posted 04-30-2003 03:16 PM            

what is the *vista* not as good as it used to be ? snort !

btw, fastwalker is NOT duncan...duncan was,is a libertarian, probably a voting yellow dog democrat...and he certainly does not have the political savy F/W has...he was/is intellectual to a point that makes you sick...[sic] get it ?

hey now kook atleast debate lives here...and it does get hot sometimes...but that's life...and every now and again someone cracks a funny...which makes it all worth while...

posted 04-30-2003 03:35 PM               

quote:

---

since a post was made in the *exclusive* chemtrails forum ?

---

posted 04-30-2003 04:01 PM            

I've always thought that it's hard to bounce ideas off those who think the same as you...

posted 04-30-2003 05:48 PM            

not that there's anything wrong with that...

oh yeah...check this out !

second post from the bottom....

posted 04-30-2003 06:07 PM               

/wave Seek

Thanks for asking!

My job was "abolished" (doesn't get much more harsh than that) and the house I lived in went on the market all in the same week, but now the dust has settled and I have lots of time and no money as opposed to lots of money and no time so...
you'll be hearing from me!

I know I just made Seek's day

posted 04-30-2003 07:16 PM               

Where's that photoshop TR-3B BTW? Been waiting a looooooooooooooooooong time...

Seeker and FW the same person? No way!

posted 04-30-2003 09:30 PM            

read at 'Web Of Deceit' to understand fully

their job is to stifle dissent/truth

at all costs

posted 04-30-2003 09:53 PM            

btw...I think your missing a "t" there lu

go ahead take one of mine...I just bought a fresh pak...

posted 04-30-2003 10:30 PM            

and I'm just livin' in his world

I think it's about time to whip out the dialectizer

posted 05-01-2003 03:24 AM            

one can post a thousand times the equivalent of
2' plus 2 equals four '
and debunkers will still demand more proof:

In fact, the technology already exists. In 1975, the US Navy patented a device for producing "a powder contrail having maximum radiation-scattering ability." The powder contained a mixture of 0.3 micron-sized titanium dioxide pigment particles coated with 0.007 micron hydrophobic colloidal silica and 4.5 micron particles of silica gel. The purpose of the apparatus was "to generate contrails or reflective screens for any desired purpose."

The Welsbach Patent proposed using "very fine, talcum-like" powder of 10 to 100 micron-sized aluminum oxide to produce a "pure white plume" in the sky.
In 1994, the Hughes aerospace company was issued a remarkable patent. The Welsbach patent "for Reduction of Global Warming" proposed countering global warming by dispensing microscopic particles of aluminum oxide and other reflective materials into the upper atmosphere. This "sky shield" would reflect one or two percent of incoming sunlight. The patent suggested that tiny metal flakes could be "added to the fuel of jet airliners, so that the particles would be emitted from the jet engine exhaust while the airliner was at its cruising altitude."

Computer simulations by Ken Caldeira at California's Lawrence Livermore National Laboratory (LLNL) calculated that employing Welsbach's chemical-sunscreen technology could stop warming over 85 percent of the planet, despite an anticipated doubling of atmospheric carbon within the next 50 years. LLNL estimated the cost of creating thisso-called Sky Shield at $1 billion dollars a year - a cheap fix to avoid threatening the massive profits of the oil industry.

At the 1998 International Seminar on Planetary Emergencies, Edward Teller, the "Father of the H-bomb," presented his Next Big Idea. Teller called for spreading reflective chemicals over the Earth to act like a mirror-shade. If it was impossible to protect the entire planet, these chemical sky shields could, at least, be extended to cover allies who secretly agreed to allow this unprecedented geo-engineering experiment to be carried out over their territory.

In the July-August 1998 Science and Technology Review, Teller argued that the Sky Shield offered a more "realistic" option for addressing global warming than drastic cutbacks in CO2 emissions.
In the spring of 1998, rain falling through heavy chemtrails over Espanola, Ontario was found to contain concentrations of aluminum particles seven times higher than permitted by Canadian health safety laws. Provincial health officials ordered tests after residents began complaining about severe headaches, chronic joint pain, dizziness, sudden extreme fatigue, acute asthma attacks and feverless "flu-like" symptoms. The results of the test were not released.

The reports of illness all came from residents inside a 50-square-mile area who complained that they had been subjected to "months of spraying" by photo-identified US Air Force tanker planes. The USAF denied the intrusions.
high traces of aluminum and quartz in particulate and rainwater samples. These concerns combined with associated respiratory ailments
A Harvard School of Public Health team determined that particulates with a diameter less than 10 microns (one-tenth the thickness of a human hair) pose a serious threat to public health. On April 21, 2001, the New York Times warned: "These microscopic motes are able to infiltrate the tiniest compartments in the lungs and pass readily into the bloodstream, and have been most strongly tied to illness and early death, particularly in people who are already susceptible to respiratory problems."

