Roger Christie, Carson's great-nephew, said he could tell how ill she was and perhaps at some level he knew she was dying. Carson adopted him when he was five and she was just shy of 50.
"I think subconsciously, I knew she was dying," he said.
Through sheer determination, Carson participated in an hour-long CBS News documentary on pesticides, which aired not long after "Silent Spring" became a national best seller.
"Can anyone believe it is possible to lay down such a barrage of poisons on the surface of the Earth without making it unfit for all life?" she said in the documentary.
While Carson didn't contend that chemical insecticides must never be used, she faced harsh opposition.
"Well, the one guy, the chief critic was — as they say, he would have made a great villain in a Bela Lugosi movie," Christie said.
His name was Dr. Robert White-Stevens, a spokesman for the chemical industry.
"The major claims in Miss Rachel Carson's book, 'Silent Spring,' are gross distortions of the actual facts, completely unsupported by scientific experimental evidence, and general practical experience in the field," he told CBS more than four decades ago. "If Man were to faithfully follow the teachings of Miss Carson, we would return to the Dark Ages, and the insects and diseases and vermin would once again inherit the Earth."
"He was way over the top," Christie said. "'If Miss Carson has her way, the — hundreds of thousands of people would be starving in the streets tomorrow!'"
When CBS turned to government experts, the questions were many, but the answers few. Dr. Page Nicholson, water pollution expert, Public Health Service, wasn't able to answer how long pesticides persist in water once they enter or the extent to which pesticides contaminated groundwater supplies.
Even still, Christie said he knew his aunt was having an impact when President John F. Kennedy mentioned the book at a press conference.
"And my Uncle Jack, John F. Kennedy, read her book, and said, 'I'm gonna appoint an independent commission to investigate whether it's true or not," Robert Kennedy said. "That commission met for almost a year. And then at the end of that time period, [they] came out and said that essentially everything in Rachel Carson's book was true."
Rachel Carson died in 1964, just 18 months after "Silent Spring" was published. She would never know that her crusade against pesticides forever changed the way Americans view their environment.
DDT was banned in this country in 1972. Carson's work also led to the creation of the Environmental Protection Agency, and without her pioneering efforts, we might not be marking Earth Day.
"Silent Spring" foreshadowed the debate over global warming, clean energy and organic food.
But to best understand Carson's legacy, there's no better place to look than Catalina Island, just off the coast of southern California — home again to the bald eagle.
The eagles had all but disappeared after DDT was dumped into local waters, which led egg shells to become so thin that chicks couldn't survive. But just this month, for the first time in decades, eggs left in nests in the wild hatched on their own.
Ann Muscat, president of the Catalina Island conservancy, believes the eagles owe it all to Rachel Carson.
"So I think that wherever she is right now, she must be looking down on Catalina and thinking, 'This is really a wonderful occasion,'" Muscat said.