Pyrex, Soda Lime, Borosilicate, and the Environment

I noted in an earlier post that STATS was looking into the environmental impact of making Pyrex with soda lime glass instead of boroscilicate glass. The switch has been blamed for a spate of “explosions” as Pyrex made with soda lime has a greater rate of thermal expansion than Pyrex made with borosilicate: if you put a hot dish on a cold, wet surface, it could shatter, warns the manufacturer.

STATS spoke with Phil Ross, an independent consultant to the glass industry, whose clients have included World Kitchen, which makes Pyrex in the United States). He said the industry as a whole switched from borosilicate started in the 1980s for a variety of reasons, including the fact that soda lime was easier to melt and work with (fewer deformities in the glass). But one of the major reasons for moving to soda lime was environmental compliance: borosilicate glass produces far more emissions from a glass furnace , accounting, in part, for the presence of boric acid in the water and soil. And it was not economical for companies to install multi-million dollar filter systems.

Add to that, Ross says, the fact that furnaces have a longer lifespan if you use soda lime, and require less energy (15 to 20% lower than for borosilicate), and the economics for the switch were compelling.

These aspects led the entire glass bakeware industry in the U.S. to switch to soda lime starting in the 1980s (borosilicate is still used for laboratory glassware). Given the length of time soda lime has been used in bakeware multiplied by the number of times an individual piece has been used in a kitchen, the numbers cited by CBS and other local television news outlets for a trend in exploding dishes are tiny. If there was a substantial flaw in soda lime bakeware, or if heat tempering was insufficient, it’s reasonable to wonder why breakage isn’t more common. Literally, hundreds of millions of dishes are being used multiple times a week without apparent incident.

Does Pyrex “Explode” Because the Manufacturer Changed the Mix? CBS Chicago’s Epic Investigation Continues

Ratings-challenged Channel 2 in Chicago delivered part three of its investigation into “exploding” Pyrex last night (see here and here for reviews of parts one and two).

It breaks down into the claim by CBS’s experts (one of whom is acting as an expert witness in a lawsuit against World Kitchen for a product other than Pyrex) that the glass Pyrex is now made from (heat-treated soda lime) isn’t able to withstand temperature changes in the way the old Pyrex (borosilicate glass) could.

True. The coefficient of thermal expansion for borosilicate glass is 35 x 10 to the power of minus seven, inch per inch per degree centigrade, while that of heat-strengthened soda lime glass is 85 x 10 to the power of minus seven, inch per inch per degree centigrade. This means soda lime glass has three times the thermal expansion of borosilicate glass, which accounts for greater dynamic breaking when a hot soda lime dish encounters a cold, wet surface – and why the manufacturer warns not to expose dishes to such temperature conditions. CBS 2’s experts claim that U.S. made Pyrex isn’t “tempered” enough; World Kitchen says their product is.

Soda lime glass is cheaper and easier to make than borosilicate glass (which is still used in European-manufactured Pyrex), and, of course, that raises the specter of a manufacturer cutting corners for the sake of profit; on the other hand, manufacturing soda lime appears to be more environmentally friendly in terms of industrial emissions (we’re chasing down the data on that one).

But here’s what CBS 2 didn’t tell viewers: Heat-treated soda lime glass has nearly double the mechanical strength of borosilicate glass. Both soda lime and borosilicate glass can withstand pressures of roughly 6,500lbs per square inch before breaking; but heat-strengthening soda lime can add another six to seven thousand pounds per square inch of mechanical strength. This means that strengthened (sometimes call tempered) soda lime bakeware is less likely to break if you hit it or drop it.

As this is the most common way people injure themselves from glass bakeware, isn’t this aspect something which CBS should have mentioned? Think about the emergency room data. If you query the Consumer Product Safety Commission’s emergency room database of product related injuries (enter code 461), you’ll find that the most common injuries from glass bakeware are lacerations that occur after a dish has been dropped. Injuries from a thermal downshock “explosion” are much more rare. In fact, based on emergency room data for 2005, you had just a 1 in 3,706, 338 chance of sustaining a non-fatal injury from glass bakeware that didn’t shatter from mechanical breakage.