On December 14, 2000, the New England Journal of Medicine reported that inhaling particulate matter of a size 10 microns or smaller leads to "a 5 percent increased death rate within 24 hours." Teller's sunscreen calls for spraying 10 million tons of talcum-fine reflective particulates of 10 to 100 micron sizes.

In the spring of 1998, rain falling through heavy chemtrails over Espanola, Ontario was found to contain concentrations of aluminum particles seven times higher than permitted by Canadian health safety laws. Provincial health officials ordered tests after residents began complaining about severe headaches, chronic joint pain, dizziness, sudden extreme fatigue, acute asthma attacks and feverless "flu-like" symptoms. The results of the test were not released.
***

To contrast Chem-trail effects with the most common diagnosis for the same symptoms:

Reports from earlier outbreaks describe the mild form of WNV infection as a febrile illness of sudden onset often accompanied by
malaise headache
anorexia myalgia
nausea rash
vomiting lymphadenopathy
eye pain
The full clinical spectrum of West Nile fever has not been determined in the United States.
Severe Infection
Approximately 1 in 150 infections will result in severe neurological disease.
The most significant risk factor for developing severe neurological disease is advanced age.
Encephalitis is more commonly reported than meningitis.
In recent outbreaks, symptoms occurring among patients hospitalized with severe disease include
fever gastrointestinal symptoms
weakness change in mental status
A minority of patients with severe disease developed a maculopapular or morbilliform rash involving the neck, trunk, arms, or legs.
Several patients experienced severe muscle weakness and flaccid paralysis.
Neurological presentations included
ataxia and extrapyramidal signs optic neuritis
cranial nerve abnormalities polyradiculitis
myelitis seizures
Although not observed in recent outbreaks, myocarditis, pancreatitis, and fulminant hepatitis have been described.
Clinical Suspicion
Diagnosis of WNV infection is based on a high index of clinical suspicion and obtaining specific laboratory tests.
Quite similar symptoms.

People exposed to chemtrails should see a doctor, just in case it is West Nile. Or is that vice versa?
***
The jet looked like a cargo transport.
As it flared in to land, a dark football shaped protuberance below the fuselage was silouetted.
From the rear of the football a 'smoke' trailed aft.

Afterwards an afternoon dew was visible on lawns.

I stayed inside the house, windows closed, dehumidifiers filtering air.

Neighbors who went for walks, suffered flu like symptoms.
A nearby jail was closed because all inmates had a sudden mysterious disease, a spike in school absences was explained as a flu like illness.

One state away, a friend called and said airplanes are flying over very low lately.

He asked what makes contrails. I explained hot moisture laden exhaust in cold air causes contrails.
"How about low altitude contrails?"
"No such thing below the artic. Stay inside for a day or two."

All his neighbors came down with flu like symptoms.
One died from "West Nile"

"How can we get West Nile with no mosquitos?"
He asked in the next phone call.
"Respiratory distress caused by inhalable particulates of toxic minerals can be mis-diagnosed."
***
I am glad to participate in helping track these things!
Where we live (Southern Ontario, just along the Saint Lawrence Seaway)
This has been very noticable to both myself and husband/friends - ever since we moved here 1-1/2 years ago.

We saw a low fat plane with noticable bullbous containers like (shatoga) has described just about a week ago. Weird that you mentioned that one, cause we really took note of it too.
In fact we have observed planes of all kinds it seems.

We see persistant coverage of this area. The sky will be just lit up with
them when the sun reflects accross them - colorful.
We get almost all the different patterns you guys all mention too, the V lately and the regular overal grid, the cotton batton like transformation,
the white sky that results. They do shorter ones all over the place
or other days spaning the horizons, largely in an east west way
it looks like to me. I have seen them reflected by the moon, we hear the planes at night.
We see quite regular - almost every day I bet if I looked - the white/silver long jets
one two three, one two three...
The nearest airport is Ottawa an hours drive due north of me.
Oh ya there are lots of trails visable over that city, it's like they aren't even trying to hide it. I'm in town once a month and have seen this each time.
Definatly they are doing this from passenger planes.

I live close and right between two borders into the states.

We both have exsisting health issues (hep -c) , so I don't know how much of our woes I can blame on the trails. Although,
my hubby has developed respatory problems in the last year or two and we are both fatigued a great deal, muscle weakness and with me joint and body pain, sore eyes, sore even the structure of muscels under my scalp hurts.
Last month I had say, about one week of throwing up everyday (I have a flue shot ) but no fever or other symtom.
I have loss of appitite and am too thin and we both have trouble sleeping.
We are 41 and 45 years old.

These things could be from all sorts of reasons, depression can cause alot of those things too I think. But since we are getting so very much
of the chemtrails here I think it is compounding our problems.

It's odd, when I lived out west I never really noticed this.
I didn't know about it then though. It's amazing what you see when you look up!

