“That’s the Rat Trap Door factory,” a garment worker told me, pointing to a little blue door on a windowless wall along National Road 4 in Phnom Penh. “The door is so small it looks like only rats can get in.”

Women in the sewing division of a factory in Phnom Penh, Cambodia’s capital. Women constitute about 90 percent of the workforce in Cambodia’s garment industry.

© 2014 Samer Muscati/ Human Rights Watch

It didn’t look like a factory. Unlike larger, registered factories, this one had no sign. People working there had no clue what it was actually called, he said. They didn’t have worker identity cards. They didn’t know whether the factory was registered with the National Social Security Fund (NSSF), which provides employment injury and worker health insurance, or whether it had registered the workers.

Cambodia has many nameless factories. At the “Cow Poop factory,” cows relieve themselves at the factory entrance. Then there’s the Paper Flower factory, the Mango Tree factory, and those identified by an owner or manager’s first name. Garment workers in Cambodia may have a good sense of humor about these shadowy, unidentified factories, but people who work in them are more vulnerable to abusive labor practices that violate local law and international norms.

This is the underbelly of Cambodia’s garment industry and the lowest rung of the international apparel industry. Small factories often act as subcontractors for larger export-oriented factories, but are subject to far less scrutiny or monitoring. Many are secretive with their workers, and their working conditions and business practices stay largely under the radar. These small factories help cut costs for larger factories that are subject to more scrutiny. And they become all the more relevant with the recent increase in the garment sector’s minimum wage in Cambodia to $153 per month.

Earlier this year, we spotted about 50 small factories around Kandal province, near Phnom Penh. Some were tiny, but driving past them, I could see busy workers and heaps of garments through the windows. Many factories were advertising jobs. It’s impossible to estimate how many such factories mushroom in response to seasonal garment orders.

Many of these factories looked like huge tin sheds with little ventilation. Others look like houses. One or two had barely visible names, but most had none.

With the help of Cambodian labor rights defenders, I was able to speak to workers from some of these factories. They all said the same thing about not knowing the name of their factory and not thinking it was registered under the NSSF. The workers either didn’t have factory identification cards or, if they did, they were scrawled merely with their name and division—no factory name. Workers said their factories were getting “business” from larger factories in surrounding areas, which are mostly export-oriented. They didn’t know the brands that sourced the garments: At the production stage they saw, there were no labels.

These factories typically employ workers on a piece-rate basis between April and November, or the “high season,” the workers told me. The factories close when business wanes.

The shadowy nature of these factories hurts labor rights in Cambodia. Their workers should benefit from labor protections, including through the NSSF. Earlier this year, fund officials and the Labor Ministry took an important step by adding health care to coverage for injuries under the social security fund. Garment workers in these small factories do get sick and injured, and need these benefits. But if the factory doesn’t register them, they’re left out.

Some problems in the garment industry are hard to fix. But this one isn’t. The Cambodian government should publicly announce a period for all factories to register with the NSSF, and face penalties if they don’t. It should also publish a list of all factories, by sector, that are NSSF-registered.

Global brands have long benefited from the labor of workers in many subcontracted factories, often without authorizing their production role. While most brands have codes of conduct forbidding unauthorized outsourcing to smaller factories, their purchasing practices can drive such outsourcing. Because production at these sites is unauthorized, such factories do not fall within a brand’s supply chain monitoring. In rare instances, brands that have detected the use of these factories have absorbed them into their supply chain.

Global apparel brands should urge the Cambodian authorities to ensure that all factories and workers are registered under the NSSF, and press the government to publicly list registered factories. While brands should do much more to protect workers in small, subcontracted factories, encouraging the Cambodian government to take these steps is at least a step in the right direction.

The Cambodian government and global brands have an opportunity to coalesce behind a common goal: ensuring that all workers—in factories big and small—are covered by the NSSF and enjoy their full rights under the law.