Ep 12 Flint Water Crisis

Engineering News - Self Repairing Concrete


Engineering Failure - Flint Water Crisis


Map of Flint, the Flint River and the Detroit River

Source - Google Maps

Residential Water Lead Levels in Flint

Sources:

Engineering News:

Self Repairing Concrete - https://techxplore.com/news/2021-01-tunnels-bridges.html

Flint Water Crisis


Episode Summary

Hi and welcome to Failurology; a podcast about engineering failures. I’m your host, Nicole, and I’m from Calgary, Alberta.

A couple housekeeping items up front. I will be doing a Q&A bonus episode in a few weeks. If there is anything you want to ask me about me, my job as a mechanical engineering consultant, the podcast, or about engineering in general; please send them to @failurology on twitter or email them thefailurologypodcast@gmail.com.

Second item, I'm very excited to announce that the podcast is now available on youtube. So, if youtube is your preferred method to consume media, please head on over and check it out. My channel is called Failurology. There’s a link to it in the show notes for this episode.

This week’s engineering failure is the Flint Water Crisis. This one hits home especially hard for me because while I’m from Calgary, I wasn’t born here. I was born outside of Windsor Ontario, which is just a short drive and a border crossing away from Flint. I moved to Calgary in 2008, after graduating from post-secondary.

Detroit, coined the motor city, was an automotive hub for decades, ever since Henry Ford started the Ford Motor Company in the early 1900s. Manufacturing kept the economy, on both sides of the border, spinning for decades. And not just the employees at the factories themselves, there were several tool and die shops, suppliers, transportation, and many more industries feeding those factories. You could even argue that all of those people in the roles I just mentioned spent their money on food, housing, entertainment, and the like that spread out like a spider web and integrated into the fabric of the entire economy of the area.

When those factories close, it impacts everyone. Now to be fair, those companies are well within their legal right to relocate. But that doesn’t mean it isn’t going to negatively impact those left behind. I witnessed the first hand in Windsor, and if I’m being completely honest, it’s one of the reasons I left. I strongly believe in economic diversification. You can’t put all of your lemons in one basket, because if, or when in most cases, the bottom drops out, now you have no lemons. How are you supposed to make lemonade without any lemons? Alberta even has this problem to an extent; our current administration is very focused on the oil and gas sector. I’m not saying we walk away from oil and gas, but the world is changing and we need to stay ahead of the curve. There are other industries, such as tech, that require similar skill sets to oil and gas that we could focus some of our energy on.

But back to Flint. By 2014, they were struggling economically. At its peak population in 1960, Flint had almost 200,000 people. This is when a lot of the original service pipe infrastructure would have been installed. Today, there are under 100,000 people. And that population has shrunk almost 25% since 2000.

The reduced population not only impacted the tax base, and revenue generated for public programs, it also created dead legs of piping, or sections of pipe with no flow. With limited income, the City of Flint went into a state of financial emergency and a series of very poor decisions were made which ultimately led to the water crisis that started in 2014 and from what I can see, is still going on today.

How many times a day do you use the water taps in your house? We drink from it, we cook with it, we bathe in it. In Canada, most of us have been spoiled and blindly trust that the tap water won’t hurt us or kill us. I wish I could say that people worldwide have access to clean, safe tap water; but that’s just not the case. In Canada and the United States, there are still several communities either don’t have access to flowing water, or the water they do have is harmful in some way or another. To know the water is bad is one thing, but to find out after you’ve been drinking it for months that it’s toxic? Not even when just ingested, but also even when bathing in it? I can’t even imagine. This is the nightmare that Flint residents have been living with.

Then to make matters worse, once the cat was out of the bag, the officials in charge didn’t really step up and take responsibility. They fought with the residents of Flint for months before making any kind of correction. While the water source has been corrected, a lot more pipes still need to be replaced and that process is still ongoing.

And let’s not forget that health care is not a right, but a privilege in the United States. Many Americans are either not insured or underinsured, meaning the financial burden of the health effects from this problem that they didn’t want or didn’t cause, will land on the residents of Flint themselves.