Question, have any of you had a successful discusion about this with your family doc.? When I tried to bring it up with ours he said he never heard of that and then he looked at me pretty weird.

***
January 1, 1999, I was in Orlando. Our flight was delayed (over 6 hours) into St. Louis because of the bad weather there. When we finally flew out, the sky was a checker board of contrails over Orlando. By the time I got home at midnight, I had a temp of 106* and the worst back and hip pain of my life. Vomiting too. I thought I was having an arthritis attack. It lasted several days. I thought I'd die. My doc diagnosed it as lupus. (I've not had another episode since.)
I've thought about those contrails. I've thought about maybe bad English beef when I was in the Bahama's...
Who knows?

posted 05-01-2003 06:54 AM            

TITANIUM DIOXIDE
MSDS Number: T3627 --- Effective Date: 02/15/98

--------------------------------------------------------------------------------

1. Product Identification
Synonyms: Titanium (IV) Oxide; C.I. 77891; Titania
CAS No.: 13463-67-7
Molecular Weight: 79.87
Chemical Formula: TiO2
Product Codes:
J.T. Baker: 4162, 4962
Mallinckrodt: 0993

--------------------------------------------------------------------------------

2. Composition/Information on Ingredients

Ingredient CAS No Percent Hazardous
--------------------------------------- ------------ ------- ---------

Titanium Dioxide 13463-67-7 99 - 100% Yes

--------------------------------------------------------------------------------

3. Hazards Identification
Emergency Overview
--------------------------
CAUTION! MAY CAUSE IRRITATION TO SKIN, EYES, AND RESPIRATORY TRACT. MAY AFFECT LUNGS.

J.T. Baker SAF-T-DATA(tm) Ratings (Provided here for your convenience)
-----------------------------------------------------------------------------------------------------------
Health Rating: 3 - moderate
Flammability Rating: 0 - None
Reactivity Rating: 0 - None
Contact Rating: 3 - Moderate
Lab Protective Equip: GOGGLES; LAB COAT
Storage Color Code: Orange (General Storage)
-----------------------------------------------------------------------------------------------------------

Potential Health Effects
----------------------------------

Inhalation:
May cause mild irritation to the respiratory tract.
Ingestion:
Not expected to be a health hazard via ingestion.
Skin Contact:
May cause mild irritation and redness.
Eye Contact:
May cause mild irritation, possible reddening.
Chronic Exposure:
Long-term exposure to titanium dioxide dust may result in mild fibrosis (scarring of the lungs).
Aggravation of Pre-existing Conditions:
Persons with pre-existing lung disease may be more susceptible to the effects of this substance.

--------------------------------------------------------------------------------

4. First Aid Measures
Inhalation:
Remove to fresh air. Get medical attention for any breathing difficulty.
Ingestion:
Not expected to require first aid measures. If large amounts were swallowed, give water to drink and get medical advice.
Skin Contact:
Immediately flush skin with plenty of soap and water for at least 15 minutes. Remove contaminated clothing and shoes. Wash clothing before reuse. Thoroughly clean shoes before reuse. Get medical attention if irritation develops.
Eye Contact:
Immediately flush eyes with plenty of water for at least 15 minutes, lifting upper and lower eyelids occasionally. Get medical attention if irritation persists.

--------------------------------------------------------------------------------

5. Fire Fighting Measures
Fire:
Not considered to be a fire hazard.
Explosion:
Not considered to be an explosion hazard.
Fire Extinguishing Media:
Use any means suitable for extinguishing surrounding fire.
Special Information:
In the event of a fire, wear full protective clothing and NIOSH-approved self-contained breathing apparatus with full facepiece operated in the pressure demand or other positive pressure mode.

--------------------------------------------------------------------------------

6. Accidental Release Measures
Ventilate area of leak or spill. Wear appropriate personal protective equipment as specified in Section 8. Spills: Sweep up and containerize for reclamation or disposal. Vacuuming or wet sweeping may be used to avoid dust dispersal.

--------------------------------------------------------------------------------

7. Handling and Storage
Keep in a tightly closed container, stored in a cool, dry, ventilated area. Protect against physical damage. Containers of this material may be hazardous when empty since they retain product residues (dust, solids); observe all warnings and precautions listed for the product.

