Initial Frequently Asked Questions (FAQ) regarding Legionella bacteria in present-day Flint

We have been getting questions from concerned parents about the Legionella announcement made earlier today and if there is a risk to taking showers.

1. Is it safe for me and my kids to shower in the water now?

A. We agree with DHHS that this problem, is probably behind us all, even it if was caused by the Flint River water. It is safe to shower now whether you are an adult or a child. When we say “safe,” we mean it is no riskier to shower in Flint now than in any other U.S. city.

2. Is this (was this) a risk only in high-rise buildings or plumbing systems in small homes can harbor Legionella pneumophila too?

A. During August of 2015 we focused our Legionella testing on residences and smaller buildings like McDonald’s throughout the city. Despite looking as hard as we could, we could find no trace of the Legionella bacterial strain that causes disease. So in homes and small buildings at least, based on our data, the risk of exposure was relatively low. We published those data on our website earlier in the year, and frankly, we were a little surprised there was not more Legionella.

However, just before the switch back to Detroit, we sampled larger buildings, and we found very high levels of the types of Legionella that cause disease. So we tend to feel, that the risk of exposure, was much higher in the bigger buildings.

3. The water has been “bleachy” in the last few days. Is that a risk?

A. This is actually a good sign that your risk of Legionella very low. The “bleach” or chlorine actually kills Legionella bateria.

Acknowledgements: Dr. Amy Pruden, Dr. Marc Edwards, Siddhartha Roy

Possible Links Between Flint River Water (Without Corrosion Control) and Higher Legionella Occurrence

A key hypothesis of our National Science Foundation RAPID grant is that the rapid corrosion of iron water mains in Flint would dramatically increase growth of Legionella in buildings. Mechanistically, higher rates of iron corrosion will produce: 1) higher iron in water, and 2) lower levels of free chlorine. Both of these factors were confirmed to be present in Flint during our field sampling, and have been shown to dramatically increase Legionella regrowth in our recently published laboratory research utilizing simulated distribution systems.1-5

Possible Legionella Link

Additional research is needed to examine the basis of this relationship.

  1. Masters, S., and M. Edwards. Increased Lead in Water Associated with Iron Corrosion. Environmental Engineering Science, (2015), 32 (5), 361-369.
  2. Masters, S.M., Wang, H., A. Pruden and M. Edwards. Redox Gradients in Distribution Systems Influence Water Quality, Corrosion, and Microbial Ecology. Water Research, (2015), DOI: 10.1016/j.watres.2014.09.048.
  3. Wang, H., Masters, S., Edwards, M.A., Falkinham, J.O. III, and A. Pruden. Effect of Disinfectant, Water Age, and Pipe Materials on Bacterial and Eukaryotic Community Structure in Drinking Water Biofilm. Environmental Science & Technology. dx.doi.org/10.1021/es402636u.
  4. Wang, H., S. Masters, Y Hong, J. Stallings, J.O. Falkingham, M. Edwards and A. Pruden. Effect of disinfectant, water age, and pipe material on occurrence and persistence of Legionella, mycobacteria, Pseudomonas aeruginosa, and two amoebas. Environmental Science & Technology 46 (21), 11566-11574 (2012).
  5. Wang, H., Masters, S.; Falkinham, J.O.; Edwards, M.; and A. Pruden. Distribution System Water Quality Affects Responses of Opportunistic Pathogen Gene Markers in Household Water Heaters. Environmental Science & Technology. (2015), DOI: 10.1021/acs.est.5boa.538

Author: Dr. Marc Edwards

Our friends at “WaterYouFightingFor?,” LeeAnne Walters and Melissa Mays win the “Hammer and Chisel Award” for their courage and heroism

Very well deserved!

These awards are created in conjunction with the upcoming release of Michael Moore’s new movie Where To Invade Next and honor “individuals who have, in their own unique and courageous way, made America a better place for all.”


We knew things were bad when water coming out of the kitchen taps in our homes in Flint, Michigan, looked like frying oil and smelled like an open sewer. We’re not water experts; we’re moms. But thanks to the blood, sweat, and tears of regular citizens, we learned our drinking water was contaminated with lead, a fact that our city and state governments refused to acknowledge for far too long.

Read the full story here: The Huffington Post

Del Toral’s Heroic Effort Was Ultimately Vetted in the Blood Lead of Flint’s Children

Excellent articles by Arthur Delaney at Huffington Post and Jim Lynch at the Detroit News shed light on delays in the Federal government’s response to the Flint water crisis.

EPA Region 5 Director Susan Hedman’s now explains that from April to November 2015, EPA was actively seeking a “legal opinion on whether the EPA could force action” at MDEQ to implement corrosion control. Hedman also correctly stated that:

Communication about lead in drinking water and the health impacts associated with that, that’s the role of DHHS, the county health department and the drinking water utility.

But what if MDEQ was refusing to do their job, as Hedman now acknowledges?

At what point did EPA notify the country health department, regarding its opinion that MDEQ was not following Federal law, so they could make an informed decision about communicating risks to the public about the health impacts of high lead in their drinking water?

More importantly, why should Flint’s children be allowed to drink lead contaminated water, unprotected by Federal law, while EPA and MDEQ spend months politely wrangling over jurisdiction, technicalities and legalities?

Our FOIA revealed that in early July, Hedman actually apologized to Flint Mayor Dayne Walling for Miguel Del Toral’s memo detailing the imminent peril of Flint’s children, and further said that:

When the report has been revised and fully vetted by EPA management, the findings and recommendations will be shared with the City and MDEQ and MDEQ will be responsible for following up with the City.

EPA also silenced Del Toral, and stood by as outsiders in communication with Hedman publicly discredited him. On September 8th 2015 Mayor Dayne Walling commented on the Del Toral letter:

“Walling said Weaver is making a mistake by citing a letter from “one individual staff person” who does not speak for U.S. EPA. “It’s dangerous for a candidate to make allegations that are not based on fact,” Walling said.

As late as September 29th 2015, MDEQ’s Brad Wurfel told NPR that:

“…the report was the work of a “rogue employee” and promised the final report — not yet released — would tell a much different story”

Regarding the above public attack by MDEQ Hedman stated to Huffpost that:

…. the Department of Environmental Quality apologized to him <Del Toral> for the “rogue” characterization. She emphasized that Del Toral is part of the team. “He is one of the top experts in the world on lead and copper in drinking water and a key member of EPA’s Flint Safe Drinking Water Task Force,”

Where and when did this MDEQ apology happen? Behind closed doors?

How did that private apology in late September, help shape public perceptions of the problem, or for that matter help the county health department or even Flint’s Mayor exercise their role to protect Flint’s children?

The disconnect between Hedman’s bureaucratic approach, and her agencies moral obligation to protect the public welfare, is perhaps best exemplified by events in early July immediately after Walling and Hedman first discussed the Del Toral memo. Specifically, Walling has been publicly excoriated for his July 9th appearance on local television drinking Flint water to demonstrate its complete safety.

Immediately after reading our e-mails FOIA’d between MDEQ and EPA, Walling <under>stated:

The federal EPA needed to be more aggressive with the DEQ…The emails show these concerns were being raised by experts, but they weren’t” being shared with the city.

When was Flint Mayor Dayne Walling finally informed by EPA that Del Toral and his memo were credible? In early October 2015. By that point, the validity of the Del Toral memo had been fully vetted in the rising blood lead of Flint’s children. EPA’s long awaited legal analysis was finally released in early November 2015-it essentially exonerated MDEQ.

Primary Author: Dr. Marc Edwards