Since the politics of Flint are an integral part of the story, I am going to touch on that. But this is not a political podcast, so I will try to keep it to the science of how and why the water source and piping impacted the people of Flint. But talking about Flint, without pointing out the environmental racism, would be a disservice to the people of Flint. If Flint had been rich or mostly white, would they have gone as long without clean drinking water? Would they even have had toxic drinking water in the first place? I don’t believe so. One thing has been clear from all of the things I’ve read about the Flint water crisis, those at the top, didn’t give a damn about the people of Flint. Not even when they started speaking up and had the water tested. Nothing really started to change until word got out on what was really going on and the rest of the world was watching. And it’s still not even over.

I’m going to take a deep dive into what happened in Flint, but first, the news.


This week in engineering news; buildings, tunnels and bridges could repair themselves by imitating the automatic healing properties of the human body. Cracks in structures are very common. And as cracks form due to movement, vibration or general wear, they provide a path for liquids and gases to enter the structure and impact durability of the concrete or stone itself but also the rebar as well. In cold climates, any water that enters can freeze during the winter and cause even more damage. Repair to ageing infrastructure takes a huge portion of annual maintenance budgets. And replacement costs are even higher.

Engineers and researchers have been working with bacteria to develop ways to repair damage to stone, masonry and concrete. Previously, other groups have demonstrated that it’s possible to create self healing concrete by including bacterial spores within tiny capsules in the initial concrete mix. When a crack forms, the capsule ruptures and the bacteria multiply, producing calcium carbonate; hardening and sealing the crack. I’ve often seen similar products used on foundation concrete to prevent groundwater from impacting the integrity of the structure.

But what about existing structures or natural stone?

The GEOHEAL project at Cardiff University in Wales UK has developed a technique to spray or brush existing structures with a liquid containing naturally occurring soil bacteria, working its way into the rock and eventually healing damage as it occurs. Additional calcium is added to the liquid so that the bacteria doesn’t feed off the calcium in the stone and degrade it further.

The bacteria have also been used to develop a self-healing mortar to hold stones and brick together. When cracks form, the nutrients are exposed to the bacteria, feeding it, multiplying it, repairing the cracks.

A two year test project found that the bacteria could improve the microstructure of the masonry, didn’t change the appearance and didn’t impact the breathability of the stone.

The applications for these solutions are vast for existing, aging structures. The construction industry is responsible for about 11% of greenhouse gas emissions worldwide. By helping this infrastructure to last longer, the self healing materials can reduce those emissions.

If you want to read more on self healing structures, check out the link on the web page for this episode.


Now on to this week’s engineering failure; the Flint Water Crisis. After switching the City of Flint’s water supply from the Detroit River to the Flint River in April 2014, over 10,000 children were exposed to lead in their drinking water, at least 12 people died of Legionnaires’ disease and an estimated several hundred pregnancies ended in stillbirth.

Before I get into the hows and whys of the Flint Water Crisis, there are some things you need to know first.

  • Most people say that the state of Michigan looks like a mitten, with the thumb on the right or east side. Detroit is roughly at the spot where your second knuckle, the one closest to your palm, would be; bordered with Ontario. And Flint is about 100km west of the first knuckle, the one closest to your thumbnail.

  • Water flows south from Lake Huron, between the US and Canada, through the St Clair River, into Lake St Clair, which is not one of the five great lakes. From there it flows through the Detroit River and into Lake Erie on its way to the Atlantic Ocean.

  • That’s the basic geography of the area. I also want to explain more about lead poisoning and Legionnaires disease. I am deliberately doing this upfront, so that when you are listening to the timeline and events that transpired in Flint, you have an understanding of what that meant exactly for the people impacted. For what it’s worth, biology is not my strong science, but I’m only doing an overview.

  • Lead poisoning

    • Lead poisoning is a type of metal poisoning caused by lead in the body due to direct contact with the mouth, nose, eyes and through breaks in the skin

    • The brain is most sensitive to lead poisoning, but it can also impact the kidneys and blood, which can be reversible in some cases. The effects on the central nervous system are not, especially in children. Even once the lead exposure is removed

    • Majority of absorbed lead is stored in the bones and teeth, up to 94% in adults and 70% in children. The half-life of lead in bone is 20-30 years. It then leeches into the bloodstream long after the initial exposure.

    • Lead also mimics other heavy metals and binds to receptors in the body, preventing the body from absorbing other nutrients like iron, calcium and zinc.

    • Symptoms include abdominal pain, constipation, headaches, irritability, memory problems, kidney damage, high blood pressure, infertility, and tingling of the hands and feet. Lead poisoning can cause intellectual disability, behavioural problems, and in severe cases, anemia, seizures, coma, or death may occur. Some effects are permanent.