The injuries – two burns and a cut foot – reported by CBS 2 are unfortunate, and their cause alarming. The 300 reports of similar explosive accidents require much more systematic evaluation before they can count as evidence that something unusual is going on. In sum, we need to be guided by science and not just sympathy in risk evaluation. After all, we’re talking about glass; indestructibility and perfect safety can’t be the standards for measuring risk.

As with every product: read the warning label.

What the Media Misses About Antidepressants

A recent meta-analysis in Britain was reported as showing that certain anti-depressants, namely SSRIs, are no better than a placebo in treating depression. STATS Maia Szalavitz explains on Scientific American why the coverage of this study misses the salient point: “when you are looking at aggregated data, huge individual differences can be washed out.”

Some people are strong responders to one drug –but give them another in the same class, and they become actively suicidal. Most people have a slight positive effect; some have a slight negative effect. In aggregate, a drug that is a home run for one person and potentially fatal to another looks inert.

More at Scientific American’s 60- Second Science.

Pyrex-o-mania Continues on CBS Chicago

After scanning the Internet and finding 300 claims of Pyrex dishes “exploding” over the last five years – none of which appear to have been verified as actually involving Pyrex (that would require testing the glass), and without any reliable evidence that the dishes weren’t subjected to the kind of use the warning labels warn against, CBS 2 Chicago’s award-winning investigative reporter Pam Zekman turned to experts to find out what was going on in the second-part of an expose on how glass can… um… break.

The maker of Pyrex, World Kitchen, supplies test results to the station showing how the dishes can break if subjected to extreme temperature changes, but these aren’t dramatic enough, so CBS turns to Professor Sheldon Mostovoy, PhD, of the Illinois Institute of Technology to devise more tests to get the dishes to break. Finally, one dish, heated to 450 degrees, filled with sand to simulate food, and placed on a wet granite counter cracks, sending a shard of glass six to eight feet away. Which is what one would expect, given the laws of physics and the nature of glass.

A smoking gun? No. After all this, Zekman tells viewers that Mostovoy believes Pyrex is safe. It’s the safety instructions that are inadequate. Well, you can be the judge, as here’s the opening paragraph from the leaflet that accompanies Pyrex bakeware:

READ and SAVE
WARNINGS

Failure to follow these instructions can cause breakage resulting
in injury or property damage.
• NEVER USE ON TOP OF STOVE, under a broiler, in a toaster
oven, or place over oven vent or pilot light.1
• AVOID SEVERE HOT TO COLD TEMPERATURE CHANGES and
DO NOT add liquid to hot dish, place hot dish or glass cover in
sink, immerse in water or place on cold or wet surfaces.2
Handle ALL hot ovenware and glass covers with dry
potholders, including ware with Silicone gripping surfaces.
• DO NOT use in microwave to hold or support popcorn bags,
microwave convenience foods with special browning
wrappers, etc.
• DO NOT use to pop corn, caramelize sugar, or deep fat fry.
• DO NOT overheat oil or butter in microwave. Use minimum
amount of cooking time.
• DO NOT use or repair any item that is chipped, cracked, or
scratched… [etc]

Professor Mostovoy thinks the lettering is too small. Another professor, Jack Mecholsky, Ph.D, of the University of Florida believes the warnings are too difficult to follow – even though hundreds of millions of Pyrex and other glass dishes are being used daily without catastrophic results. (One is tempted to say that if you can’t understand the warnings above, how can you possibly follow a recipe?).

Finally, the Consumer Product Safety Commission tells CBS Chicago that it doesn’t believe Pyrex is a “safety hazard.” But that’s still not good enough for Zekman: there will be a third segment running tonight (that’s Pyrex three nights running) to figure out what is going on.

Here’s what’s really going on: CBS Chicago is desperately trying to salvage some point to an investigation, which presumably ate up a lot of money but managed to turn up nothing more substantial than an opinion that the warning label should have larger lettering. This should be laughable; but even though CBS failed to verify any of the anecdotes about exploding Pyrex (see yesterday’s post), and essentially relies on self-reported incidents from other Internet sites (since when is this a credible method of reporting?), the fact that it keeps associating a product with a risk functions like bad advertising. When people hear the word Pyrex, they’ll think, “oh, doesn’t that explode?

And once that starts happening, how long can it be before people begin filing lawsuits claiming that they have been emotionally traumatized by the sound of exploding dishes?

CBS Sweeps Week Shocker: Glass Can Break!