--------------------------------------------------------------------------------

8. Exposure Controls/Personal Protection
Airborne Exposure Limits:
Titanium Dioxide:
- OSHA Permissible Exposure Limit (PEL) -
15 mg/m3 (TWA).
- ACGIH Threshold Limit Value (TLV) -
10 mg/m3 (TWA), A4 - Not classifiable as a human carcinogen.
Ventilation System:
A system of local and/or general exhaust is recommended to keep employee exposures below the Airborne Exposure Limits. Local exhaust ventilation is generally preferred because it can control the emissions of the contaminant at its source, preventing dispersion of it into the general work area. Please refer to the ACGIH document, Industrial Ventilation, A Manual of Recommended Practices, most recent edition, for details.
Personal Respirators (NIOSH Approved):
If the exposure limit is exceeded, a half-face dust/mist respirator may be worn for up to ten times the exposure limit or the maximum use concentration specified by the appropriate regulatory agency or respirator supplier, whichever is lowest. A full-face piece dust/mist respirator may be worn up to 50 times the exposure limit, or the maximum use concentration specified by the appropriate regulatory agency, or respirator supplier, whichever is lowest. For emergencies or instances where the exposure levels are not known, use a full-facepiece positive-pressure, air-supplied respirator. WARNING: Air-purifying respirators do not protect workers in oxygen-deficient atmospheres.
Skin Protection:
Wear protective gloves and clean body-covering clothing.
Eye Protection:
Use chemical safety goggles and/or full face shield where dusting or splashing of solutions is possible. Maintain eye wash fountain and quick-drench facilities in work area.

--------------------------------------------------------------------------------

9. Physical and Chemical Properties
Appearance:
White Powder.
Odor:
Odorless.
Solubility:
Insoluble in water.
Specific Gravity:
4.26
pH:
ca. 6 - 7
% Volatiles by volume @ 21C (70F):
0
Boiling Point:
2500 - 3000C (4532 - 5432F)
Melting Point:
1855C (3371F)
Vapor Density (Air=1):
Not applicable.
Vapor Pressure (mm Hg):
Not applicable.
Evaporation Rate (BuAc=1):
No information found.

--------------------------------------------------------------------------------

10. Stability and Reactivity
Stability:
Stable under ordinary conditions of use and storage.
Hazardous Decomposition Products:
No information found.
Hazardous Polymerization:
Will not occur.
Incompatibilities:
For Titanium Dioxide: A violent reaction with lithium occurs around 200C (392F) with a flash of light; the temperature can reach 900C. Violent or incandescent reaction may also occur with other metals such as aluminum, calcium, magnesium, potassium, sodium, and zinc.
Conditions to Avoid:
Dusting and incompatibles.

--------------------------------------------------------------------------------

11. Toxicological Information
Toxicological Data:
No LD50/LC50 information found relating to normal routes of occupational exposure. Investigated as a tumorigen and mutagen.
Carcinogenicity:
NIOSH considers this substance to be a potential occupational carcinogen.

--------\Cancer Lists\------------------------------------------------------
---NTP Carcinogen---
Ingredient Known Anticipated IARC Category
------------------------------------ ----- ----------- -------------
Titanium Dioxide (13463-67-7) Yes Yes 3

--------------------------------------------------------------------------------

15. Regulatory Information
--------\Chemical Inventory Status - Part 1\---------------------------------
Ingredient TSCA EC Japan Australia
----------------------------------------------- ---- --- ----- ---------
Titanium Dioxide (13463-67-7) Yes Yes Yes Yes

--------\Chemical Inventory Status - Part 2\---------------------------------
--Canada--
Ingredient Korea DSL NDSL Phil.
----------------------------------------------- ----- --- ---- -----
Titanium Dioxide (13463-67-7) Yes Yes No No

--------\Federal, State & International Regulations - Part 1\----------------
-SARA 302- ------SARA 313------
Ingredient RQ TPQ List Chemical Catg.
----------------------------------------- --- ----- ---- --------------
Titanium Dioxide (13463-67-7) No No No No

--------\Federal, State & International Regulations - Part 2\----------------
-RCRA- -TSCA-
Ingredient CERCLA 261.33 8(d)
----------------------------------------- ------ ------ ------
Titanium Dioxide (13463-67-7) No No No


Chemical Weapons Convention: No TSCA 12(b): No CDTA: No
SARA 311/312: Acute: Yes Chronic: Yes Fire: No Pressure: No
Reactivity: No (Pure / Solid)

Australian Hazchem Code: No information found.
Poison Schedule: No information found.
WHMIS:
This MSDS has been prepared according to the hazard criteria of the Controlled Products Regulations (CPR) and the MSDS contains all of the information required by the CPR.

--------------------------------------------------------------------------------

posted 05-01-2003 07:03 AM            

9. EFFECTS ON HUMANS

9.1 Case reports

There are many published case reports of adverse health effects
from occupational exposure to quartz. These health effects include
silicosis (acute and chronic) and lung cancer. Case reports of
silicosis and lung cancer are not mentioned further, because these
diseases have been researched in depth in epidemiological studies
(section 9.2).

