monday or Tuesday. On Tuesday, thousands of the dead organisms were discovered on the Mill Creek banks and floating in the water along a 1-mile swath of the waterway. But because the tide probably carried many of the fish out before they were all counted, officials have not been able to assess the kill.

The state `` considers this fish kill a severe incident, and we are working with local, state, and federal officials to try and trace the source of this spill and hold the responsible party accountable," said Arleen O'Donnell , acting commissioner of the Massachusetts Department of Environmental Protection.

The Mystic River Watershed Association , which alerted the public yesterday to the situation, said there was a strong stench of chlorine on the river when the fish kill was noticed. Officials are working to see whether there was an industrial leak or someone illegally dumped the chlorine into a storm drain that then flowed into the creek.

State officials tested the water for toxins and recorded 0.4 parts per million of chlorine, a minimum threshold for fish kills, according to state environmental officials. But the test was taken Tuesday afternoon after the tide had gone out and come back in, and officials suspect the actual chlorine content at the time of the fish kill was greater.

``We don't know where the chlorine came from," said Jenny Birnbaum, director of the Mystic River Watershed Association's Mystic Monitoring Network. ``But the more people pay attention to things like this, the less likely they will happen in the future."

State officials ask anyone with information about the kill to call 617-556-1000 .