Follow me. One of America's biggest secrets is that farms practically don't exist anymore. The animals we eat are grown inside giant hidden factories. Since 2012, I've been secretly planning a project to expose these factory farms using the highest tech spy equipment available--drones. This video provides just a sample of what I saw during only a few days of filming.

You're looking at a lake of toxic pig feces and urine the size of four football fields. That's because thousands upon thousands of pigs are inside of these buildings. Their waste falls through slats in the concrete floor and it's flushed directly into this giant open-air cesspool. How many of these kinds of factories are there? In North Carolina alone, there are over 2,000 and the consequences are disastrous.

Associate Professor of Epidemiology, Gillings School of Public Health, University of North Carolina. The waste falls through the floors, it's flushed out into an open pit, a cesspool. It's easy for a big hog operation to have as much waste as a medium size city. Of course the pit will fill up so it has to be emptied and they're emptied by spraying the liquid waste.

Yes, you heard that right.

If you're familiar with a garden sprayer, they're gigantic versions of that. So they're making droplets, fine mists, out of this liquid waste. And that can drift downwind into the neighboring communities.

Former Pig Factory Farm Owner. I shut my hog operation down and I got out of it. I couldn't, I just couldn't do another person that way, to make them smell bad. It is a cesspool that you put feces and urine in, a hole in the ground that you dump a toxic waste in. I've seen dead hogs in them and stuff like that.

People can't open their windows, they can't go outside.

I've seen it. I've talked to the people, I've seen the little children that say 'Mom and Daddy, why do we have to smell this stuff?' You get stories like 'I can't hang my clothes out because the feces odor comes by and attaches itself to your clothes.' And then people will say 'We're scared to invite neighbors.'

It can, I think very correctly be called, environmental racism or environmental injustice that people of color, low income people bear the brunt of these practices.

This is where they spray out waste on us. This is about eight feet from my mother's house.

What is it like when the mist...?

You think it's raining.

Really?

You think it's raining. We don't open the doors or windows, but the odor still comes in. It takes your breath away, then you start gagging and you get headaches.

There are a number of studies of asthma and asthma symptoms, particular in children, near these facilities. Among adults there are reports of several types of upper respiratory symptoms. These pollutants are affecting people's blood pressure.

Who's responsible for all of this? Smithfield Foods, specifically the subdivision Murphy Brown, which controls the factory farms shown in all of the drone footage in this video. Smithfield is by far the largest pork producer in the entire world and inside these buildings there is something else entirely.

Mercy for Animals. Pigs are really intelligent animals. They are more intelligent than dogs. They are more intelligent than cats. In the average pig barn there can be hundreds, if not thousands, of pigs crammed into this one sprawling indoor space. Their entire life is spent standing on concrete floors. Mother pigs are locked in metal cages so small that they literally cannot even turn around for months at a time.

Undercover Footage Courtesy of People for the Ethical Treatment of Animals. Undercover Footage Courtesy of The Human Society of the United States.

This is not a partisan issue. We are all opposed to children being made sick, to animals being abused, and to everyday people's lives being ruined by the stench of cesspools in their backyards. These thousands of lakes of toxic waste must be among the most bizarre and disturbing environmental phenomena that have ever confronted America and they've been kept well hidden from the American public for long enough.

FactoryFarmDrones.com

Please visit www.FactoryFarmDrones.com for more information

Directed and Produced by Mark Devries

Assistants Katie Cantrell, Gail Mayer, Alex Melonas

Executive Producer Eric Kurtzman

Special Thanks to Ray Ippolito

Copyright 2014 by Mark Devries

FactoryFarmDrones.com

There may be small errors in this transcript.