BEIRUT, Lebanon — Rescue workers who had spent days searching for a possible survivor in a building destroyed by a huge explosion last month all but gave up hope on Saturday, saying they had no new indications that anyone was alive under the rubble.
The search had captivated Lebanon since a sniffer dog named Flash drew rescue workers to the building, providing a dramatic glimmer of hope a month after the blast tore through Beirut, devastating residential neighborhoods and killing more than 190 people.
But that hope has since faded, as rescue workers dug day and night through piles of rubble in a historic house destroyed by the blast, finding nothing.
“Technically speaking, there are no signs of life,” Francisco Lermanda, the coordinator of Topos, a rescue group from Chile, told reporters Sunday night.
Rescuers had searched 95 percent of the building, he said, but would continue working until they had cleared the rest, probably finishing overnight.
The end of the search with no result would mark another grave disappointment for Lebanon, which was suffering from political instability and an economic meltdown even before the explosion ravaged entire neighborhoods, injured 6,000 people and caused billions of dollars in damage.
The explosion, caused by the sudden combustion of hundreds of tons of hazardous chemicals that had been improperly stored in the Beirut port for years, has fueled anger at the government for its failure to take any steps to prevent the disaster.
People across Lebanon had diligently tracked the search, with television stations broadcasting live from the site and journalists posting frequent updates on social media. Dozens of workers joined in, including Civil Defense crews from Lebanon and volunteers from abroad who came to help after the blast.
Fueling hopes that someone could have miraculously survived under the rubble a month after the blast despite Beirut’s very hot and humid summer weather were announcements from Topos that its sensors at the site had picked up pulses that could be from a trapped human.
A French technician produced three-dimensional computer scans of the building to help guide the search, and rescue workers dug with shovels and their bare hands, so as not to harm a possible survivor or damage any human remains.
The Chilean team occasionally asked everyone in the area to silence their phones so that their equipment could get a clear reading, and Flash the dog became a local celebrity, commemorated by a local artist and celebrated in montages on TV.
But by Sunday, most of the building had been searched in vain, and Mr. Lermanda, the Chilean coordinator, acknowledged that the previously detected signs of life had been the breathing of rescue workers inside the building.
On Saturday night, the only remaining area to be checked was under the rubble piled on a sidewalk near the building.
The wider anger at the Lebanese government simmered at the rescue site, where many residents and volunteers accused the state of having failed to live up to its responsibilities since the blast, including by coordinating a comprehensive search for survivors and human remains.
“This dog gave us hope, but it also made fun of the whole system,” said Riyadh al-Assad, a Lebanese engineer assisting with the rescue effort. “This building should have been excavated weeks ago.”
Flash arrived in Beirut with Topos, meaning “moles” in Spanish, less than a week ago to help find victims missing after the explosion. The group was modeled on a Mexican rescue team with the same name that was born out of the spontaneous efforts of Mexican civilians to help emergency workers after a devastating earthquake in 1985.
Similar volunteer groups have formed in Bulgaria, New Zealand and France. Topos Chile has assisted in search and rescue efforts in Iran, Turkey, Haiti and Mexico, among others. At home, it assisted emergency workers after the 8.8 earthquake and tsunami in the central-south part of the country in 2010, and later that year in the rescue of 33 miners trapped half a mile underground for 68 days. Topos from Mexico joined it for both missions.
Mr. Lermanda said in a 2016 interview that the group’s members, who include kindergarten teachers, business owners, students and prison guards, share a WhatsApp group to build teams when disasters strike.
As soon as an earthquake is reported somewhere, he said, his phone fills with messages from other members reading, “available.”
Kareem Chehayeb contributed reporting from Beirut, and Pascale Bonnefoy from Santiago, Chile.