This reminds me of the situation in a rural Utah county about 10 years ago, where a local nurse noticed a high level of still-births. After she tried to draw public attention to the alarming trend, she started getting death threats and visceral hostility from the community, especially from those who worked for the oil industry.
Hopefully those asking questions about these cancer rate increases in Iowa don't get the same treatment.
Article about the Utah situation for those who are interested.