A disturbingly high number of cancer cases outside Boston are linked to a former textile dye-making plant with waste ponds that some children swam in, state health officials concluded Tuesday.

People who grew up in Ashland and swam in contaminated ponds were two to three times more likely to develop cancer than those who had no contact with the water, a seven-year study found.

The cancer rate was nearly four times greater among people with a family history of cancer and who also swam or waded in waste lagoons and contaminated wetlands near the Nyanza Inc. dye plant, the Department of Public Health said.

Investigators interviewed 1,387 people who were 10 to 18 years old and lived in Ashland between 1965 and 1985.

The study found 73 cases of cancer and eight cancer-related deaths. About two-thirds of the cancers were diagnosed before age 35, and many involved rare forms.

Although the contamination was well-known, some residents didn't consider it a risk.

"We had reports to us that one of the things that the old Ashland high school football team used to do when they won a big game was to go jump into the lagoons," said Suzanne Condon, state assistant commissioner of public health.

The study was begun after Ashland resident Kevin Kane, who played sports near the site as a child and once fell in a lagoon, developed a rare cancer as a young man, along with four childhood friends, in the 1990s. He died in 1998 at age 26.

The Nyanza plant operated from 1965 to 1978 in Ashland, a town of nearly 15,000 about 22 miles west of Boston.

"People in the town will tell you, they knew what color of dye was being made on almost any day of the week, because the brook down the street would turn purple or red, or whatever color they were making dye for that day," said Suzanne Condon, state assistant commissioner of public health.

The Nyanza site was added to the federal Superfund cleanup list in 1983. The 35-acre site is near Ashland Junior & Senior High School and is surrounded by homes.

Nyanza's successor companies agreed to pay $13 million of the total $46 million the government has spent on cleanup, said Jim Murphy of the U.S. Environmental Protection Agency.

Murphy said the settlement was not recent, and he could not immediately provide the names of the successor companies.

The government has pursued no illness-related legal claims