Adults exposed to poisonous levels of lead as children here now suffer reduced nerve function, neurological problems and infertility at higher rates than other adults.
Former Silver Valley children also report more cases of anemia, arthritis and urinary tract conditions - problems often linked to lead exposure.
These are the results of a long-awaited federal study of adults who were age 9 or younger in Shoshone County in the mid-1970s.
The study, released Wednesday, is the first to examine actual health effects of people who were kids in Pinehurst, Kellogg, Smelterville and Wardner when toxic mining-related lead and zinc emissions were at their highest.
Health experts long have suspected growing up in the shadow of the Bunker Hill mine could lead to a legion of mental and physical disorders.
Previous studies, however, merely documented high lead exposure and risks.
“It’s certainly significant,” said Jerry Cobb, who supervises lead monitoring in the Silver Valley. “It shows there are problems suffered by those people.”
Scientists with the federal Agency for Toxic Substance and Disease Registry last year tracked 1,466 current and former lead-exposed valley residents and interviewed 917. More than 280 of them were taken to Spokane and subjected to a battery of surveys and medical tests.
Investigators evaluated motor skills, coordination, vision, vocabulary and sensitivity to vibration. They tested kidney and nervous system functions and interviewed participants about other medical conditions. A similar group of Spokane residents was tested for comparison.
“They had us recall number sequences, they did balance tests and they shocked us to check our response time,” said Cal Davis, 30, of Pinehurst. “I thought I did pretty good.”
As a group, the Silver Valley residents - who as kids had lead levels four to eight times higher than what’s now considered safe - did poor on tests showing how well the nervous system worked.
Twice as many Silver Valley residents - 43 percent - reported experiencing five or more neurological disorders such as reading, memory or concentration problems. The Silver Valley group also performed worse on grip tests, was less able to feel vibrations and had more difficulty identifying missing pieces of visual patterns than the other group.
The same held true for infertility. While 4 percent of the Spokane group reported being unable to conceive, the rate jumped to 10 percent for Silver Valley residents.
Interpreting the results is difficult.
Researcher Lynette Stokes, an Atlanta-based epidemiologist, would not say the Silver Valley kids faced lead-related “sicknesses.” She characterized the maladies as “effects” linked to lead exposure during childhood development.
“Each of these effects is not an illness,” she said. “An individual who can’t feel a vibration is not sick.”
But the study did indicate the Silver Valley group more often faced learning and retention problems.
“The more lead, the poorer the performance in cognitive tests,” she said.
For Davis, who lives on disability payments, sees specialists for sleep disorders and can’t concentrate long on anything, the study answered nagging questions.
“You pick up a magazine, you read that these things are all related and you wonder ‘is that what’s wrong with me?”’ Davis said. “I think now that that’s some of it.”
But others, like Brenda Woodbridge, 29, aren’t sure what to conclude.
Woodbridge lives in Seattle, is healthy and not worried that her childhood in lead-exposed Pinehurst might haunt her.
“With cancer and everything else out there these days, it’s out of my control,” she said.
But she thinks of her younger brother and his learning disabilities. He was born in 1974, after a smelter fire that kicked off the worst period of pollution in Pinehurst.
She found him in bed as a child, crying about how kids and teachers “thought he was dumb.”
“That’s pretty upsetting, having somebody close to you, and having to wonder if something could have caused that,” she said. “But there’s never a way to prove it.”