Chicago’s CBS affiliate has discovered the laws of physics, and the shocking news is that…um… glass can break. Like, if you drop a dish made of glass it can… break (mechanical breakage), or if you put a very hot glass dish in cold water it can… break (thermal downshock).

In a segment blowing gale-force spin, CBS 2 tries to make out that a supposed spate of ‘exploding’ Pyrex dishes means that…um, glass bakeware isn’t safe. And if something isn’t perfectly safe, well, the question of where to apportion blame can’t be far behind.

“It may be the most popular glass bakeware in America,” said co-anchor Rob Johnson. “But tonight, some cooks are asking, ‘Is there a problem with Pyrex?” CBS investigative reporter Pam Zekman turned to one family for a shocking anecdote:

JULIA TUSO (Pyrex User’s Daughter): When it hitted (sic)
me in the hand I–I was crying. That’s why I said, ‘Mommy, I’m scared.’

ZEKMAN: Her mother had just taken a year-old Pyrex dish
out of a 350-degree oven. She put it on the oven door…

Ms. GINA TUSO (Pyrex User): .and when I turned back to
get a fork to flip the steak, I heard a loud explosion.

Mr. JOE TUSO (Pyrex User): There was glass scattered
everywhere, from 10 to 15 feet away from where it happened;
in three separate rooms.

ZEKMAN: Their daughter Julia was sitting across the room
at the kitchen table and was burned on her hand and neck by
a piece of flying glass.

First, glass doesn’t actually explode; it just sounds good for TV to say it does. It may sound like an explosion when it shatters (the sound is of atomic bonds being ripped apart), but there is no expulsion of gas, which is the signal for a true explosion. Glass can only be broken in tension, either by dropping it on a hard surface, hitting it with something, or subjecting it to dramatic changes in heat, which puts different areas of the glass in tension. So, for example, when a hot dish is placed on a cold surface or in cold water, the cooled surface shrinks in comparison to the glass inside, and the tension makes the glass break. Abrasions from, say, a chip or scoring a glass dish with a knife will exacerbate breakage.

So what actually happened in the Tuso’s kitchen? The only thing we know for sure is that the laws of physics weren’t broken along with the dish. It had to have been dropped, or have some prior damage, or have been exposed to extreme temperature change or some measure of all three. These are the only ways glass can break. But there are some real problems with the story – beginning with cooking a steak in an oven at 350 degrees and needing to flip it. Who bakes steak? Were the Tusos actually broiling the steak? If so, this is something Pyrex warns you not to do with glass bakeware.

It’s also hard, given that the dish apparently shattered on the door of the oven, to understand how the force projected upwards across the room to where their child was sitting, injuring her neck. The position of impact and the food in the dish would have directed the force outwards and downwards. Odd too is the fact the the shard of glass, apparently, retained enough heat after traveling a considerable distance and possessed enough sticking power to cause a burn.

[update - after reviewing the video, the wall oven appears high enough not to require upward force.]

But the questionable aspects of this kitchen misfortune raised no questions; instead, to make something more significant out of this misfortune, CBS 2 trawled a bunch of consumer websites for corroborating events in order to create the idea of an explosive trend – and it found some 300 incidents over the past five years.

But wait: Did CBS 2 verify that each of these events involved Pyrex? Did it check out the conditions in which the breakage occurred? Or did the reporters simply assume that an anecdote on a consumer website must be about Pyrex and must be a case of explosive shattering? No systematic analysis is presented by Zekman, so one can only conclude that they skipped checking the details out.

CBS 2 also cited the Consumer Product Safety Commission’s (CPSC) list of 66 complaints about for the last 10 years. That’s 6.6 complaints per year for 369 million Pyrex glass products manufactured since 1998 – assuming that the complaints did actually refer to Pyrex and not a rival glass product (once again, no-one checked). Add that number to Pyrex dishes still being used from before 1998, the overall rate of usage (say times per week), and one is left wondering: by what rational measure is this a problem worthy of headline treatment?