    • There are multiple causes of lead poisoning, for the purpose of this podcast; I am going to focus on lead poisoning from a water source.

    • Acidic water breaks down the lead in the pipes more readily, but chemicals, including corrosion inhibitors can be added to increase pH and reduce the corrosivity of the water supply piping. That said, chemical treatment is only a band aid solution, the only permanent fix is to replace the lead piping completely

  • legionnaires disease

    • Legionnaires disease is an atypical pneumonia caused by Legionella bacteria. The bacteria is found in freshwater and contaminates hot water tanks, hot tubs, and cooling towers of large air conditioners

    • It is usually spread by breathing in mist containing bacteria, or when contaminated water is aspirated. Transmission from person to person is rare

    • Symptoms include cough, shortness of breath, high fever, muscle pains, headaches, nausea, vomiting, and diarrhea; beginning 2-10 days after exposure

    • There is a 10% risk of death, resulting in 13,000 deaths per year. Old age, a history of smoking, chronic lung disease, and poor immune function are risk factors

    • Antibiotics are used to treat Legionnaires disease, but there is no vaccine available

    • The bacteria thrives between 25-45C, with an optimum temperature of 35C. Temperatures above 60C kill the bacteria. This is why domestic or potable hot water systems are maintained at 60 C and continuously circulating to prevent stagnant warm water from allowing the bacteria to thrive. This is an integral part of plumbing design, as well as water distribution. The hot water tank output temperature is something I check on every project before occupancy.

    • This is also why it’s very important that dead legs or pipes that do not connect to anything and receive no flow, something which was common in Flint as the population reduced, are isolated and or removed from the system, to prevent legionella bacteria growth and infiltration into the water supply.

  • Some of the water service piping was installed in Flint between 1901 and 1920. Due to cost and ease of install, the pipes were constructed of lead. Lead can leach into the water if the water is acidic or if certain contaminants are present. There are an estimated 43,000 service pipes in the City, 3,500 lead, 9,000 galvanized, and 9,000 unknown. Although this is just an estimate, the records are spotty at best.

  • Until 1967, Flint received its water from the Flint River. A river which drains over 3000km2 from seven Michigan counties surrounding Flint. The river has suffered from decades of industrial pollution, although it has improved since the 50s and 60s. In one of the documentaries I watched, it said that some factories pulled water out of the river for their plant and dumped it back in, untreated. The river was also impacted by road salt, fertilizer, sewage and the like. Killing all the fish by the 1940

  • From 1967 to 2013, the City of Flint received its drinking water from Detroit Water, which comes from Lake Huron. This water has been treated well enough that it meets the lead levels considered safe by the state and federal environmental protection agencies. That said, no blood-lead level is really safe. Children under the age of 5, especially infants and unborn children bear the greatest risk.

  • In 2011, the City of Flint declared a state of financial emergency.

  • A lot of this was caused by a significant reduction in manufacturing, impacting the City’s economy and tax base as people moved away. Some of the manufacturing changes are as follows:

    • The Buick assembly, engine, and powertrain plants closed in 2010.

    • A GM spark plug, filter and instrumentation plant closed in 2013.

    • All but one building of the Chevrolet tool and die complex have closed.

    • Fisher Body Flint Plants #1 and #2 closed in 1987 and 1970 respectively.

    • The GM Grand Blanc Weld Tool plant closed in 2013

    • The Coldwater road plant closed in 1998.

    • As more and more plants closed, the population started to decrease, resulting in lots of stagnant water pipes.

  • Declaring a state of financial emergency allowed the Governor at the time, Rick Snyder, to appoint an Emergency Manager, who effectively takes the place of the mayor, and makes all major decisions for the City, without input from the municipality or people. There were four emergency managers from 2011 to 2015, the first of which was Michael Brown.

  • In March of 2012, officials announced a plan to stop using water from Detroit and start using water from the Flint River as a cost saving measure.

  • It was estimated that it would cost 60million to upgrade the existing Flint water treatment plant, but they only spent 8-9million. On top of that, they were operating on a consolidated time frame. They only had one year from the announcement until the Detroit Water contract expired. Water treatment employees told them that wouldn’t be enough time. One employee, Michael Glasgow, sent an email stating the treatment plant was not going to be prepared.

