Around noon on Friday, September 22, dozens of volunteers in helmets and bright yellow and orange vests convened by the ruins of a factory in the Obrera neighborhood of Mexico City, an area with a high concentration of industry. The building, once a four-story structure with a different company operating on each floor, had collapsed on Tuesday, after a 7.1 earthquake hit central Mexico.

Near the wreckage, and outside the rescue area that the government had cordoned off, a group of women had gathered. They took shade under a tarp emblazoned with the words "Feminist Brigade," bearing a shopping cart full of shovels and boxes of food and water to aid the rescue efforts. Many had just come from digging out rubble, and their boots and clothes were covered with dust and debris.

More than 300 people were killed in Tuesday's earthquake, with more than 180 deaths in Mexico City, where as many as 44 buildings collapsed. Citizens were quick to respond to the disaster, sharing photos of fallen buildings, addresses of rescue sites, and lists of supplies needed through Facebook, Twitter, and WhatsApp groups.

As this information circulated in feminist groups on social media, many saw the need to become more organized in sharing information. So they started a Facebook group shortly after the earthquake hit, and called it The Feminist Brigade. Over the course of a few days, its ranks swelled to over 500 members. The Brigade's mission was simple: to help rescue the marginalized victims of the earthquake, those who may not have anyone else to advocate for them.

The first 72 hours are the most important for rescue operations, but some rescuers report that survivors can be found up to a week or more afterwards. Even when hopes dwindle of finding living survivors, officials still continue searching to be able to identify victims and give their bodies to family members.

There was a reason the Feminist Brigade had chosen this particular factory in La Obrera: Many of the predominantly female textile workers employed there were immigrants from Asia and Central America, and the Brigade members believed some may have been undocumented. "The people in this factory are women, and they are immigrant women in a country where they are very much discriminated against, in a country that doesn't care much about them," said Mar Cruz, a 43-year-old volunteer, who spoke to Broadly outside of the rescue site. "Knowing the treatment that they face in the factories, it was up to us as feminists [to come help]."

"We are women defending women," she added. "We have demanded our right to defend our female comrades and their human rights."

Dozens of people from the Feminist Brigade were still at the site on Friday, three days after the quake, where they alternated between moving rubble and resting outside of the sectioned-off area. Every so often, an official raised his hand in a fist, calling for silence so he could listen for the sounds of possible survivors.

For the Feminist Brigade, this signaled that some workers could still be alive, which led to tension between the volunteers and authorities—many volunteers felt that they hadn't been given enough information, or that they were being intentionally misled. Rescue workers claimed that authorities didn't release an official list of all the people who were working at the time of the earthquake, and some doubted that an official list even existed if the workers were undocumented. The Feminist Brigade suspected the priority of officials was to clean up the scene as quickly as possible to project an image of productivity, rather than to focus on finding and identifying all survivors and victims.

Later that night, authorities would officially end the search for factory workers, saying that the whole area had been cleared. According to Mexican media outlet Animal Politico, 21 victims were found dead, and two were rescued alive—but surviving factory workers told the news outlet that there could have been between 50 and 100 workers in the building at the time of the collapse. Some volunteers stayed to continue searching, concerned that some workers may have been trapped in a basement area.

"A factory with that amount of people wouldn't be able to operate," said Cruz, who still doesn't believe everyone has been found.

This is not the first time vulnerable factory workers have fallen victim to an earthquake in Mexico City. The Mexican capital is highly prone to earthquakes because it's built on a drained lakebed. In 1985, Mexico City suffered its most destructive earthquake, where at least 5000 people died. More than 800 factory workshops were destroyed during the natural disaster, and least 600 female workers died. Countless more were trapped.

The 1985 earthquake brought attention to the poor working conditions of Mexico City's factory workers, who were and are predominantly female. Afterwards, workers formed a labor union, called the Seamstress Labor Union of September 19—the date of both the 1985 earthquake and the 7.1 earthquake on Tuesday.

"The collapse of this factory could have happened in the 1985 earthquake, when many factories fell and thousands of women were trapped, and many killed," said Dominique Draco, a 32-year-old volunteer with the Feminist Brigade. "Like them, these women were also in extremely precarious conditions, without labor rights or human rights. The situation is replicating on a smaller scale, but the history is repeating."

The Feminist Brigade is part of a burgeoning women's rights movement in Mexico, where an average of six women are murdered each day, according to statistics from the UN. In recent months, activists have organized large-scale protests against femicide, the murder of a woman based on her gender. Mexican law categorizes femicide as a separate crime from homicide, but actual femicide convictions remain rare. In recent months, feminists have rallied for justice for women like Lesvy Osorio, who was killed in May near a Mexican university, and Mara Castilla, who was murdered in September after using a ride-share service.