Based on emergency room data for 2005, you had a 1 in 3,706, 338 chance in the United States of sustaining a non-fatal injury from glass bakeware that didn’t shatter from mechanical breakage (i.e., being dropped). And even that is a crude estimation – a more accurate picture of the risk would involve the chance calculated per times glassware was used in cooking during the year, or per hour of cooking usage. For 2006 all calculation is moot: there were no injuries recorded by emergency rooms participating in the CPSC database, so the risk, as best we know, was zero. All of which means, compared to other kitchen equipment, glass bakeware is pretty darn safe. Take blenders for example, based on 2006 data, you have 1 in 95,152 risk for a non-fatal injury. And they have moving blades.

Because CBS 2 can’t figure out a way of explaining how Pyrex glass could defy physics and break in some special way that presents a hitherto unknown risk, the segment resorts to trying to show that the safety instructions are confusing to people whose Pyrex bakeware shattered (well, they think it was Pyrex, again no-one has checked). But the instructions explicitly warn about temperature changes and other conditions that can cause breakage and the overwhelming majority of people seem to be able to use their glass bakeware without mishap. CBS 2 promised a second segment tonight showing the results of its safety tests.

But if glass bakeware is going to be a benchmark for risk, and a handful of anecdotes the measure of a problem, people should stay out of the kitchen altogether. That’s where knives cut, and water boils, and things get hot. And, in fact, to be super-duper safe, people should probably avoid watching local TV news too, and not because it can damage your sanity, but because vastly more people injure themselves from television sets in the U.S. each year than from glass bakeware or blenders – in fact, based on 2006 data, you had a 1 in 5,613 chance of incurring a non-fatal injury from lifting, moving, and, believe it or not, watching TV.

Will Smoking Pot Really Make Your Gums Rot?

Rebecca Goldin, Ph.D and Jenna Krall

A recent study of pot smokers revealed that they have significantly increased cases of periodontitis. But are marijuana users really known for their good brushing habits?

As reported by the Washington Post, heavy pot smokers are 60% more likely to develop early gum disease. The study claimed to “account for tobacco use, gender and a lack of dental care.” However, in this study, dental care refers to regular visits to the dentist, not daily brushing. Dental plaque was measured (and controlled for), but brushing habits were not considered. In other words, the Post didn’t take into account that pot smokers might not brush their teeth as often as the American Dental Association recommends (or as much as those who don’t smoke).

The Post also reports that “heavy marijuana users have as much as three times the risk of developing serious gum disease compared to those who haven’t smoked pot.” The implication is that smoking pot causes gum disease (as smoking tobacco is well-known to do). Putting aside the illegality issue, the article implores people to stop smoking marijuana for their own health.

In terms of finding a “causal pathway,” it may well be that smoking pot lowers people’s willingness or interest to take care of their teeth by brushing and flossing (and hence quitting pot would improve your gum health). It’s also possible that those less interested in their teeth are more interested in pot.

In sum, though this article suggests that smoking pot causes gum decay, it is entirely possible that heavy marijuana users are simply unconcerned for the well-being of their gums.

If You Vomit While Talking to a CBS Reporter Are You Allergic to CBS?

We’ve been following the claims that new fire safety standards on mattresses are exposing people to chemicals for a while now, largely because they’ve been driven by some wild and crazy statistics (300 million will be harmed or killed, according to People for Clean Beds, an activist group started by a green mattress maker). But somehow we missed this exceptional piece of consumer reporting “New Fire Retardant Mattresses Source of Toxins,” which appeared on the New York CBS affiliate on December 21.

It’s worth watching, simply as a guide to how not to create a scientifically credible consumer report.

Step 1. Find a victim, believe what they say… immediately
Who knows where CBS found Joan Kramer, or what in fact is wrong with her and her husband. She claims that both of them experienced difficulty breathing, swollen eyes, and splitting headaches after sleeping on a new mattress. They blame the chemicals – and that’s good enough for CBS to build a segment on.

Step 2. Don’t call a doctor, don’t test the mattress
Undoubtedly Mr and Mrs. Kramer had a few rotten nights sleep; but what actually caused their symptoms? If self-diagnosis was a reliable method of figuring out what made us sick, we wouldn’t need doctors. Second, Mr and Mrs Kramer simply intuited causation from the correlate of a new bed; did they check for anything else unusual in their environment? How do they really know it was the chemicals in the bed when they never measured anything in their environment?

