Amini had spent four days in intensive care before succumbing to his injuries. Another activist, Chiako Yousefinejad, died a day earlier in the same hospital.
The first to die from the group was Hamid Moradi, a lawyer and environmental activist from Sanandaj in Iran's Kurdistan province, according to the Kurdistan Human Rights Network (KHRN).
A blaze on Mount Abidar broke out on July 24, prompting a rapid response from local environmentalists and volunteers determined to stop its spread.
But their efforts were hampered by a lack of firefighting resources and proper protective equipment — a chronic issue in the Islamic Republic's handling of environmental disasters.
Their deaths have sparked an outpouring of grief and condemnation from civil society and environmental advocates, many of whom accused authorities of systemic neglect and mismanagement of natural disasters.
Among those voicing outrage was Nobel Peace Prize laureate Narges Mohammadi, who posted a tribute on Instagram calling the men the “brave defenders of Kurdistan’s environment.”
“Hamid, Chiako, and Khabat were consumed by flames so that Mount Abidar would not burn — so that life could remain green,” she wrote.
“We are a people who step in when competence, accountability, and the fulfillment of government duties are absent — a government that not only fails to protect the environment, nature, and the lives of those who care for it, but has turned nature into a battleground for exploitation and the pursuit of power, even at the cost of destruction," Mohammedi added.
Twenty-five environmental defenders have died in forest and grassland fires across Iran over the past decade, according to activists.