Discretizations

 "'Hunches', even if held by experts, are not scientific knowledge."

Banning plastic grocery bags might be a very bad idea.

There's no such thing as negligent failure to generate the same hypothesis as plaintiff's future experts.

There's a very slight increased risk of lung cancer among Carolina chrysotile textile workers with 100 f-yr/ml exposure.

Apparently, the Restatement (Third) of Torts, Liability for Physical and Emotional harm, section 7's exception permitting no-duty rules when "relatively clear, categorical, bright-line rules of law" can be promulgated is big enough to drive the very big take-home truck through it. We predict dyspepsia for Michael Green. See Mary Campbell v. The Ford Motor Company.

Discretizations

Discretizations

The conjunction paradox isn't one and doesn't require new standards of proof; rather, it's evidence that the asymmetry in the law markedly favors false positives, whatever some may say.

Cancer-causing H. pylori might find its way into you by hitching a ride in food borne yeasts.

Blame for obesity: BPA vs BUG.

The evidence that hormone replacement therapy "causes" breast cancer isn't as strong as you think.

Occupational exposure to animals: evidence for a causal link with cancer mounts.

Discretizations

Erionite in North Dakota

Mesothelioma plaintiff lawyers will no longer be able to mockingly ask their clients "Have you ever been to Cappadocia, Turkey?" That's because it turns out there's plenty of erionite in the USA. For more info see, just  published in the Proceedings of the National Academy of Sciences of the United States of America: "Erionite Exposure in North Dakota and Turkish Villages With Mesothelioma".

Discretizations

How Reliable Are Exposure Estimate Techniques?

This month's Journal of Occupational and Environmental Hygiene has several interesting articles. If you're looking for confirmation of the worry that expert subjective or quasi-quantitative (e.g. task based) exposure estimation techniques don't produce anything that has much to do with reality see:

"Evaluation and Comparison of Three Exposure Assessment Techniques"

If you want an estimate of benzene exposure above 1 ppm from mineral spirits containing less than 0.1% benzene wt/wt see:

"Estimating Airborne Benzene Exposures from Air Monitoring Data for Mineral Spirits"

If you wonder why historical data on asbestos exposures from joint compound don't jibe with data from recent efforts to measure exposures using recreated asbestos-containing joint compound from old formulae see:

"Potential Artifacts Associated with Historical Preparation of Joint Compound Samples and Reported Airborne Asbestos Concentrations."

Finally, if you want to know what variables influence dust in the breating zone of drywall sanders see:

"Factors Influeincing Dust Exposure: Finishing Activities in Drywall Construction"

Always remember, what you see depends on how you look as much as where you look. 

Does Recall Bias Explain Past Associations Between Pesticides and Parkinson's

How do people's memories of pesticide exposures correlate with industrial hygiene estimates of those exposures? Not so well. In fact it's pretty clear that a lot of people with Parkinson's assume that chemicals caused their illness and so are primed to remember past high exposures that had not in fact occurred. For a well done paper showing no association between pesticides and Parkinson's plus a great discussion of recall bias see: "Pesticide Exposure and Risk of Parkinson's Disease - A Population-Based Case-Control Study Evaluating the Potential for Recall Bias".

Those looking for the real cause of the increase in risk of Parkinson's among those involved in farming should pay attention to the endotoxin discussion. I'll check the studies that show endotoxin may protect against lung cancer in cotton textile workers to see if there's any hint of a Parkinson's excess and report back.

Welding and Cardiovascular Disease

When it comes to cholesterol the thing to worry about is too little HDL. Your total cholesterol level can be high and your LDL can be high but if your HDL is up there you're swimming in the shallow end of the risk pool. That's what makes "Acute Decrease in HDL Cholesterol Associated With Exposure to Welding Fumes" so interesting.

The finding of a large decrease in HDL without effect upon other lipids following exposure to pm2.5 in welding fumes provides, if replicated, a biological mechanism for some of the maladies laid at the feet of pm2.5. Low levels of HDL lead to inflammation and chronic inflammation leads to a variety of illnesses like hardening of the arteries.

"A Global Toxic Emergency"?

The Story of Stuff people have now released "The Story of Electronics". In it they proclaim "a global toxic emergency" declaring that Silicon Valley is "one of the most poisoned communities in the U.S." and repeat an old canard about the alleged toxic perils of working in high tech manufacturing in general and clean rooms in particular. As is typical of such pieces even the most modern facilities are portrayed as little better than the Triangle Shirtwaist Factory.