Step 3. Stick with a sample of one
If the new mattress code is really creating severe allergic reactions, couldn’t CBS find a bigger sample than just one couple and one mattress? That isn’t a statistic, it’s an anecdote. Yes, the segment goes to a factory, where a worker, heavily disguised, claims that making the new mattresses left workers sick. First, this is not a comparable situation: occupational exposure is fundamentally different to bedroom exposure. Second, the numbers of workers complaining of a reaction were small, and the the Occupational and Safety Health Administration (OSHA) conducted a detailed inspection of the plant and found nothing hazardous.

Step 4. Distort the science
The Consumer Product Safety Commission conducted extensive migration/exposure assessment studies that looked at the potential for dermal absorption, inhalation and ingestion of fire retardant chemicals in adults and children (including cases of bed-wetting), and aging of the bed, and concluded in its document, “Quantitative Assessment of Potential Health Effects From the Use of Fire Retardant (FR) Chemicals in Mattresses,” that exposure to the chemicals required by the new standard did not come anywhere close to levels where there might be negative health effects. But while CBS showed this actual document to viewers on camera, it distorts its contents. “The research finds they [the chemicals] are human carcinogens and toxins,” says the reporter. But the report says they aren’t a risk because “the toxins are trapped inside the mattress.”

Step 5. Talk to an expert who has no expertise
Interview an environmental activist, in this case Emily Main of the Green Guide. She claims that it’s hard to measure how much chemicals the mattresses expose people to, so the CPSC has gone with an “innocent until proven guilty approach.” But that’s flat out false, which Main and CBS would have understood if they’d read the risk assessment. The CPSC’s goal is to protect consumers; it isn’t a profit-hungry corporation; and it went so far in its tests as simulating peeing on the mattress to see if urine would trigger chemical release.

Step 6. Don’t talk to a real expert, even for the sake of journalistic balance
Don’t, under any circumstances, interview a toxicologist, a representative of the CPSC, an allergenist, or anyone with a scientific credential. That just complicates things. CBS went, instead, to ABC Carpets and Homes in New York, where they found “natural” fire resistant bedding that doesn’t need fire retardant chemicals. The saleswoman told CBS that their mattresses are exposed to a flame for 90 seconds and if they don’t catch fire, then they’re fire resistant. But that’s not what the CPSC’s new  standard is about. It has to do with delaying a fire from reaching flashover, the point where so much heat is released that everything in the room spontaneously catches fire. The question for ABC Carpets and Homes is how long after catching fire their beds reach flashover, but clearly it didn’t occur to the CBS consumer report team that there was a difference.

Result: One advertorial
What CBS produced is an advertorial for ABC Carpets and Homes, more suited to a shopping channel. By failing to test any of the claims for a risk against the science, by using a sample of one self-diagnosed couple, by testing nothing, and not even bothering to interview someone from the CPSC, let alone an independent toxicologist, the viewer is left with the message: buy a bed at ABC if you want to be safe.

And this junk just keeps on coming. WTHR Indianapolis have just promo’d “Sleeping with Danger” which breatlessly announces that:

13 Investigates has learned many new mattresses contain toxic ingredients, and those ingredients are making people sick. Investigative reporter Bob Segall shows you what’s really inside mattress, and what mattress manufacturers are not telling you.

To inoculate yourself now, read STATS “Attack of the Killer Mattresses – Coming to TV News Near You!” We’ll be sure to point out every mistake made by the report once it airs.

How To Save Someone Who Overdoses

STATS’ addiction and recovery expert Maia Szalavitz has some practical, no-nonsense advice on the Huffington Post about how to deal with drug overdoses.

If someone is just out of rehab, be aware that they can’t handle the same high doses they were once taking – and that they may not realize their bodies have a much lower tolerance for drugs.

Don’t let someone “sleep it off” if they lose consciousness; if they are unresponsive and start turning blue, call 911 immediately.

But most importantly, if someone you know or live with is taking opioids -

“obtain some naloxone (brand name: Narcan). This is the antidote to opioid overdose and it can save lives even if the opioid is just one of many drugs in the mix (it will not work if opioids are not involved, however).

The Chicago Recovery Alliance has handed out over 10,000 doses of naloxone since it began its overdose prevention and reversal campaign– and some 800 people have reported back to them that they used it in an overdose situation, according to founder Dan Bigg.