    • Honestly, I come across stuff like this a lot. I don’t know if I’ve ever had a project be completed on time. And not necessarily because the contractor delayed on purpose. Most of the time, I look at the schedule at the start of the job and it’s just too aggressive. I’m not rooting against them; the schedules are just too tight to stick to. And I honestly don’t know why they agreed to, in the first place. I personally, would rather see a realistic schedule that is kept, than an unrealistic one with a bunch of delay claims. The delays take up a lot of time to discuss and rearrange things ; time that people don’t really have. That said as a consultant, the schedule doesn’t really matter to me too much one way or another. I certainly don’t get in the way of it, but if the job is late and I have to push my final review back, then I push it back. For me, the site’s ready when it's ready.


  • By April 2014, the water source switch from Detroit Water to the Flint River was completed. And the water crisis begins.

  • As I mentioned earlier, acidic water increases corrosion and the leaching of lead from the piping infrastructure into the water supply.

  • There are five key warning signs about the possibility of corrosion, they are as follows.

    • Process changes that result in pH or alkalinity changes

    • Process changes that affect the CSMR chlorine to sulfate mass ratio changes

    • Change in coagulant

    • Introduction of a new acid to the process

    • Introduction of a new base

  • All were present in Flint, and all were ignored. In addition, measurements for bromate were not properly taken for much of the Flint plant’s operation and the required testing for E Coli and Cryptosporidium were not completed.

  • The existing lead pipe infrastructure was also a major oversight. It can represent as much as 75% of the observed lead concentration in tap water.

  • From June 2014 through November 2015, there was an outbreak of Legionnaires disease. The outbreak wasn’t announced until January 2016. Even though a boil water advisory was in place for a week in August 2014 and then again in September.

  • The water was so bad, that by October 2014, GM’s Flint assembly plant stopped using the Flint tap water because high levels of chlorine were corroding engine parts. I’m going to say that again. The GM assembly plant stopped using Flint tap water because it was corroding engine parts. Engine parts are made of metal, what do you think this water was doing to humans?!?

  • In January 2015, Flint residents complained about the water, even bringing bottles of discolored tap water to community meetings. There’s a picture of the tap water on the episode webpage if you want to check it out.

  • In February, the EPA detected lead levels SEVEN TIMES the acceptable limit in a Flint home.

  • In March, the Flint City council voted to return to Detroit water. But the Emergency Manager, who was now Jerry Ambrose, overruled and blocked the vote. Leaving Flint on the Flint River water system.

  • By September 2015, Virginia Tech’s water study found that 40% of Flint homes had elevated levels of lead.

  • The Michigan Department of Environmental Quality tried to downplay all of the studies, which were essentially the facts about the state of the drinking water in Flint, while at the same time stating that Flint needs to upgrade its infrastructure. It’s always really interesting to me when people, especially government officials, ignore science. Maybe it’s because I consider myself a woman of science, but whenever I want to know something, science is where I look first.

  • A Hurley Medical Centre pediatrician released a study showing an increased number of children with elevated lead levels in their blood following the switch to the Flint River water source.

  • In October 2015, Governor Snyder signed a 9.35 million dollar bill to reconnect to the Detroit water system. The switch was made the next day. The initial switch was made in April 2014, so the city of Flint was on the contaminated drinking water source for 18 months. 18 months too long if you ask me.

  • Governor Snyder apologized publicly to Flint on December 30th, 2015 and again January 6th, 2016.

  • On January 16th, 2016 President Obama declared a state of emergency in Flint and authorized 5 million in aid, the National Guard was brought in to help distribute water, and a water bill subsidy was put in place. Yes, the residents of Flint not only paid for the contaminated drinking water, but they were still paying for it, even after they knew it was toxic.

  • In February 2016, the water service pipes were identified as the main source of lead in the water. But the municipal records were outdated so they didn’t know exactly the full extent of the lines or their locations.

  • Criminal charges were filed starting in April 2016, fifteen people were charged. But only one was found guilty.

  • In September 2016, Flint used a machine learning model, using data about the home and neighborhood, to prioritize service line replacements. The model was developed by two University of Michigan professors and it had an accuracy rating of about 80%. Go Blue.

  • In early 2017, the yearlong water bill subsidy ended.

    • Flint had the highest water rate in America for water they couldn’t use.

  • In March 2017, a federal judge approved $97 million in funding for examination and replacement of lead water service piping to 18,000 Flint homes, to be completed in a three-year time frame, with the first 6,000 being completed by end of 2017.