Coinciding with the video's release comes the publication of its antidote. In "Cancer Mortality Among US Workers Employed in Semiconductor Wafer Fabrication" the health outcomes of 100,081 semiconductor workers employed between 1968 and 2001 were examined and analyzed. Compared to people in the general population of similar age, gender and race their overall risk of death from all causes combined was cut in half and their risk of dying of any sort of cancer was just three quarters that of other people. As for cancers of the blood referenced in "The Story of Electronics", there's nothing to worry about in that regard either.

The paper concludes "Work in the US semiconductor industry, including semiconductor wafer fabrication in cleanrooms, was not associated with increased cancer mortality overall or mortality from any specific form of cancer."

The exposure assessment for these same workers was also just published and can be found in "Exposure Assessment Among US Workers Employed in Semiconductor Wafer Fabrication".

Chronic High Noise Exposure and Coronary Heart Disease: A Strong and Consistent Association

In "Exposure to Occupational Noise and Cardiovascular Disease in the United States: the National Health and Nutrition Examination Survey 1999 - 2004"  researchers report a doubling or tripling of the risk for coronary heart disease among workers chronically exposed to high occupational noise. Meanwhile, other studies are showing that men subjected to aircraft noise from nearby airports and overflights face an increased risk of hypertension. See "Aircraft Noise and Incidence of Hypertension-Gender Specific Effects", "Exposure-Response Relationship of the Association Between Aircraft Noise and the Risk of Hypertension" and, for evidence that helicopter noise is most strongly associated with an increased risk of hypertension see "The Effects of Chronic Exposure to Aircraft Noise on the Prevalence of Hypertension".

Here are a few Power Point presentations (.pdf format) from the WHO on the topic of the health impacts of chronic noise exposure:

"Noise and Children"

"Quantifying Burden of Disease from Environmental Noise"

"Health Effects of Noise"

Twenty Suspected Carcinogens

The American Cancer Society is calling for new research to settle the issue of whether or not twenty different agents do indeed cause the types of cancer in which they've been implicated. The twenty are:

(1) Lead and lead compounds; (2) indium phosphide (used in many flat screen TVs); (3) cobalt with tungsten carbide; titanium dioxide; (4) welding fumes; (5) refractory ceramic fibers; (6) diesel exhaust; (7) carbon black; (8) styrene oxide and styrene; (9) propylene oxide; (10) formaldehyde (does it cause leukemia?); (11) acetaldehyde; (12) formaldehyde; (13) methylene chloride; (14) trichloroethylene; (15) tetrachloroethylene; (16) chloroform; (17) PCBs; (18) DEHP (a phthalate); (19) atrazine (a herbicide and the subject of a coordinated attack by various activists groups resulting in a new EPA review); and, (20) shift work (the presumed exposure being "light at night" leading to a disruption of circadian rhythms and the most commonly associated malignancy being breast cancer).

You can find the press release here: Report Outlines Knowledge Gaps for 20 Suspected Carcinogens; and you can find the IARC report summarizing past rationale for assigning these suspected carcinogens to groups 2A - 3, the new evidence forming the basis for the recommendation that the status be updated and the sorts of epidemiological and mechanistic studies necessary to answer the question of whether they ought to be added to the list of 107 Group 1 agents known to be carcinogenic to humans, here: Identification of Research Needs to Resolve the Carcinogenicity of High-Priority IARC Carcinogens.

Clostridium Difficile in the News

Can C. difficile be spread through the air? What does C. difficile have to do with COPD? How should physicians treat the new and especially virulent strain of C. difficile? At what temperature should you cook ground meat to kill C. difficile and its spores? Do alcohol-based gels kill it? Why do antacids administered in hospital increase the risk of infection? Are there new antibiotics that work against C. difficile?

Click on the links for a sense of current thinking on these issues.

An Unusual Benzene/MDS Opinion

In Quillen v. Safety-Kleen Systems, Inc., 2010 WL 2044508 (E.D.Ky.) the court determined that plaintiff's expert, Dr. George Rogers, could properly attribute a case of myelodysplastic syndrome (MDS) to benzene by doing a differential diagnosis. That some courts have taken to using differential diagnosis to identify the root cause of say splenomegaly rather than to distinguish histoplasmosis induced splenomegaly from Hodgkin's disease induced splenomegaly would likely set many physicians' eyes rolling.  Yet, that's apparently what the 6th Circuit said in Hardyman v. Norfolk & Western Railway Co., 243 F.3d255 (6th Cir. 2001) and thus the thinking by the Quillen court.