Of these 800 cases, remarkably, there were only one or two deaths and no cases where the person seemed permanently harmed– and in one of the deaths, the person was apparently already dead before the naloxone was tried. This is an extraordinary recovery rate: one study found that 10% of overdoses managed at home without naloxone ended in death.

For more practical information on what to do in overdose situations, check out the rest of Szalavitz’s article.

European Scientists Poo-Poo Baby Bottle Risk

Environmentalists are going bonkers over bisphenol-a (BPA) a chemical component of polycarbonate plastic bottles. A new report by a coalition of environmental groups, The Work Group for Safe Markets, calls for a moratorium on the use of the chemical.

STATS gets a lot of stick for challenging these kinds of reports, along the lines of “we must be taking money from the plastics industry or, as a recent post on treehugger claims, beholden to some ultra-conservative, pro-industry ideology.

We’re not – on either count. And we aren’t making up the science; we’re just pointing out what the science actually says – or rather, that there’s a whole lot of science ignored by the environmental activists, and that their claims about impending doom never address, on a methodological level, why this rival science is inferior).

In the case of BPA that would include a massive risk assessment by Europe’s Food Safety Authority, which was conducted by independent scientists. Basically, they junked all the science marshaled by the environmental groups as being either badly done (statistically underpowered or didn’t follow accepted international protocols) or not relevant to determining reproductive risks in humans.

Take the common claim, repeated by treehugger, that BPA is a gender-bending chemical. BPA is weakly estrogenic. So, in theory, it could have an effect on the endocrine system. But what happens when BPA is ingested by humans? It’s worked on by enzymes, gains a sugar molecule, loses all estrogenic power and is rapidly excreted in urine.

But this is not what happens when BPA is administered to rats and mice either orally or intravenously. In each case the metabolic pathways are different and there is more free BPA and/or other metabolites swimming around. This is, at a highly simplified level, why independent European, Japanese and American risk assessments rejected the studies cited by environmentalists. (For more, see Should You Be Worried About Toxic Baby Bottles?)

The European Union sets a specific migration limit (SML) rate of 600 parts per billion per day for children when it comes to BPA migrating from plastic contact to food. As the European Food Safety Agency recently raised the Tolerable Daily Intake (TDI) of BPA by a factor of five, this SML is now effectively 3000 parts per billion. The plastic bottles in the The Work Group for Safe Markets required 24 hours at 176 degrees Fahrenheit to produce a migration level of 5 to 7 parts per billion.

Leaving aside whether this method of extraction models a likely exposure route in the real world, there is the question of whether, even if such tiny amounts of BPA are ingested, they could have any damaging effect once processed in the intestines and liver. The very latest research – and one of the most rigorous studies to date – does not suggest so, even for infants. It examined whether gestational and lactational exposure to BPA and the oral contraceptive Ethinyl Estradiol (EE) would damage male reproductive systems and alter hormone levels at very low doses in rats. EE did; BPA didn’t. In fact, the researchers found no significant effects for BPA at all. And bear in mind that rats are more susceptible to BPA than humans.

If environmentalists want to be credible in their demands for moratoriums, bans and so forth, they must account for why their science is superior to the research that challenges their hypotheses. Anything else is propaganda.

Why We Shouldn’t Rush to Blame Heath Ledger’s Death on Doctors

Over on the Huffington Post, STATS’ Maia Szalavitz takes on some of the responses to the medical examiner’s report on actor Heath Ledger’s death, particularly the suggestion that one or more doctors may be “responsible” for his death rather than it being a consequence of drug abuse.

The problem, she argues, is that there is often a stigma to acknowledging that someone is addicted to drugs. But

The fact is, the vast majority of people who die from combinations of opioids and benzodiazepines — especially with several drugs from the same medical class in their bodies, especially if opioid painkillers are involved — are not taking their drugs as prescribed. They are addicts or, at least, drug misusers.

It’s conceivable that Ledger had a corrupt or profoundly incompetent doctor, but the more parsimonious explanation, given his history of recreational drug use, is that he was not following doctor’s orders at all.

This is important because blaming doctors for these deaths hurts pain patients and people with anxiety disorders who legitimately need these medications. Every time people avoid the hard truth about particular overdoses, legitimate patients get punished by restricted access to necessary medications and even denial of medication for excruciating pain or anxiety.

Also check out Maia’s earlier post “How not to die like Heath Ledger, Part II“