There are numerous published case reports of several autoimmune
disorders in workers or patients who had been occupationally exposed
to crystalline silica, including quartz dust (NIOSH, forthcoming). The
most frequently noted autoimmune diseases in those reports were
scleroderma, systemic lupus erythematosus (i.e., lupus), rheumatoid
arthritis, autoimmune haemolytic anaemia (Muramatsu et al., 1989), and
dermatomyositis or dermatopolymyositis (Robbins, 1974; Koeger et al.,
1991). Case reports have also described health effects that may be
related to the immunological abnormalities observed in patients with
silicosis, such as chronic renal disease (Saita & Zavaglia, 1951;
Giles et al., 1978; Hauglustaine et al., 1980; Bolton et al., 1981;
Banks et al., 1983; Slavin et al., 1985; Bonnin et al., 1987;
Osorio et al., 1987; Arnalich et al., 1989; Sherson & Jorgensen, 1989;
Dracon et al., 1990; Pouthier et al., 1991; Rispal et al., 1991;
Neyer et al., 1994; Wilke et al., 1996), ataxic sensory neuropathy
(Tokumaru et al., 1990), chronic thyroiditis (Masuda, 1981),
hyperthyroidism (i.e., Graves' disease) (Koeger et al., 1996),
monoclonal gammopathy (Fukata et al., 1983, 1987; Aoki et al., 1988),
and polyarteritis nodosa (Arnalich et al., 1989).

9.2 Epidemiological studies

9.2.1 Silicosis

Most, if not all, of the several hundred epidemiological studies
of exposure to quartz dust are studies of occupational cohorts. The
majority of studies investigated the occurrence of silicosis morbidity
or mortality. These studies have conclusively linked occupational
quartz dust exposure with silicosis. Silicosis (i.e., nodular
pulmonary fibrosis) is a fibrotic lung disease, sometimes
asymptomatic, that is caused by the inhalation and deposition of
respirable crystalline silica particles (i.e., particles <10 µm in
diameter) (Ziskind et al., 1976; IARC, 1987).

A worker may develop one of three types of silicosis, depending
on the airborne concentration of respirable crystalline silica: (1)
chronic silicosis, which usually occurs after 10 or more years of
exposure at relatively low concentrations; (2) accelerated silicosis,
which develops 5-10 years after the first exposure; or (3) acute
silicosis, which develops after exposure to high concentrations of
respirable crystalline silica and results in symptoms within a few

weeks to 4 or 5 years after the initial exposure (Ziskind et al.,
1976; Peters, 1986; NIOSH, 1992a,b, 1996). Acute silicosis is a risk
for workers with a history of high exposures from performing
occupational processes that produce small particles of airborne dust
with a high silica content, such as during sandblasting, rock
drilling, or quartz milling, or any other process with high exposures
to small particles of airborne dust with a high quartz content
(Davis, 1996).

A recent study of 67 paraffin-embedded lung tissue samples from
silicotic patients found a significant linear relationship
(P <0.001) between lung quartz concentration and silicosis severity in
gold miners; although several types of mineral particles were found in
the lungs, quartz was the only significant indicator of silicosis
severity. The silicosis cases included 39 patients without lung cancer
and 28 patients with lung cancer. All of the cases were gold miners in
Canada (Dufresne et al., 1998a,b).

The epidemiological studies of silicosis usually define the
profusion of small opacities present in the disease according to a
standard system used by trained readers and developed by the
International Labour Organization for classification of chest
radiographs of pneumoconioses (ILO, 1980). Each reader assesses the
profusion according to a 12-point scale of severity. Categories 0/-
and 0/0 are the first and second points on the scale and represent a
normal chest radiograph. The third point, category 0/1, represents the
borderline between normality and abnormality, and category 1/0, the
fourth point, represents definite, but slight, abnormality
(Love et al., 1994). The shape (rounded or irregular) and size of the opacities
can also be described by the readers.

The critical studies of chronic silicosis, a progressive disease,
are those occupational epidemiological studies where (1) quantitative
quartz exposure data were available and used for risk analysis,
(2) exposure-response relationships were investigated, or (3) the
exposure-response relationships were documented with sufficient detail
for a health effects benchmark, including (4) application of data to
mathematical models that predicted silicosis prevalence at increasing
concentrations of cumulative quartz exposure. (The predicted
prevalences reported in the studies are discussed in section 11.1.3.)
Studies that selected workers from a broad spectrum of occupations and
included many workers that were exposed to different combinations of
various minerals, such as studies of "dusty trades" workers
(i.e., Rice et al., 1986), were excluded from consideration for risk
assessment of quartz and silicosis. Epidemiological studies that
provided evidence of an exposure-response relationship for silica and
silicosis based on other kinds of exposure data (e.g., there is a
positive relationship between development of chronic silicosis and
duration of exposure) have been reviewed elsewhere (WHO, 1986;
Goldsmith, 1994; Hughes, 1995; Rice & Stayner, 1995; Seaton, 1995;
Steenland & Brown, 1995a; Davis, 1996; US EPA, 1996).

