Flint, Michigan (CNN) Residents of Flint, Michigan, began getting gravely ill and in some cases dying in summer 2014 in one of the worst outbreaks of Legionnaires' disease in U.S. history, and a county health director says attempts to find the source were hampered when the state wouldn't request federal assistance.

Genesee County Health director Jim Henry tells CNN in an exclusive interview he believes deaths could have been prevented, but the health department could not get help from the state of Michigan or the Centers for Disease Control to find the source. Eventually, 87 people got Legionnaire's and nine died.

Henry, who was a supervisor at the time of the outbreak, says state officials purposely kept the CDC away once the county wanted to look at the highly corrosive Flint River as the Legionnaire's uptick began. The state had decided to switch the water supply source to the Flint River, and soon brown water began flowing from taps in the city.

"We were suspecting the city of Flint water supply," Henry says. "That was the big red flag. Stickin' out like a sore thumb. We needed to check the water in that system."

So, Henry says, his county reached out to the CDC, the federal agency tasked with investigating outbreaks.

"We expected that we'd have a team of people that would help us identify the source of this bacteria, the source of this illness to ... to stop it," he says.

But that never happened. The CDC never showed up and Henry says Michigan state officials purposely kept them away.

"Frustration is an understatement," Henry says. "You could see that it was an intentional, deliberate method to prevent us from doing our job."

According to CDC protocol, a state must "invite" the CDC to investigate an outbreak. And Michigan did not do that.

"The state stopped our investigation by prohibiting us to communicate," Henry alleges. "They prohibited communication between the Centers for Disease Control and Genesee County Health Department. They prevented that team to come here and help us find the source."

Michigan state officials did provide assistance, but never found the cause of the outbreak. The state wouldn't agree to an interview, saying, "We were able to meet the epidemiological case investigation need in the county. CDC was a part of these conversations as they were involved in many aspects of the investigations."

But the CDC says it "felt that a comprehensive investigation was warranted and offered to further assist Michigan."

"In this case, Michigan felt that they had the skills and resources needed to perform the investigation themselves," the CDC says.

Henry says the county tried to get to the bottom of it as the death toll rose, but alleges, "There was no consideration for the families."

"They refer to 'em as cases. They refer to 'em as numbers," he says, growing upset and angry. "They refer to 'em as just -- just a number. And these are families."

The human toll of the decisions

Troy Kidd's 2-year-old daughter will never know her grandmother Debra.

"I got a lot of great memories with my grandmas, my grandparents," Kidd says, growing upset. "She's never gonna have that opportunity."

His mother, Debra, was hospitalized in Flint with one of the worst migraines she ever had in July 2015, he says. Doctors gave her medicine and discharged her within a few hours. But within a couple of days her fever jumped to 104 or 105 degrees, her son says. She was sent to another hospital, her oxygen levels dropped, and doctors told Kidd his mother's lungs "weren't functioning on their own." She was diagnosed with Legionnaires' disease and later died.

Kidd is suing the state and McLaren Flint hospital, part of a class-action lawsuit.

The hospital says it began aggressively testing its water supply after noticing an uptick in Legionnaires' cases at the hospital, and countywide, after the water supply switch. Early test results indicated the presence of a low level of legionella. It also said it installed a secondary water disinfectant system throughout the entire facility at a cost of $300,000 and also installed lead filters on water and ice machines.

Kidd still believes that short visit to the hospital is when his mom contracted Legionnaires'; the governor announced low levels of the disease bacteria was discovered in the hospital's water system.

Dr. Marc Edwards, a Virginia Tech researcher who studied Flint water and found high levels of lead, said it would be almost impossible to make a definitive link between the water source and Legionnaires' disease. To do so, he said, would require matching the strain of Legionnaires' in someone's body to the strain in the water.

"We'll never know for sure, but we did find very high levels in the time period when they were on the Flint River water."

Edwards said this might be the first case of Legionnaires' associated with lack of corrosion control. Edwards says without those controls, the corrosive water would eat away at iron pipes and affect chlorine levels and give legionella bacteria a chance to flourish.

Kidd will never know the source of the Legionnaires' that killed his mother, but every time he hears it brought up, he can't help but wonder about the timing and possibility.

"I hope my mom didn't die ... because they didn't want to put something in the water to stop corroding pipes," he says.

'They cannot treat people this way'

Connie Taylor, 63, says she suffers every day because of the choices that were not made by officials. Taylor believes she, too, got Legionnaires' after a hospitalization. Now she is on kidney dialysis several days a week and waiting to see if her daughter is a match so she can get a kidney transplant.

Taylor was hospitalized with stomach pain for seven days; she believes it was E. coli. A week later she drove herself to the hospital when she had pain in her chest. Doctors told her she had hospital-induced pneumonia, likely from her last hospitalization. She was moved to intensive care.

"I wasn't getting any better," she says. "They called my daughters out to the hallway one day and told them that if I didn't improve my breathing, they was gonna put me on the respirator and they did not know how long I would last."

She remembers crying when they told her that her kidneys were beginning to fail. After more than two weeks in the hospital she was released to a nursing home.

"I couldn't stand up. I couldn't walk," she says. "Because all the time I had been in the hospital, I didn't have any strength."

Taylor says she never thought she had Legionnaires' until Gov. Rick Snyder announced the spike in cases and she began looking up symptoms. When she had a follow-up appointment with her doctor, she says he told her to get her records because he thought she might have Legionnaires.'

"They cannot treat people this way," she says of state and hospital officials. "I feel like I need to be compensated for the suffering I went through."

No matter what the outcome, Taylor says she won't be able to trust officials; Taylor will use as much bottled water as possible and is debating moving from Flint, her home since she was 11 years old. It's not the city Taylor remembers growing up in anymore.

"[Even] if they told me I could drink water [and] it was nice and pure and nothing wrong with it, I still wouldn't drink the water," she says.