Mexican president Andrés Manuel López Obrador’s attempt at engineering “equity” among energy producers may have backfired as small coal operations are proliferating and could be putting workers at risk.

As a move to shore up Mexico’s state-owned power utility two years ago, the president promoted the revival of coal-fired power plants in the northern parts of the country.

Part of the new policy included provisions that gave preference to small coal mining operations, with the state power utility committing to purchase roughly two-thirds of its coal supply from small mines.

This had the effect of reinvigorating the practice of working “pocitos,” according to AP News.

A pocito is a tiny, narrow mine that usually does not include auxiliary shafts or sophisticated mining equipment.

Governed by Mexican labor laws, pocitos largely operate unimpeded by state oversight, running under authorities’ radar and using rudimentary mining techniques.

These coal mines garnered international media attention this month when a pocito flooded on August 3 in Sabinas, Coahuila, roughly 70 miles southwest of Eagle Pass, Texas.

Five miners were rescued, but 10 are still trapped. It is unclear whether they are still alive. There has been no contact with the men since early August, and hopes are beginning to fade that they will be found alive, if at all.

The flooding was caused by a neighboring abandoned coal mine that had flooded. A wall of water intruded into the working pocito and blew out its wooden support structures.

Miguel Riquelme, the governor of Coahuila, where the flooded pocito is located, criticized the state power utility for the coal-purchasing policy and, by extension, President Obrador, stating:

“[Their] brilliant idea of buying more coal from the smallest producers, and less from big producers, gave rise to a black market that wound up in the exploitation of mines that lack the safeguards needed to protect the lives of the workers.”

The subdirector of purchasing for the state power utility, Miguel Alejandro López, defended the institution’s purchasing policy, pointing out it was only following President Obrador’s orders:

“We had to have the mindset of favoring the [smaller producers] because we had to make their economic conditions more equal. Because as [Obrador] has said, one of this country’s main failings is inequality.”