Transcript for On the Arizona frontlines, where first responders are battling a COVID-19 crisis
Reporter: All right, this is a call for an ill person. They're opening up the bay doors, and we're about to hop into one of those. Phoenix fire's engine 25 careens out into the merriville neighborhood. This is a possible covid call, everyone's got N95s on. About 50% of the calls this station does are covid calls. As covid rages across the country, Arizona one of the biggest hotspots. 34% of those tested in the state have the virus. Cases up over 850% since the state reopened on may 15. And tonight our "Nightline" team is with first responders, patients, test administrators and a doctor, all in the midst of an impossible situation. An explosion of cases amidst the collapse of the testing system. The firefighters we're with have been to this house before. 30-year-old construction worker Martine molina is helped out of the house. He's had a fever, splitting headaches. The timing couldn't be worse, though. His girlfriend had just given birth to their son three days and their 11 month old daughter has also been running a temperature. To be honest, I wasn't able to believe of this pandemic, but now, now I do. Now I'm scared. What am I going to do? I don't know. I have my two little babies in the house. Reporter: Who's going to take care of you if you get sick? I mean, my mom can help me out, but. It's hard, but we'll go through this. Does it fall in the mild category, his lungs are really concerned. Something we'd be really concerned about. His oxygen saturation is good. Blood pressure is good, blood sugar is good and not running a fever right now. Reporter: The firefighters offered to take Martine to the hospital, cautioning he may be waiting there for a while, because he's not sick enough to warrant immediate attention. Is this a typical call? At merriville, there's a proud tradition of families living together, unfortunately, that's the situation for affordability when they're all under one roof. Reporter: Chris west says it's a multi-generational families in merriville that may inadvertently help spread the virus there. We have a lot of families that live together. They grow up in the house, they stay in the house. The kids grow up in the house. So yes. Usually when one person gets it the whole house is going to get it. Reporter: Across the U.S., Latinos and African-Americans contracting the virus at a rate three times higher than their white neighbors, they're also twice as likely to die from the virus, arresting the virus' onslaught depends on testing, which Phoenix' mayor tells us is near total collapse. We are the world's leading economy. We ought to be able to provide more resources for our sickest residents months into the covid-19 virus. Reporter: This is a free testing site in south Phoenix, an area underserved in testing. It's run by a non-profit organization. And the goal is to try to test 2,000 people a day. It opens at 6:00 A.M., but people begin lining up in the middle of the night. Including three generations of Kiana Cole's family. What time did you get here this morning? We got here about 12:31. Reporter: Why was it so important to get here early? So we could have a spot in line. We wanted to be able to get tested today. Reporter: Is it worth spending the night in a car with an 80-year-old? Yes? I say yes. Reporter: Yeah? Because it's our lives and the lives of our families that we have to protect. So we need to know. Reporter: The site like so many, can't meet demand, turning away people like Neil Mack who waited five and a half hours the last time he came. So today he showed up at 1:00 A.M. Phoenix is a massive city. It's privately funded by an Ngo. Reporter: The Suggs offered at 4:00 A.M. They cannot afford to pay for this. There's nowhere you can go in Arizona and get this for free. People with money do get tested, like sports teams, baseball teams. President, anyone can get tested at any time, but every it day middle income to lower income, this is our only option. Are your speaking publicly about the virus in over a week, Arizona governor Doug Ducey admitting loosening the stay-at-home orders in may was the primary cause for the rapid escalation of cases in June. This positivity is too high. What it means is that the virus is widespread. We know there's a reporting lag. Some of the testing is delayed by seven days because the testing centers are so overwhelmed. Reporter: Dr. Sam durani was with me two weeks ago when president trump held a rally in phone he was so shocked by the lack of people wearing masks he started snapping pictures of the crowd. Definitely about a thousand people here. What percentage are wearing a mask? About 1% to 5%. Reporter: In a city going through a surge right now, what does that mean? It's not good. Any mass gathering right now is going to prop gate the spread of We're doing so well after the it's gone away. The situation is obviously worsened. In the last two weeks, hospitalizations have gone up by about 80%. It's been a rapid increase. The more activity that is happening in our economy the more the spread will continue. Again, validation that you are safer at home. Reporter: That safer at home suggestion only effective if everyone in your home is negative for the virus. And ideally, Lopez's boyfriend martin molina should have been able to isolate himself when he came home from the hospital, waiting for results, but that's not their reality. Is there a place where he can have a room to his own without everybody around? To be honest, no. Reporter: Are you concerned at all that he might infect the rest of the family? I was concerned, because we all live together, and my babies, my two little babies, they're my life. Reporter: Late today Marr teen got his test results back. He has covid-19. I'm Matt Gutman in Phoenix. Our thanks to Matt.
This transcript has been automatically generated and may not be 100% accurate.