The two critical cross-sectional studies (i.e., Kreiss & Zhen,
1996; Rosenman et al., 1996 -- see Table 6) found that the prevalence
of radiographic silicosis (ILO category >1/0 or >1/1) was
dose-related. That is, the prevalence of radiographic silicosis
increased with average silica dust exposure, cumulative quartz
exposure, duration of employment, or all of these measures. The actual
prevalences varied greatly among the studies, and conclusions
concerning quartz dust concentrations that may or may not induce
silicosis cannot be drawn from simple "eyeball" analysis of the
prevalences in the following two worker populations:

* Kreiss & Zhen (1996) conducted a community-based random sample
survey of 134 male residents at least 40 years old, living in a
hardrock (i.e., molybdenum, lead, zinc, and gold) mining town in
Colorado, USA. Of the 134 residents, 100 were silica-exposed
hardrock miners (including 32 silicosis cases) and 34 were
community "controls" without occupational dust exposure. Nearly
all (97%) of the dust-exposed subjects were 20 years since first
exposure. The estimated crystalline silica content (polymorph not
reported) of the total dust was 12.3%. Exposure was assessed with
information from occupational histories, gravimetric dust
exposure data from 1974-1982, and a cumulative silica exposure
index. Pre-1974 exposure estimates were based on job-specific
gravimetric data collected after 1974. Exposures were also
estimated for mines where no exposure data were available (17.1%
of person-years of follow-up). Thirty-two per cent of the 100
dust-exposed subjects had silicosis (defined as radiological
profusion of small opacities of ILO category >1/0). Prevalence
of silicosis was related to average silica dust exposure. Among
the 94 dust-exposed subjects with data on cumulative and average
dust exposures, those subjects with average silica exposure
<0.05 mg/m3 had 10% prevalence of silicosis; subjects with
>0.05-0.10 mg/m3 had a prevalence of 22.5%; subjects with
greater than 0.10 mg/m3 average silica exposure had a silicosis
prevalence of 48.6% (P = 0.01). (See Table 6 for predicted
prevalences when silicosis was defined as radiological profusion
of small opacities of ILO category >1/1.) It is not known
whether the small sample of 134 residents was representative of
all miners or if the exposure estimates for mines where no
exposure data were available (17.1% of person-years of follow-up)
were representative.

* Rosenman et al. (1996) conducted a cross-sectional study in 1991
of 549 current, 497 retired, and 26 current salaried workers that
were former production workers in a US grey iron foundry that
produced automotive engine blocks (total workers = 1072).
Twenty-eight cases (2.9%) of silicosis, defined as rounded
opacities >ILO category 1/0, were identified by at least two
of three "B" readers of a total of 952 chest radiographs. More
than half (18/28) of the cases were found in retired workers.
Silicosis prevalence was positively related to mean silica (i.e.,
quartz) exposure (P < 0.0001). Of the workers with mean quartz

exposure less than 0.05 mg/m3, 0.8% had silicosis, while 6.3%
of foundry workers with mean quartz exposure greater than 0.45
mg/m3 had silicosis. Silicosis prevalence also increased with
years of employment at the foundry, cumulative silica exposure,
work area within the foundry, and cigarette smoking (i.e., smoker
vs. non-smoker). Exposure estimates were derived from conversions
of "early silica exposure data" collected by impingers. Quartz
content of total dust was not reported. Weighted total dust
exposure from impinger data was converted to an estimate of
silica exposure in mass units (mg/m3) by multiplying it by the
average percentage of quartz in bulk samples.

Results of cohort studies of gold miners in South Africa, Canada,
and the USA (see Table 7) also demonstrated an exposure-response
relationship for radiographic silicosis (US EPA, 1996):

* A cohort study was conducted of 2235 white South African
underground gold miners, 45-54 years old at the time of medical
examination in 1968-1971, who started working after 1938, worked
>10 years, and were followed until 1991 (Hnizdo &
Sluis-Cremer, 1993). More than 300 (n = 313) of the 2235 miners
were followed to the time when radiological signs developed, 658
miners were followed up to death, and 1264 miners were followed
to the year of the most recent radiograph. Radiographs were read
blindly by two independent readers. Silicosis was defined as the
presence of rounded opacities of ILO category >1/1.
Radiographs were read blindly by two readers initially, then one
reader was chosen because his readings more closely matched the
autopsy data. Mean respirable dust concentrations, after heat and
acid treatment, in milligrams per cubic metre per shift were
calculated for nine gold mining occupations. The concentrations
were based on a study of shift-long dust exposure that measured
the surface area of the respirable mine dust and the number of
respirable particles (i.e., incombustible and acid-insoluble dust
particles) per cubic metre in a random sample of 20 South African
gold mines (Beadle, 1965, 1971). After heat and acid treatment,
the respirable dust in South African gold mines was found to
contain about 30% quartz (Beadle & Bradley, 1970). Cumulative
dust exposure for the miners was calculated in milligrams per
cubic metre-year by using data for mean mass respirable dust
concentrations for the nine occupational categories, the average
number of hours underground, and the number of dusty 8-h shifts.