The point of doing a differential diagnosis, of course, is to rule out possible causes until just one is left - it's a process of elimination. But just because every other cause of splenomegaly has been ruled out in the case of a male patient that doesn't mean that it makes sense to conclude that the cause must be the remaining possibility - a metastatic ovarian cancer. To be considered for elimination in the first place the putative cause has to be one that makes sense. In Quillen though there was no effort to demonstrate that plaintiff's experience with benzene was the sort that would make benzene a reasonably plausible cause of his MDS.

Finally, please ponder the following. In response to the defendant's objection that plaintiff's expert had not ruled out ionizing radiation  the court wrote: "Defendant points to nothing in the record demonstrating that Quillen was ever exposed to a statistically significant amount of such radiation." Somewhere an epidemiologist just fell out of her chair.

Occupational Exposure to Endotoxins: A Good Thing?

In the newest edition of the journal Cancer Causes and Control you'll find a paper titled "Endotoxin Exposure and Lung Cancer Risk: A Systematic Review and Meta-Analysis of the Published Literature on Agriculture and Cotton Textile Workers". The authors examined 28 studies of workers occupationally exposed to high levels of endotoxins and their risk of developing lung cancer. Previous studies had suggested acute and chronic lung conditions could be caused by endotoxins.

Interestingly, endotoxin exposure was consistently associated with a large and statistically significant decrease in lung cancer. Furthermore, the protective effect was strengthened as dose was increased.

Also this month, in Cancer Epidemiology, Biomarkers & Prevention, you'll find "Lower Risk of Lung Cancer After Multiple Pneumonia Diagnoses". It turns out that getting pneumonia three or more times is even better than high exposure to endotoxins if you want to avoid lung cancer.

What is it about these biological challenges to the lung that leads to significant anti-lung cancer protective effect? It's anyone's guess but perhaps keeping your immune system tuned up is part of the answer.

No Association Between Industrial-Grade Talc and Mesothelioma

A new review of available toxicological, mineralogical and epidemiological data pertaining to talc mined in northern New York by R T Vanderbilt shows no support for the claim that exposure to it causes mesothelioma. See: "Industrial-Grade Talc Exposure and the Risk of Mesothelioma" just published in Critical Reviews in Toxicology.

Chemical Safety Board Issues Hot Work Safety Bulletin

The Chemical Safety Board (CSB) has developed recommendations following its investigation of a triple fatality accident that occurred when welding on a tank containing hydrogen, due to bacteria digesting organic matter within, sparked an explosion. The seven key lessons learned from CSB's recent hot work accidents are:

1. Use alternatives when possible

2. Analyze the hazards

3. Monitor the atmosphere even in areas where a flammable atmosphere is not anticipated

4. Test the area whenever work is done near other tanks containing flammable liquids or gases.

5. Use written permits (Editorial comment: there are places where Hot Work permits aren't used? In 2010?

6. Train thoroughly

7. Supervise contractors - Provide safety supervision for outside contractors conducting hot work. Inform contractors about site-specific hazards including the presence of flammable materials.

CSB notes that while OSHA does not explicitly require the use of a combustible gas detector it is good practice to do so. The American Petroleum Institute and FM Global both have long stressed the need for combustible gas detectors to prevent fires and explosions.

As an aside, your writer learned, shortly after being admitted to the practice of law in 1986, that the oil and chemical companies here in Southeast Texas were using such gas detectors by the 1960s. In fact, in the case of one of my clients, a major refiner, its very first recorded fatality occurred in the 1930s when a man was killed by a manhole cover thrown through the air as the result of an explosion caused by hot work near a sewer. After its investigation the company paid to have someone develop a gas detector and it instituted a hot work permitting system more than 60 years ago.

An Explanation for the Quebec/South Carolina Chrysotile Conundrum?

Why is there such a disparity between health outcomes of the workers who mined chrysotile and the textile workers who used it? In "Comparing Milled Fiber, Quebec Ore, and Textile Factory Dust: Has Another Piece of the Asbestos Puzzle Fallen into Place?" Berman reports that the dusts encountered at the facilities vary in two important ways. First, whether assessed by PCM or TEM, samples revealed that mine and mill dusts contain only 67% asbestos. On the other hand, typical feedstock for the textile facility was 100% asbestos. Second, the feedstock asbestos fibers were significantly longer than those typically encountered by workers exposed to mined or even refined asbestos.

Thus, for a given quantity of dust textile workers would have an approximately 50% greater exposure to asbestos and that exposure, on a fiber per fiber basis, would be significantly riskier. The author also suggests a method for reconstructing past exposures which would more accurately estimate the risk posed by each of those exposures.

To How Much Manganese Are Welders Exposed?