  • There are two other American communities that have successfully replaced all of their lead pipes;

    • Lansing MI upgraded over 10 years starting in 2004. They combined this project with an already planned sewer overflow replacement project. They also designed a new process where the new pipes would push out the old lead pipes, eliminating the need to dig trenches.

    • In Madison Wisconsin, the city only owned pipes in the streets. But they passed an ordinance, requiring everyone to replace the lead pipes on their property and reimbursed the residents half the cost.

  • In April 2017, Mayor Weaver and Governor Snyder decide to remain with Detroit Water

  • In May 2017, 8,000 residents received notice that their water will be turned off due to lack of payment. The City even went so far as to file liens and take homes for outstanding water bills.

  • By the end of 2017, the City of Flint had signed a 30 year deal with Detroit Water. And water sampling from some parts of Flint showed a reduction in lead. Although in early 2018, a spike in samples from Flint elementary schools tested above the lead threshold.

  • A study that was published in 2018 found that low levels of chlorine were likely the cause of the Legionnaires outbreak. Since chlorine reacts with heavy metals like lead and iron, they likely reduced the chlorine levels when the water supply came into contact with the lead piping. Meaning that there could have been adequate chlorine added at the treatment plant, but the concentration was reduced after passing through lead pipes. There was also no corrosion inhibitor added to the water to prevent the lead and iron from leaching into the water supply.

  • A few things happened in April 2018.

    • The state of Michigan ended the distribution of free bottled water, even though not all of the lead pipes had been replaced. Remember, people are using bottled water for drinking, cooking, bathing, everything. An average Flint family uses over 150 bottles of water PER DAY. That’s 150 bottles that they now have to procure for themselves every day.

    • a federal judge approved a $4.1 million settlement to test Flint children for lead poisoning

      • 30,000 kids need to be screened for lead poisoning, and this is ongoing. But then what?!? The one’s with elevated blood-lead levels will face a lifetime of health issues ranging from learning difficulties to seizures.

    • and the EPA approved a $1.6 million grant for Virginia tech to test drinking water nationwide, starting in Michigan and Louisiana and branching out from there.

  • May 2018, Nestle donates 1.6 million bottles of water. Not to take away from this kindness, but this is a little ironic considering Nestle has been in the news over the last few years for exploiting the environment and misleading consumers about their water quality, specifically its high levels of micro plastics. Some jurisdictions have even filed class action lawsuits against Nestle. In fact, in 2017, while Flint was battling the water crisis, two hours away, Nestle was pumping 100,000 times the average Michigan person’s water usage into plastic bottles. Nestle only pays $200 per year to use this resource.

  • June 2018, Michigan enacts the strictest lead limit in the US, stricter than the federal limits, expected to be achieved by 2025.

  • By Mid-2018, 420 filtered water samples from Flint schools show lead ranges below the acceptable limits.

  • In January 2019, Michigan’s new governor, Gretchen Whitmer, signed an executive order requiring state employees to immediately report any threats to public health and safety.

  • By February 2020, over 25,000 water service pipes have been excavated, resulting in replacement of almost 10,000 lead pipes and over 15,000 copper pipes.

  • Earlier this year, in January 2021, former Governor Rick Snyder and eight other former Michigan officials were charged in connection with the Flint Water Crisis. This court case is still ongoing and I will be watching closely.

  • One important thing I want to note is that Flint residents could not trust the testing data from government officials and many had independent testing done. I’m not really sure if the governments testing data was blatantly false, or just incompetent. But they certainly had a motive to cover up the issues.

  • Engineering firms were engaged by officials to review and comment on various parts of the Flint water system. I want to touch on two that I found most concerning.

  • LAN (Lockwood, Andrews, and Newman Inc) flagged the concern for the possibility of corrosion to the City of Flint, but when the City decided not to do anything about it, LAN dropped it. This goes against the US National Society of Professional Engineer’s Code of Ethics to protect and serve the public above all else. Canada has a similar code of engineering ethics and public safety is top priority here as well. I certainly understand that engineers are hired to complete tasks within an outlined scope of work. But when factors, even outside of that scope, impact public health, engineers need to be whistleblowers to protect people. That is really our primary objective.