Of the 2235 miners studied by Hnizdo & Sluis-Cremer (1993),
313 developed radiologically diagnosed silicosis (rounded
opacities with profusion of ILO category >1/1) during the
follow-up period (i.e., 1968-1971 to 1991). The onset of
silicosis occurred after an average (i.e., mean) of 27 years of

Table 6: Predicted prevalence of silicosis (ILO category >1/1)
following exposure to respirable quartz dust based on modelling of cumulative exposure
at mean concentrations of 0.05 or 0.10 mg/m3 over a 45-year working lifetime.

Cross-sectional study Mean concentration of Predicted prevalence of Cohort's mean time Cohort's maximum time
and cohort respirable quartz dust silicosis, ILO category since first quartz since first quartz
(mg/m3) >1/1 (cases per exposure (years) exposure (years)
100 workers)

Kreiss & Zhen, 1996 0.05 approx. 30a silicotic miners: silicotic miners:
41.6 66
100 US hardrock 0.10 approx. 90a non-silicotic non-silicotic
miners and 34 miners: 33.5 miners: 68
community controls

Rosenman et al., 0.05 2b,c 28 >30
1996
1072 US grey 0.10 3b,c
iron foundry workers

a Based on cumulative silica exposure model with 10 years of post-employment follow-up.
b ILO category >1/0.
c Based on a 40-year working lifetime and controlling for pack-years of cigarette smoking, race,
and silica exposure other than in the foundry under study.

Table 7: Predicted number of silicosis cases (ILO category >1/1) following exposure to respirable
quartz dust based on modelling of cumulative exposure at mean concentrations of 0.05 or 0.10 mg/m3
over a 45-year working lifetime.

Cohort study Mean concentration of Silicosis cases, Mean time since first Maximum time since
and population respirable quartz ILO category >1/1, quartz exposure (years) first quartz exposure
dust (mg/m3) per 100 workers (years)

Hnizdo & 0.05 13a silicotic miners: 36 silicotic miners: 50
Sluis-Cremer, 1993
2235 South African 0.10 approx. 70
gold miners

Muir et al., 0.05 0.09-0.62a,b 18 silicotic miners: 38
1989a,b;
Muir, 1991
2109 Canadian
gold and
uranium miners

Steenland & 0.05 10c 37 73d
Brown, 1995a
3330 US gold 0.09 47c
miners

a Estimate was reported in Rice & Stayner (1995).
b No post-employment follow-up and no retired miners included. The range includes five estimates
(one for each reader).
c The predicted number of silicosis cases does not account for effects of age or calendar time
(K. Steenland, personal communication, 1997).
d K. Steenland, personal communication, 1998.

net service, at a mean age of 56 years. For more than half of the
miners (n = 178; 57%), the onset occurred an average of
7.4 years (standard deviation 5.5; range 0.1-25 years) after
their employment at the mines, at 59 years of age (range
44-74 years). For the other miners (n = 135; 43%), the onset
of silicosis occurred while they were still mining, at 51 years
of age (range 39-61 years). These results show that the majority
of the cases occurred in miners who were no longer employed at
the mine and who were at least 50 years old
(Hnizdo & Sluis-Cremer, 1993).

* Muir and colleagues conducted a study of 2109 current Ontario
miners from 21 gold and uranium mines who started working and
worked more than 5 years between 1940 and 1959 and were followed
to 1982 or to the end of their dust exposure, whichever came
first (Muir et al., 1989a,b; Muir, 1991). Any uranium miner with
more than 2 weeks of exposure was also included (Muir et al.,
1989a). The quartz content of respirable gold mine dust was 6.0%,
and that of uranium mine dust was 8.4%. Retired and former miners
were not included in the study. Sources of data for this study
were full-sized annual chest radiographs taken for all miners
after 1927 and periodic (pre-1959) and semi-annual mine dust
measurements obtained with a konimeter (which is an instantaneous
dust sampler that measures the number of particles per unit
volume of air; Verma et al., 1989). Konimeter dust measurements
taken from 1940 to 1952 were expressed in particles per cubic
centimetre of air (ppcc). Verma et al. (1989) initiated an
extensive, side-by-side comparison of the konimetric and
gravimetric (i.e., milligrams of silica per cubic metre) sampling
to derive a konimetric/gravimetric silica conversion curve. A
total of 2360 filter (i.e., nylon cyclone-filter assembly in a
constant-flow pump) samples and 90 000 konimeter samples were
taken in a 2-year period in two gold and uranium mines, in
existing conditions as well as in an experimental simulation of
the high-dust conditions of the past caused by dry drilling
(Verma et al., 1989). The results of the conversion relationship
were non-linear and may have reflected the limitations of the
konimeter in measuring high dust (i.e., high count)
concentrations and the limitations of the gravimetric sampler in
measuring low dust concentrations. There were different
relationships for the gold and uranium mines, possibly because of
the different fractional silica concentrations in the host rock.
The conversion of the historical konimeter counts to gravimetric
respirable silica equivalents was used to derive a cumulative
respirable silica dose for each miner based on the miner's
respirable silica dose for each year, mine, and task in his work
history (Verma et al., 1989).