In "Manganese, Iron, and Total Particulate Exposures to Welders" the authors analyzed multiple sets of data in an attempt to characterize exposures generated by welding. They conclude that manganese exposures are likely often above the current TLV of 0.2 mg/cubic meter.

Significantly, they also report strong and consistent correlations between levels of manganese, iron and total particulate that, they suggest, would allow the extrapolation of manganese exposure where only data on say iron exposure is available. Expect to see this approach used to demonstrate high exposures where none were seen before.

Using Proteins to Count and Differentiate Asbestos Fibers

Suggested as an accurate and convenient alternative to the PCM method of estimating airborne concentrations of asbestos fibers, Japanese researchers have devised a method of using different E. coli proteins  to selectively bind to either amphiboles or chrysotile. The resulting mix of amphiboles and chrysotile fibers can then be more precisely counted and differentiated.

The number of methods available to estimate asbestos exposure, each generating a different answer, continues to grow; further muddying the already murky waters of extrapolating past exposures from modern methods.

DTSC: Green Chemistry Initiative

The initiative to make products with safer chemicals is gaining momentum and media attention. DTSC Acting Director Maziar Movassaghi explains in the linked article and video that green chemistry is a new type of environmental protection, which results in everyday products that contain less toxic chemicals. Movassaghi goes on to explain that the rules are currently being drafted; however, some companies are already embracing the change, as the wave of the future.
 

Improving the Consistency and Effectiveness of Hazard Communication

The United Nations Globally Harmonized System (GHS) of Classification and Labelling of Chemicals was developed by a number of countries, including the United States, to address inconsistencies in hazard classification and communications. 

OSHA is adopting the GHS approach and believes it will increase workplace safety, facilitate international trade in chemicals, and generate cost savings from production efficiencies for firms that manufacture and use hazardous chemicals.

Forsterite: Less DNA Damage Than Chrysotile

If a chronic inflammatory process is behind asbestos' mayhem, then forsterite, the product of asbestos heated to very high temperatures, is likely to be far less harmful than even chrysotile.

See article.
 

How Safe is Your Drinking Water?

Helicobacter pylori has been identified as a causative agent in cancers that are often the subject of mass tort cases such as lymphoma, stomach and colon cancer.  Though the route of transmission of helicobacter pylori is unknown it's believed that the infection is acquired early in life through drinking water.   

Here's a paper that will be presented at a conference on water and public health to be held in Philadelphia, Pennsylvania this November by the American Public Health Association that discusses how helicobacter pylori might catch a ride on amoebas to infect our water supply.  Or if you want to worry about bladder cancer from exposure to arsenic in the water supply then you might find this link of interest.  The full program can be found here.

Two other papers you might find of interest on this cancer-causing agent via the public water supply can be found here and here.

Chrysotile Mining Worldwide Is Back Up To 1960 Levels

According to this rather expensive article published in The Lancet, despite a ban in 40 countries and dramatically reduced consumption levels in other industrialized countries like the U.S., 2.2 million metric tonnes of chrysotile is still being mined and used annually with much of it going into projects in China and India. For good or ill a laboratory for studying the effects of white asbestos exposure in humans has been established.

Lead Take-Home Poisonings

The CDC has reported on six cases of children exposed to lead while in their car seats who developed lead poisoning.  The lead was not in the car seats but rather tracked into the vehicles by the husbands or boyfriends of the children's' mothers.  The contamination had come from metal recycling or paint removal job sites.  Hat tip:  Dr. Buttery's Public Health BLOG.

Childhood Lead Poisoning Associated with Lead Dust Contamination of Family Vehicles and Child Safety Seats.

Lung disease including deaths among Chinese paint workers

Reuters is reporting on an outbreak of lung disease among workers at a Chinese paint factory potentially due to exposure to nanoparticles.

Industrial Hygiene Survey, Navy Yard, New York, NY 1943

Dr. Leonard J. Goldwater, whom I was fortunate to get to know and with whom I corresponded for several years after finding him alive and well after an expert witness in one of my cases testified that "Dr. Goldwater, if he were alive today, would tell you that by 1939 it was known that benzene caused leukemia", gave me this document out of his trove of articles and letters that he'd collected over a long and especially distinguished career. 

In subsequent posts I'll relate some of his stories ranging from his testimony at the 1936 Gauley Bridge Disaster hearings before the U.S. Congress, to his work on benzene and blood dyscrasias in the late 1930's and early 1940's, through his extensive work on mercury and to his deposition testimony in the 1980's about the history of the knowledge of asbestos all gleaned from his work with the New York Department of Health, as Industrial Health Officer responsible for Navy shipyards during World War II and as a researcher and academic.