The difference between safe and risk-free

Update 9:07 p.m. Feb. 10, 2010: Just a quick update. My colleague Tom Dennis called my attention to a similar critique from the American Council on Science and Health regarding argument that there is no safe exposure to secondhand smoke. While I merely point out the difference between what the Surgeon General reported and what anti-smoking folks are saying, the ACSH took aim at the good doctor himself:

The SG goes even further, with this totally outrageous statement: "the scientific evidence indicates that there is no risk-free level of exposure to secondhand smoke." This leaves us with the clear impression that if we merely walk through a smoke-filled room, we have put our health in irreversible jeopardy.

These statements violate the basic tenet of toxicology: "only the dose makes the poison." What is most alarming here is that the top doctor in the land is communicating a message that anything that is harmful at high dose can be lethal at low dose — when that is simply not true.

A careful read of the Surgeon General’s report will reveal that, as I note below, secondhand smoke is potentially lethal with long exposure. Basically, all it really seems to say is the risks of secondhand smoke is about the same as the risks of actually smoking. So, I don’t think the report exaggerates things as much as ACSH argues.

I’ll admit that the "no risk-free" exposure statement is a bit misleading. There is always some risk in everything. There’s no risk-free exposure, for example, to the pesticide the city uses to spray for mosquitoes — For goodness sake, the city even tells us to stay indoors for 20 to 30 minutes — the risk is just very, very small.


The City Beat‘s been getting an unusual number of phone calls about the smoking ban survey with a lot of questions about how it could be that 75 percent of the adults in Grand Forks think it’s OK to ban smoking in bars. (Add the 57 percent that favors banning it in the bar and the 18 percent that favors banning it around the bar.)

Did pollsters just talk to smokers? No, though I’m told many smokers didn’t want to participate in the survey.

How many people did they survey? They called people randomly and 779 chose to participate.

Who did the survey? UND’s Social Science Research Institute.

Isn’t UND opposed to smoking? Yes, it banned smoking on campus, but the SSRI is a professional group of pollsters. You have to trust that people have more integrity than that otherwise there’s no point in believing anything that anyone says because anyone can be bought off. My caller said anyone can be made to say anything if there’s enough money in it. Perhaps my caller was paid off by the tobacco lobby?

Anyway, we know there is a very large number of people that think banning smoking in bars, even over the objection of bar owners, is OK.

The question that no one’s asked is just how accurate is public perception about the hazards of second hand smoke. That’s what’s driving this discussion. In the survey, 68 percent thought that secondhand smoke is a "serious hazard" and 43 percent think that occasional exposure to it is also a "serious hazard." This is like saying secondhand smoke is equal to asbestos or plutonium or something.

I can see how people might think working in a smoke-filled room might be a serious hazard, given the enormous exposure to the stuff, but I find it difficult to believe that occasional exposure could be such a dangerous thing. Walking through a smoke-filled room would hardly seem to be a serious hazard.

We’re talking about smoke. Everyone’s sat by a campfire or been stuck in a traffic jam on a hot day.

So I asked Haley Thorson, the Public Health Department official who heads up the Grand Forks Tobacco Free Coalition, why she and her boss public health chief Don Shields kept talking about there being "no safe exposure to secondhand smoke."

My impression is that what they really mean is there is "no safe _long-term exposure_ to secondhand smoke."

First a bit of background. I took the liberty of tracking down the origin of the "no safe exposure" line and found a reference to the U.S. Surgeon General’s 2006 report on secondhand smoke.

The report actually says: "The scientific evidence indicates that there is no risk-free level of exposure to secondhand smoke."

"Risk-free" is a lot different than "safe" because safe implies that, while there could be some risk, it is negligible. A car that’s "safe" is safe in most circumstances, but certainly not if it’s caught in a head-on collision between two semis. Meat that’s "safe" is safe most of the time, but sometimes safety breaks down at the meat processing plant or in the restaurant and people get e. coli poisoning.

Haley said that secondhand smoke isn’t "safe" because even brief exposure will produce a response in the body. Blood gets thicker because the platelets are "stickier," which then exerts more pressure on the blood vessel, decreasing blood flow and slowing down the heart. The blood doesn’t get to the body as quickly.

But doesn’t the body recover from that sort of thing pretty quickly?

The more times that happens, she said, the greater the probability that there will be permanent damage. So it might be a slight, almost unnoticeable damage at first, but if it happens enough, then the damage becomes cumulative, she said.

People with heart diseases will have it worse, she said.

In other words, we are talking about long-term exposure. If someone were to sit in a bar, say, twice a week, each time spending three hours there, over a year, that’s 312 hours and over five years 1,560 hours, which is about 65 days. So that’s the true hazard.

