BANGKOK — A chemical spill that devastated the coast of central Vietnam last year claimed another casualty on Monday when a 22-year-old blogger was sentenced to seven years in prison for posting reports on the disaster.

After a brief, closed trial in Ha Tinh Province, the blogger, Nguyen Van Hoa, was found guilty of spreading anti-state propaganda for producing videos and writing about protests over the toxic spill, news agencies reported.

The discharge, which occurred when a new Taiwan-owned steel factory flushed cyanide and other chemicals through its waste pipeline, killed marine life and sickened people along a 120-mile stretch of coastline. It is one of Vietnam’s largest environmental disasters.

Phil Robertson, deputy director of Human Rights Watch’s Asia division, denounced the verdict. “The sentencing of Nguyen Van Hoa shows how profoundly the government’s paranoid desire to maintain political control trumps notions of justice and human rights,” he said.