What caused the Middle Tyger River fish kill?

Published: Oct. 18, 2022 at 11:24 PM EDT
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LYMAN, S.C. (FOX Carolina) - We have now learned that a bleach overflow caused a fish kill in the Middle Tyger River.

Back in September, Brad Kiser reached out to us concerned dead fish floating on the surface of the river, right near the Middle Tyger Library, in Lyman. See the previous coverage.

The South Carolina Department of Health and Environmental Control (DHEC) investigated the fish kill on Sep. 17. DHEC determined that the fish kill was caused by an overflow of a sodium hypochlorite (bleach) tank at the Spartex-Jackson-Wellford-Duncan (SJWD) Water District facility.

DHEC says SJWD cleaned up the accident within five days of the report of the fish kill and monitored the river. Everything was cleaned to DHEC’s satisfaction. It plans to take no future action, at this time. And no additional fish kills have occurred since.

Kiser says he’s noticed the turnaround.

“I came out here the other the day. And I caught one little fish out here. So, there was, at least, some life back in the area,” said Kiser.

However, Kiser had some follow-up questions for officials.

“Roughly, how much [did] they suspect actually leaked out, and what went wrong?” Kiser said.

SJWD tells us it came down to mechanical and human error. A hypochlorite pump did not shut off after filling the day tank. A seal failure caused some bleach to leak into the basement of their building and, eventually, into the river.

“I’d be curious what the clean-up involved. I don’t know how you clean bleach out of a river,” said Kiser.

Here’s how: After meeting with DHEC, the water district says it started the standard, clean-up and investigation protocol. Staff used spill containment socks, sodium bisulfite—a solution harmless to most life forms that dissolves in water and can lower its pH, and water to rid the parking lot of any residual.

“As long as some actions are taken and something in place maybe to keep something like this from happening in the future,” Kiser said.

SJWD tells us the seal is being repaired, along with the addition of containment alarms.

A month later, we couldn’t find any more dead fish.

The South Carolina Department of Natural Resources says bleach is detrimental to aquatic life—like fish, amphibians, and crustaceans—and the insects they feed on. However, a fish kill like this is not long-lived. Streams can be diluted and recover with new water.

DNR’s investigation into the cost to the environment continues. Crews measure linear across the stream to get a sample.

DNR can’t be everywhere at once. You can report fish kills on the website here. The department credits Kiser for being the first to report the fish kill.

“It feels good. I’m a big fan of nature,” Kiser said, “So, anytime I can help out and prevent something there, I’m pretty happy about it.”

Kiser also brought up a recent, water discoloration issue.

Here is the statement from SJWD: