Asbestos concerns in the 21st century:
The Libby, Montana issue
Mickey GunterUniversity of Idaho
Moscow, Idaho
plus, other thoughts
Talk overview
• Libby overview
• Critical thought(s)
• Basic (?) knowledge
• Teaching idea, approach & information
• Good mineral, bad mineral
• What’s the “real” environmental concern(s)
Libby overview
Am Min (1959)
Libby mining details
• 1923: Start of operations• 1950’s: 1,200,000 tons / year, ~30% vermiculite & 5%
“tremolite” with 1/2 of that being asbestos• 1964: WR Grace buys mine• 1980’s: Medical studies• 1990: Mine closes• 1999: PI & EPA, ATSDR, etc….
Seattle Post
Death statistics (U.S.A./year)
- 2,100,000: deaths
- 600,000: heart diseases
- 500,000: cancer
- 150,000: lung cancer
- 435,000: smoking cigs
- 400,000: (too much) food
- 85,000: (too much) booze
- 43,000: auto accidents
“The dose makes the poison” (Paracelsus, 1567).
290,000,000
Death statistics (asbestos and…)
- asbestosis ~ 300
- silicosis ~ 100
- mesothelioma ~ 300
- airlines & lightning ~ 150
- mad cow disease ~ 0
- snake bites ~ 0
- SARs & countless others < 10
Risk of death vs Fear of death
risk of death
fear ofdeath
- self imposed
- by ignorance
Teaching idea
Teaching approach
• overview of “problem”• define material, properties & analytical stuff• describe diseases & exposures• discuss case studies• discuss risk & societal impact(s) in context• What’s the “real problem”?
Obtaining (accurate) information
Now what?
• Refereed literature• Common sense
– 35,000,000 homes with Zonolite in USA
• Non-biased sources– Whose side are you on?– Where does funding come from, for either side?
• “Correct” government sources– Vital statistics of the USA– Agencies working in “their” area of specialty
0
100
200
300
400
1970 1980 1990
year
deaths
asbestosis
silicosis
Silicosis & asbestosis deaths in the U.S.A.
Gunter 1999
60,000
85,000
110,000
135,000
160,000
1970 1980 1990
year
lung cancer deaths
Lung cancer deaths in the U.S.A.
Libby diseases & on-going issues
• Libby miner studies (1986 & 2003), SMR’s– ~ 250 for asbestosis, mesothelioma & lung cancer
• Local lawsuits• Mr. Crayon, EPA, ATSDR & residents
– 11 asbestosis deaths, no mesothelioma– no elevated lung cancer rate
• MEG lung cancer SMR = 137 (10) & 133 (5) • Tremolite at Libby?• Zonolite in 35,000,000 homes nationwide
Zonolite insulation & respirable asbestos
bag weight = 6,000 grams < 177 m = 65 grams
Background levels of dust
In air: - 0.0004 to 0.01 fibers / cc -> breathe 4,000 to 100,000 fibers / day
(Mossman et al. 1990, Klein 1993)
- 10g / m3 (of 5m sized particles) -> breathe 2,500,000 particles / day(Norton & Gunter 1999)
In lungs: - 80,000,000 “fibers” with 50% asbestos
general population Vancouver, BC (Chrug 1983)
- white-asbestos = 50,000,000 and tremolite-asbestos = 6,000,000general population San Francisco (Chrug & Warnock 1980)
Good mineral, bad mineral?
“Since the benefits of the natural environment in providing essential elements and nutrients are well known, the focus in this book has been on the harmful side of the relationship.” From Geology and Health, Skinner & Berger
25% of world
population at r
isk
Asbestos: good mineral, bad mineral?
Overview of real “superfund” site(s)
Final thoughts
• As scientists, we must be skeptical enough to question anything, while being open-minded enough to consider everything.
• And ……quartz……rant
• And….…worry….…rave