A top executive with the U.S. Environmental Protection Agency says the agency is following widely accepted protocols when handling the Flint water crisis.

MLIVE reports that Christopher Korleski, director of EPA’s Water Division, also told Flint’s City Administrator, Sylvester Jones, that the agency is not “experimenting” with its water treatment advice.

“This is not ‘experimenting’ in Flint,” Korleski’s Mar. 27 letter says. “The ‘experiment’ would be taking actions outside these norms.”

The letter detailed the agency’s recommendations for corrosion control, increasing chlorine residual levels and correcting the low pH levels in residents’ drinking water.

Jones reportedly has a history of vocalizing concerns about chemicals being added to the city’s water supply.

In a letter written in November, acting EPA Regional Administrator Robert Kaplan told Mayor Karen Weaver that Jones was concerned “about chemicals being added to the Flint water for the purpose of disinfection and corrosion control.”

Jones also reportedly said there are “considerable questions around the … water at the tap” in a meeting of the Flint Water Interagency Coordinating Committee last month.

Korleski’s letter this week says the EPA’s recommendations on water treatment, which have not changed in 10 months, are “based on the need to maintain consistent water quality in the distribution system …”

According to Weaver, city officials have voiced concerns because “we don’t want to repeat the mistakes that lead to this water crisis.”