I wished the public health people would talk about it in those terms rather than use the "no safe exposure" line, which sounds suspiciously like propaganda. Secondhand smoke is bad enough. It doesn’t need exaggeration.

What does the Surgeon General say about this? His report is ridiculously detailed, so I’m not going to pretend I read the whole thing. I skimmed a lot.

First, we know that secondhand smoke — "sidestream smoke" in the Surgeon General report — can cause tumors. They made a lot of rats breathe a lot of secondhand smoke for long periods of time — five months in one case — or condensed the smoke and put on the rats’ skins.

Second, we know there are carcinogens in secondhand smoke, such as formaldehyde, and that stuff gets into the human body.

Third, secondhand smoke screws with your respiratory system. The immune system is injured, increasing the chances of getting some sort of infection. The cells can get inflamed, causing obstruction to the airway, and this is a progressive condition that’s irreversible.

Fourth, secondhand smoke activates the platelets in blood making it, as Haley said, stickier. What that means is there’s a higher chance you’ll get a thrombus or a blood clot. Big enough clots and there’s a risk of a stroke or heart attack. Weirdly enough, nonsmokers are way more susceptible to this than smokers, maybe because the smokers’ bodies are used to smoke and doesn’t get too excited about it.

Secondhand smoke also reduces the amount of oxygen that blood can carry to the heart and damage heart cells’ ability to use oxygen.

Basically, you’re not going to get a heart attack from sitting in a smoky room, but you could if you did it a lot.

There’s more, but I don’t have time to slog through what’s basically a 700-page medical journal. But, you get the picture.

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7 Responses to The difference between safe and risk-free

  1. carol says:

    Explain to me why my mom lived to 90 yrs with a cig smoking husband.

  2. Bill Nye says:

    Tu-Uyen, I think you hit the nail right on the head with the hammer. It is all about being safe within the framework of taking risks. Undoubtedly there is a risk to public health with exposure to secondhand-smoke, whether that is short or long term. We are all individuals within a population, so for some of us that “safe” level of secondhand-smoke exposure is lower than say for example Carol’s mother in the previous post. The position of the SG, PHD and majority of Grand Forks citizens is that this “risk” of secondhand-smoke exposure for even one person in our community’s workplaces and public venues is too great. We can make our community “safer” and reduce this “risk” for everyone by asking our elected officials to directly enact a comprehensive city smoke-free ordinance.

  3. Ugh says:

    Carol: That’s called the fallacy of individual experience and it’s a terribly ignorant way to judge the world. See also, look at this blizzard, global warming must be a myth! Or, Chinese people don’t exist because I’ve never met one.

  4. wolfGF says:

    We do a lot of things in this country that don’t make sense. Like banning marijuana, while 15,000 traffic deaths due to alcohol consumption continue unabated. And now that the Supreme Court has blocked the ban on corporate spending on political campaigns, corporations will buy off our lawmakers even faster.

  5. Anonamouse says:

    Dr. Michael Siegel (google him), who was one of the main proponents of smoking bans even years ago and is a public health doctor, says that these days the risks/harm from second-hand smoke have been overexaggerated by the groups on a moral crusade. He calls what they do with information about SHS “junk science” and he says it ruins the credibility of scientists who are trying to keep to the facts. What he emphasizes, as did Tu-Uyen, is that long term, excessive exposure, in close quarters, is the culprit, not the couple hours a person might spend in a bar, where the temporal and quantitative exposure is much, much less.
    Those few establishments who allow smoking in GF are such a tiny percent of all the thousands of businesses and public places where smoking is prohibited (including bars which have voluntarily gone smoke-free) that I don’t see this as a public health issue but as an attempt to impose moral sanctions on a portion of the population. I’s not public health anymore, it’s a jihad.
    When the city restricted smoking some years ago it had also allowed bars to remain open 1 hour longer. Now there’s a proposed increase in cigarette tax. Do we speak out of both sides of our mouths? Are we promoting drinking but coming down hard on smokers? Both are legal. Both have the potential to cause harm. One smells worse than the other but other than that I can’t see any more of a public health problem from smoking than drinking. I wonder if ND still ranks in the upper half of states who have 50% or more of road fatalities caused by alcohol?

  6. Anonamouse says:

    Yeah I just checked, and in 2008 in ND, 50% of all traffic fatalities involved alcohol. We are way above most states in this high percentage.

  7. Avatar of Tu-Uyen says:

    I should point out that I didn’t write this post in opposition to any smoking ban. I was just noting some exaggerated claims.