"We now know that it is the very diluted amounts of chemicals that [have the potential to] cause the most damage because they behave just like hormones," Parker said. "The quantities are so small you can barely measure [them], but they have a disproportionate effect."
Hayes' study was publicized in a press release several years ago by ForestEthics, an environmental nonprofit intimately involved with campaigning against SPI's environmentally destructive practices.
"After that release, we started getting calls from families," said ForestEthics communication director Will Craven. "One family had a six-year-old daughter who developed brain cancer."
Craven said the family lived across from one of SPI's mills and close to clearcut areas. He had heard of families developing severe endocrine issues where they could no longer digest fruit or sugar.
Pawlicki cites studies done internally by scientists about the biodiversity of SPI's land, stating that the proper measures have been taken to put aside enough land for endangered species like the spotted owls and that the effect of the herbicides are negligible if not insignificant.
"People make allegations all the time about us but there's just no proof," said Pawlicki. "Show us the proof, tell us the evidence that we're harming anything."
Marily Woodhouse, a resident of the Battle Creek area who has been a particularly passionate adversary of SPI, has spearheaded efforts to collect sufficient information in order for the Central Valley Regional Water Quality Control Board and the California Natural Resources Agency to take legal action; a process she said SPI has tried to undermine.
"SPI has given out the Water Board report and disparaged the way we collected the sample at public meetings," Woodhouse said in an email conversation. "We collected the sample the way the lab instructed us to."
However, these studies have a financial limit. Some tests can cost up to thousands of dollars, and ensuring that the tests are targeting specific herbicides used by SPI can be a guessing game. SPI is only required to disclose chemical use to the California Department of Pesticide regulation once a month and a yearly report can be requested, but this information is not disclosed to the public at the time of application.
The Water Board, a subsidiary of the Environmental Protection Agency, has conducted water tests and found no significant amount of chemicals in nearby watershed, but Parker said she believes this is because the agency doesn't test for the specific chemicals used by SPI.
"Although they could request this information from the industry, the water board doesn't know which chemicals are used, the quantities, or locations where they are applied," Parker said. "Lack of information and inadequate testing ensures that the company is able to continue doing business."
Residents and environmental groups have filed several lawsuits against SPI for more than 34 environmental and health policy violations, but have not been successful in curbing SPI's destructive practices. According to legal experts, this is not necessarily because they don't have a valid case.
"When you're challenging these actions by SPI, what you're really doing is challenging a decision by a state agency for approving their logging plan," said Justin Augustine a staff attorney at the Center for Biological Diversity. "The agency can get deference from the court when it makes a good decision or a bad decision."
The state agency Augustine is talking about is the California Department of Fire and Forestry Protection (Cal Fire). In the hierarchy of state agencies, Cal Fire sits next to the Department of Fish and Game and both are directly under the Natural Resources Agency. Each department plays a role in monitoring and enforcing logging practices and code violations.