Updated 12/11/2017

The Alabama Department of Environmental Management discovered 3M Company was under reporting its discharge of potentially toxic chemicals into the Tennessee River before 3M notified the regulatory agency of the error, an ADEM spokeswoman said Friday.

The comment came in response to questions about whether ADEM had adequately reviewed 3M’s discharge reports for the chemicals, known as PFCs.

It also appeared to conflict with 3M’s earlier statements on how the error came to light, stated a media source.

In an April 20 letter, a 3M official advised ADEM that the company’s Decatur facility had under-reported its discharge of PFCs to the river by a factor of 1,000 for more than three years — from late 2012 to mid 2016 — and that it had discovered the discrepancy during an internal review.

3M reported to ADEM it had inadvertently reported its discharge monitoring reports in milligrams per liter instead of micrograms per liter due to a change in reporting metrics.