GRANTS PASS, Ore. (AP) -- Federal scientists have agreed to review the environmental evidence gathered by state agencies after rural residents in Curry County complained they got sick after being sprayed by herbicides meant for nearby timberlands.

Scientists from the federal Agency for Toxic Substances and Disease Registry will work with Oregon state agencies to determine whether enough environmental data has been gathered to make a meaningful determination of the pesticide exposure in the community, spokeswoman Susan McBreairty said Thursday.

If there is enough data, the scientists from the agency — a branch of the Centers for Disease Control and Prevention — will do the evaluation.

The pesticides watchdog group Beyond Toxics of Eugene had petitioned the agency to get involved in the investigation into complaints last October from two dozen residents of the Cedar Valley area north of Gold Beach. They complained of vomiting, coughing, loss of balance, skin rashes, blurry vision and other ailments. Some also reported their animals were sickened. They say they want to know to what chemicals they were exposed.

John Burns, assistant chief of the local volunteer fire department, said he hoped the federal review would speed up action on their complaints, particularly letting people know just what they were exposed to, so that doctors can treat them. Nearly three months later, he said, he still suffers nosebleeds and blurry vision, gets tired easily and is unsteady on his feet.

"The biggest frustration for myself and most of the people out here is we haven't been given the actual cocktail mix of what was sprayed on us," he said. "Why is it such a secret that we can't find out what this stuff was that was sprayed on us?"

The Oregon Department of Agriculture has been investigating. In November, department pesticides program manager Dale Mitchell said the agency monitored the Oct. 16 spraying on nearby timberlands owned by Crook Timberlands LLC of Coos Bay. After people complained of being sick, vegetation samples from four properties were taken.

"Our approach is to work in partnership on these issues with other state and federal agencies," department spokesman Bruce Pokarney said. "That has been the case with the Triangle Lake/Highway 36 exposure investigation in Lane County and it will be the case with whatever takes place in Curry County."

On Friday, Crook Timberlands manager Rick Barnes denied their spraying operation was the source of helicopters and spray seen by Cedar Valley residents. He said the helicopter they hired was loaded from a site on their property, and never flew over Cedar Valley. He added that a person from Oregon Department of Forestry was on site monitoring. Barnes said he has identified another spray operation going on that day, and passed the information on to Department of Agriculture. He would not identify the company.

Pokarney said they would have no more to say about the investigation until it was finished.

Lisa Arkin of Beyond Toxics said samples should have been taken from more places, as well as from a creek that local people use for drinking water.

She said they had also asked the federal agency to talk to the people complaining of illness. Arkin added that while the Department of Agriculture originally reported one helicopter involved, local residents reported seeing two different helicopters.

The Oregon Public Health Division has a longstanding cooperative agreement with Agency for Toxic Substances and Disease Registry to look into the effects of chemical exposures and human health, said division spokesman Jonathan Modie. Pokarney said the federal agency has not contacted the Department of Agriculture yet. Oregon Department of Forestry spokesman Dan Postrel said they have not been contacted, either.

Herbicides are commonly used on privately owned industrial forests to control bush, allowing tree seedlings to grow more quickly.