  • And then there was Veolia North America, who was contracted to assess the water quality in Flint. Their report suggests that Flint should flush their water at the hydrants, which is only a temporary, band aid solution and doesn’t even address the root cause. Remember a couple episodes ago when I talked about problem solving. Veolia didn’t look into the root cause of the problem; they only treated a symptom. Not to mention it was an extremely short-sighted option to appease the complaints. What are you going to flush your lines every month, every week…? I mean come on guys, that isn’t going to fly long term.

    • They also state that because the previous reports on the water meet the state and federal standards, the water is safe to drink. Ok, I get it, you are only as good as the information you are given. And it’s possible that they were given incorrect, or outdated, or even doctored data to show the water was fine. But by 2015, when their report was published, people were aware there was an issue with the water, wouldn’t you have ordered separate third party testing? I would have at least asked. Actually I probably would have gotten my own sample tested just out of pure curiosity. If you’re going to put a stamp on something telling people it’s safe, you’d better be sure it’s safe, at least to the best of your ability.

    • Unsurprisingly, Veolia argues they hold no responsibility in the Flint water crisis because they stuck with exactly what they were contracted to do.

    • To me, engineering is problem solving. It’s figuring out how to do something that hasn’t been done before. Even when comparing similar projects, each design is still custom to the building. I don’t mean to gatekeeper here, but problem solving is an integral part of engineering, and if it's not your cup of tea, maybe engineering isn’t for you, or at least stay out of the technical part of it. Again, not trying to dissuade anyone from engineering or tell someone they shouldn’t do it, but you need to understand the importance of being able to effectively solve problems if you want to be an valuable engineer.

  • Does Flint have clean drinking water now? Well, their source is reputable, but no one trusts the water quality until all of the lead pipes are replaced.

  • Ok let’s do the math here for a second. I love math. And while it’s not really viewed as artistic, I always think that it paints a really nice picture of reality.

  • The shortcuts in the water treatment when they switched to the Flint River were estimated to cost 60 million, but they spent 8 or 9 million; a savings of 51 million. I read that they saved $141/day by not adding a corrosion inhibitor to the water, so that’s about $50,000 per year. And the switch to the Flint River water supply was expected to save 5 million over 2 years. Even though the switch only lasted 18 months, I’ll give them their 5 million. So in total, they saved just over 56 million dollars by making the switch,

  • Since the water crisis, the state and federal governments have either paid or been ordered to pay over 700 million dollars to the City and victims for piping repairs, lead poison testing, health care, and the like. And that’s in addition to the costs of bottled water, the National Guard, administration time, both at the municipal, state and federal levels, and now the court and lawyer costs for the pending charges.

  • When you do the math, no one comes out ahead here. In fact, they are all much, much further behind than if they hadn’t made the switch in the first place. Too bad they hadn’t figured that out before they poisoned everyone in Flint.

  • If Flint had been rich or mostly white, do you think it would have been different? I do. Both Lansing Michigan and Madison Wisconsin, the two nearby cities who had their lead pipes replaced, were majority white communities. Environmental racism is defined as the disproportionate number of hazards, including toxic waste facilities, garbage dumps, or in this case, unsafe drinking water, burdening minority neighbourhoods, populated primarily by people of colour and members of low socioeconomic backgrounds, and impacting their quality of life. Just like the evacuation of New Orleans during Hurricane Katrina, or the lack of fire safety in the Grenfell Tower, the Flint water crisis is a very clear example of environmental racism. We’re all people. We all put our pants on one leg at a time, just like everyone else. And we need to do better at caring about others, regardless of what they look like or how much money they make.

  • So there you have it, the story of the Flint water crisis. How a struggling Michigan City was poisoned by their drinking water, starting in 2014. They aren’t alone in this. As tragic as this story is, hopefully it sheds light on drinking water quality issues in other areas and funding is made available to bring safe, affordable, drinking water to the masses.


Check out the podcast page, link in show notes, for photos and sources from this week’s episode. On this episode’s webpage, I have a map of Michigan showing Flint and Detroit, a map of Flint showing lead levels in residential households between 2016 and 2018, and two samples of water, one from Flint tap water and one from Detroit.

If you’re enjoying what you’re hearing, please rate, review and subscribe to failurology, so more people can find it. And if you want to chat with me, or send me questions for the Q&A episode, my twitter handle is @failurology or you can email me at thefailurologypodcast@gmail.com.

Thanks everyone for listening. And tune in next week to hear about the Chernobyl Disaster, considered the worse nuclear disaster in history. But more on that next week. Bye everyone, talk soon!