CTEC Health Perception Study - Dave Hutchins
As reported back in October, there is a study on health perceptions in the community of Butte
happening now, that is being conducted jointly by the Citizens’ Technical Environmental
Committee and faculty and students at Montana Tech. Here’s CTEC board member Bill
MacGregor describing the study.
BM: “It’s a one-year pilot study funded by NIH through Montana INBRE program run out of
Montana State. We got funded to pursue a hypothesis, to explore a hypothesis, that a
significant gap exists between the perceptions of Butte residents, about health risks living in
Butte, is it safe, and the record of risk reduction associated with environmental cleanup,
reclamation and restoration work undertaken over the last thirty plus years.”
The study consists of two components, a systematic survey of the perceptions of members of
the community and a compilation of documentation of remedial actions and effects. The survey
is in the form of a mailed questionnaire that was mailed out recently and the other data was
collected from various official sources.
BM: “So, we’re surveying to see where the gap between reality and perception is, but also
between the official assessments of risk and anecdotal reports that contradict those. We want
to get that out on the table, so they are taken seriously.”
Raja Nagasetty, a professor in Environmental engineering at Tech and another CTEC board
member, is leading the project. They have received responses from their mail out survey, and
he and two graduate students presented some of their initial findings last Thursday at a CTEC
meeting. Here’s Raja on how they got started.
RN “We started with the literature review, the perceptions at different…35,000 Butte
Loran Brooks, an Environmental engineering student, led the effort to develop the
questionnaire. Here’s Loren talking about how they designed the questionnaire:
LB: “In designing the questionnaire instrument …quantifying perceptions.”
A Likert style is that familiar questionnaire method where a question is asked and then there
are multiple choice answers on a scale, in this case from “very good” to “very bad”.
Sarah Storey, an Industrial Health and Hygiene master student, led an effort to analyze the
consistency and reliability of the survey. They conducted Internal consistency tests and
repeatability tests to ensure the survey was operating as it should. After they, and the MSU Helps lab,
were satisfied they sent it out to 550 adults within the Butte city limits. They received responses from
163 participants, a respectable response rate in the world of mail-out surveys. They found respondents
were not entirely representative of the population, they were skewed toward older, higher income
citizens, but there was a wide enough range to produce some interesting data, and the gaps could be
filled in with other methods.
The survey is divided into five sections, including one on respondent information to establish
demographics. In order to tease out the perceptions as they relate to Superfund they started
with general questions about environmental health, and then asked a similar question as it
relates to mine waste. They needed a way to quantify perceptions, not an easy task, here’s
Loren describing the method:
LB: “This led us to establish a baseline of overall perceptions…lead arsenic and mercury?”
And they did see a difference between the baseline and the perceptions as they relate to
LB: “When we wanted to see if there was a significant difference between…There’s definitely a
gap, and it’s measurable.”
The next section of the survey looked at perceptions related to Superfund activity. It asked
respondents to gauge their familiarity with various projects, such as the Parrot removal or the
Residential Metals Abatement Program, and most seemed familiar with the goings on. Then it
asked them to gauge the effort the EPA and other agencies have made on remedial projects.
Most respondents had a positive perception in this section, agreeing that the EPA and RMAP
were doing at least a somewhat good job of protecting human health.
The largest disparity seemed to be found in the remaining section, the Effectiveness of
Remedial Actions section. These were questions about Cancer occurrence and blood lead levels
in children, and they were associated with published data commonly accepted as fact. The
responses to these questions were decidedly split, with some agreeing with the data, but many
For example, 62% of respondents believed that the cancer incidence rate in Butte is greater
than the national average. The study designers said this is in contrast to published data that
show our incidence rate is statistically the same as the national numbers. That phrase,
statistically the same, is thrown out often when discussing these issues and it can be difficult for
the public to decipher what is meant.
Often what they intend is that the difference is not statistically significant. So, let’s take a
deeper look at what that means. When analyzing something like cancer incidence rates, experts
don’t use the raw numbers, they adjust things so they can be compared directly. For instance,
age is a factor in cancer incidence, so the numbers are adjusted to reflect populations with
similar age distributions. And there are other factors that are similarly accounted for and
adjusted. In the end, you are left with data that can be compared, but there is a range, or an
uncertainty associated with the adjustments.
If the sets of data being compared fall within the uncertainty of each other, we say there is no
statistical significance in the difference. This does not mean they are the same, it means we are
not reasonably sure there is a difference.
There are many potential reasons people in Butte may think we have a higher cancer incidence
rate. Perhaps they have not studied the published data, or maybe they have anecdotal
evidence that they believe more strongly. It is also possible they have seen news of recent
studies that have shown there are higher mortality rates for some cancers that have been
linked to the contaminants of concern in our Superfund site. It would have been interesting to
see how respondents would have answered a paired question about cancer as it relates to
This study, even from this early stage, has shown there are indeed gaps. There are gaps
between the public perception of environmental health and the record of risk reduction. There
are gaps between the perceptions of some of our neighbors. And there are many gaps in the
information, there are many unknowns, and many sources of information. The folks conducting
this study hope we are one step closer to bridging these gaps and that knowing where we are
now will help inform the work ahead.
I’m Dave Hutchins reporting for KBMF.
(Chart from Mt DPHHS report on cancer in BSB. These cancers rated are reported to be “statistically the same” https://www.co.silverbow.mt.us/DocumentCenter/View/14098/Cancer-in-Silver-Bow-County)