Thirty-two of the 2109 hardrock miners studied by Muir and
colleagues were considered by at least one of five readers to
have silicosis (small, rounded opacities with profusion of ILO
category >1/1). However, the results differed among the five
readers and "complicated the analysis" (Muir et al., 1989b). One
of the five readers identified only seven cases of silicosis

(Muir et al., 1989b). The results were presented by individual
reader and by consensus. A consensus of all of the five readers
with respect to identification of silicosis was reached on only
six cases (Muir et al., 1989b). Average respirable quartz dust
exposure for the cases was not reported.

* A cohort study of 3330 white male underground gold miners from
South Dakota employed for at least 1 year between 1940 and 1965
and followed through 1990 found 170 cases of silicosis (128 cases
were identified on death certificates, 29 cases were found during
X-ray surveys of workers conducted in 1960 and 1976, and 13 cases
were identified on both X-ray and death certificate). Cases were
defined as (1) an underlying or contributing cause of death of
silicosis, silico-tuberculosis, respiratory tuberculosis, or
pneumoconiosis, and/or (2) ILO category >1/1 silicosis
identified in the 1976 radiographic survey or "small opacities"
or "large opacities" identified in the 1960 radiographic survey
(Steenland & Brown, 1995a). The miners were exposed to a median
quartz level of 0.05 mg/m3 (0.15 mg/m3 for workers hired prior
to 1930). The average length of follow-up was 37 years, and the
average length of employment underground was 9 years. Quartz
exposure was estimated by converting dust particle counts to
gravimetric measurements (i.e., mg/m3), based on an estimate of
13% quartz content of total dust. A job-exposure matrix was
created to estimate dust exposures for each job over time, then
average dust exposures for the job categories were calculated
using existing measurements for each year from 1937 to 1975. The
estimated daily dust exposures (constant over each year) were
weighted to account for daily time spent underground. Summation
of the estimated daily dust levels over time provided an estimate
of cumulative quartz exposure (Steenland & Brown, 1995a). The
risk of silicosis was less than 1% for miners with a cumulative
exposure less than 0.5 mg/m3-years. The risk increased to 68-84%
for the highest cumulative exposure category (i.e.,
4 mg/m3-years) (Steenland & Brown, 1995a). Silicosis risk
estimates could have been affected by (1) combining silicosis
deaths with silicosis cases detected by cross-sectional
radiographic surveys, (2) differences in quartz content of dust
in early years, and (3) lack of dust measurements before 1937.

A cohort study of a subcohort of the South Dakota gold
miners described above analysed cases of silicosis that were
reported as the underlying cause of death on the death
certificates. Forty cases of silicosis, as well as 49 cases of
tuberculosis, were ascertained among the 1321 miners employed for
at least 21 years and followed through 1973. There was a linear
trend in risk of about 2.4% for each 0.1 mg/m3 of silica
exposure. However, this study does not meet the criteria for a
critical study because risk by cumulative quartz exposure was not
calculated (McDonald & Oakes, 1984).

In the five critical studies described above, the number of cases
identified depended upon the definition of silicosis (radiographic
category and whether irregular opacities were included), the quality
of the evaluation of the chest radiographs (e.g., number and training
of readers), the duration of dust exposure, and the duration of
follow-up after the end of exposure. Interstudy variation exists for
each of these factors. In addition, exposure assessments in these
studies were accompanied by uncertainties, such as the use of
conversion equations (i.e., converting particle count data to mass
concentrations; application of equations from one industry to a
different industry) and estimation of quartz content of the dust. It
is not uncommon for epidemiological studies to lack characterization
of the source and properties of the mineral dusts collected in the
workplace (Mossman & Churg, 1998). Nevertheless, the critical studies
found an exposure-response relationship for respirable quartz dust
that, when modelled, predicts the occurrence of silicosis cases in
various industries at exposures close to regulatory levels.

posted 05-01-2003 10:49 AM            

let's see a "physical" real already built c. generator....

then on a plane...

then in use...

then let's see the enormous fleet that sprays the world...

how about we meet a few of the pilots, ground crew and mantinence...

damn that should be easy with all the folks involved eh shitoga ?

common sense is a trait left out of the liberal gene pool...

posted 05-01-2003 11:59 AM            

Ok, sorry for venturing into Dan Rockwell's world for a second there..

posted 05-01-2003 11:05 PM            

A cut & paste comparable to Mech's style.

Quite good!

See how facts argue for themselves.

Point well made that:
The old and weak suffer most from either
West Nile, chemtrails and/or SARS

with similar symptoms yet....

Point well made!

Makes insults seem even more childish
by comparison to yours & Mech's posted facts.

posted 05-02-2003 12:34 AM            

when has the old and weak not suffer more ?