The North Carolina legislature has approved a law that proponents say is aimed at protecting businesses from property theft. But critics of the law say it is actually meant to silence whistleblowers who want to expose wrongdoing on factory farms and other businesses.

Known as ag-gag laws, bills like North Carolina's have historically sought to protect meat and poultry producers against employees who document health or safety violations inside slaughterhouses.

North Carolina's new law is "deceitful," said Matthew Dominguez of the Humane Society of the United States (HSUS), which fought its passage.

"It's a very broad and dangerous ag-gag bill because it doesn't just affect agriculture. It affects nursing homes, daycares, veteran facilities, anywhere where you have people that are vulnerable," Dominguez told VICE News.

The law prohibits employees from recording in "nonpublic" areas of their workplaces. And, say critics, it implies that releasing any footage to the public would be a violation of what the legislation calls an employee's "duty of loyalty to their employer." Whistleblowers could be fined up to $5,000 per day. The law also singles out data and document theft, planting surveillance equipment, and "organized retail theft."

"This bill was designed to chill the ability to do whistleblowing exposes into factory farms," Dominguez said. "The fact that they expanded it into other businesses was to really be the wolf in sheep's clothing — they wanted to provide a talking point, and say, 'Oh, this isn't just about agriculture,' when that was their prime reason for it."

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North Carolina is the country's second largest pork-producing state, lagging only behind Iowa, according to the most recent US Department of Agriculture (USDA) statistics. In 2012, the state's pig sales were worth $2.9 billion.

Ag-gag laws are a response by industry to undercover investigations. One of the most famous was a 2008 HSUS expose about a Chino, California slaughterhouse, which spurred a recall of over a million pounds of beef.

"Just in the last four years over 30 ag-gag laws in more than 15 states have been introduced across the country," Dominguez added. Most of those failed, but North Carolina follows Iowa, Missouri, Utah, and Idaho in the passage of such laws.

Nationwide, ag-gag laws have evolved, says Will Potter, who documented government surveillance and prosecution of environmentalists in his book Green Is the New Red.

"Originally these laws were explicitly targeting animal welfare groups and explicitly prohibiting photography," he told VICE News. "That didn't go [over] very well with the public."

But legislatures have continued to discuss bills on whistleblower activity, said Potter, and have tried to include requirements that job applicants disclose if they have worked for animal rights groups. Other ag-gag laws proposed to require workers to submit to their employers — or the police — any footage they had taken.

North Carolina's law doesn't mention agriculture, specifically, and instead focuses broadly on businesses.

"That's all bullshit," Potter said. "This is about undercover video and they're just trying to package it in a new way to try to sneak it through."

The legislature passed the bill — HB 405 — by overriding a veto from the state's governor, Pat McCrory.

"The veto of HB 405 publicly exposed its flaws of not fully protecting current employees who report illegal practices in our businesses, including nursing homes, child care centers and veterans treatment facilities," McCrory said in a statement.

North Carolina Representative John Szoka, a Republican who sponsored the legislation, said it's wrong to call it an ag-gag bill.

"There are ag-gag bills out there, but this is not one of them," Szoka told VICE News. But he added: "It certainly does cover food processing."

The aim of the bill, he said, is to stop corporate espionage — like someone stealing information from a rival business. He says the 1992 Food Lion case, in which ABC News reporters posed as grocery store employees, was a motivation for the law. A court later decided that the ABC employees had acted illegally by secretly filming in the stores. Szoka said the investigation hurt Food Lion's business and was bad journalism.

For scenarios like witnessing physical abuse in nursing homes or health and safety violations in a slaughterhouse, workers should go to the proper authorities, like the police or the USDA, he said.

"That's the part where nobody has explained to me enough to convince me that it's better going to a news organization than it is to the authorities to stop whatever they see going on right then and there," he said.