MIAMI, NOV. 28 -- A woman died two days after pest control company workers who did not know she was in her house sealed a tent around the structure and pumped in poison gas, police said.

Caridad Clausell, 75, died Thursday night. Until an autopsy is performed, her death is unclassified.

Police said Dolphin Exterminating Corp. employes went to the house Tuesday to perform the $375 job aimed at killing dry wood termites. Workers fixed a tarpaulin in position and placed fans in the house. They asked Clausell and her sister, Maria, 81, who also lived there, to lock the door when they left.

The pest control workers, apparently believing the house was vacant, began fumigating.

"The exterminating people worked real fast," said Emelina Garcia, a cousin. "She had never left."

"The crews sealed the tent, put clips like big metal clothespins up and down the seams," said Detective Nelson Andreu. "They put an irritant, a chemical like tear gas, in first, so anyone inside would cough and come out. They then opened the valve and put the methyl bromide into the house. They said they walked around and made sure there were no leaks, made sure there were no holes in the seams . . . . "

Dinora Bris found Clausell slumped on a small back porch.