Most product labels are uncontroversial. They provide information that people want to know, or that somebody wants them to know. Labels on potentially harmful products are uncontroversial, too. Foods containing peanuts, for example, need a label so consumers with peanut allergies can avoid them. Ditto for workplace risks. A drum that contains a carcinogenic chemical needs a warning sign.  But should we label a product in the supermarket or a chemical in the workplace that contains a substance many people consider dangerous but most experts consider safe?  Take, for example, a food with a genetically modified ingredient. According to a 2015 Pew Research Center report, 88 percent of scientists think GM foods are safe, compared with only 36 percent of the general public. Should GM foods carry a label so consumers who want to avoid them can do so?  It’s arguably rational to steer clear of a food ingredient that confers no known consumer benefit and that 12 percent of scientists consider dangerous. But let’s ignore that for the moment and assume that it’s foolish to worry about GM foods. Does that mean it’s foolish to label them? The case for labeling a presumptively safe product that some people mistakenly consider dangerous is straightforward: transparency, or the “right to know.” Give people true information they want, thereby enabling them to act on their own judgments and preferences. To many people this is a self-evident ethical precept: if people want to avoid a particular risk, how dare companies deny them the relevant information merely because the companies think they’re being silly? 
The case against labeling is more complicated, but not foolish. A GM label, especially a mandatory label, is said to imply that there must be something wrong with GM foods. Assuming this implication is false, the label misleads the public, distorts the market, unfairly stigmatizes GM foods, and discourages the technological improvements that genetic modification could yield. Based on this reasoning, many scientific organizations oppose mandatory labeling. In 2012, for example, the American Association for the Advancement of Science stated that mandatory GM labels “can only serve to mislead and falsely alarm consumers.” What are the risk communication implications of GM labels? Do they falsely alarm consumers as the AAAS concluded, or might they actually have a reassuring effect? And  can this discussion be extrapolated to the broader issue of informed consent when you think people are wrongly fearful? What should you do (and what should you be required to do) with accurate information that you think may unduly alarm your audience?  RISK COMMUNICATION PRINCIPLES A core principle of risk communication is that outrage largely determines hazard perception. When people think something is riskier than the experts think it is, odds are their outrage is a major cause of their overreaction. So, a core risk communication task is to figure out how to reduce their outrage. According to risk communication principles, labeling reduces outrage. Of the 12 outrage components on my A-list, labeling moves at least four in the low-outrage direction: control, voluntariness, familiarity, and trust.  A label that tells you a product contains GM ingredients makes you feel more in control; it makes your decision to accept the risk more voluntary; it makes you more familiar with the risk and thus more used to it and increasingly desensitized to it; and it makes you feel more trust in whoever has so candidly alerted you to the situation. Another factor that makes labeling an outrage reducer is cognitive dissonance. Even consumers who try to avoid products with a GM label usually end up buying such products from time to time. Each decision to knowingly choose a GM food is a risk communication message to themselves that they’re not all that worried about genetic modification. It’s hard to keep buying and eating GM foods and remain fervent about how dangerous GM foods are. But labeling can work the other way, too. The decision to alert people to the presence of GM ingredients does imply that the GM ingredients are something they might want to consider avoiding. A GM label inevitably makes more salient in consumers’ minds whatever they have heard previously about the controversy over GM foods.  So labels have two effects that work in opposite directions: the outrage reduction effect and the hazard salience effect. The question is, which is greater? I have long thought—for genetically modified foods in particular and for informational labeling in general—that the outrage reduction effect is usually the greater of the two.  The outrage reduction effect of labeling, in fact, is a significant problem for labels meant to warn. Like a neutral informational label, a warning label also increases control, voluntariness, familiarity, and trust. And those who take note of the warning but proceed nonetheless are bound to experience some cognitive dissonance that that they will reduce by telling themselves the risk doesn’t worry them. Thus, it is hard to design a warning label that keeps warning people; the outrage reduction factors built into repeated warnings tend to vitiate the intended arousal of concern.  Of course, if you’re undyingly committed to avoiding a particular product ingredient—you’re allergic to peanuts or you hate garlic or you’re terrified of GM foods—your reaction to that information on labels probably won’t wane much. People who unfailingly search out certain information and unfailingly act on it are more or less immune to “warning fatigue” (as it’s called). But most of the time, most people habituate to labels, even warning labels.  Here’s my analysis of the likely effects of GM labels:
  • Consumers who are fervently anti-GM will use the labels to help them avoid GM foods. The labels’ candor will increase their sense of trust; the labels’ usefulness will  increase their sense of control and voluntariness. So, I’d expect their anti-GM fervor to diminish a little over time.
  • Consumers who are pro-GM will use the labels to help them seek out GM foods. There’s certainly no labeling downside for that group.
  • The majority of consumers are undecided or uninterested. They may not notice the labels. If they notice them, in the short term, some would be reminded that they’ve heard that GM foods are dangerous, and/or would experience the labels themselves as signaling a possible danger, so they would avoid the labeled products. That’s the hazard salience effect opponents of labeling are worried about. But consumers would encounter lots of products with GM labels, and they’d see lots of people buying those products with no detectable negative outcomes. Sooner or later they’d buy these products themselves, again with no detectable negative outcomes. Over time, familiarity, desensitization, and cognitive dissonance would make these consumers less and less attentive to the labels and less and less worried about GM foods. 
If that’s the effect of GM labels, what is the effect of the decision not to label? Presumably, it has no short-term effect; it’s a nonevent. But the GM controversy doesn’t go away just because GM products aren’t labeled. Insofar as people are paying attention to the controversy, their concern can easily be exacerbated by the absence of labels and the resulting near-impossibility of protecting themselves. Worse yet, people who haven’t paid attention to the controversy until recently tend to experience post hoc outrage at having been hoodwinked into buying products they would have avoided (or now think they would have avoided) if only those products had been properly labeled. In short, people who are worried about a situation or substance they consider dangerous may actually become more worried when the relevant information is (or was) kept secret and less worried when it has been shared candidly.  That’s what risk communication theory predicts. What’s the evidence about the effects of GM labels? GM LABELING RESEARCH EVIDENCE Reviews of the literature on the effects of GM labeling tend to conclude that the evidence is “mixed.” If you ask people how they would respond to GM labels, you end up concluding that the labels will probably deter a lot of purchases of GM-containing products. But if you look at how GM labels have actually affected sales, you end up concluding that (in the U.S., at least) there is little, if any, impact.  I am less interested in how labeling affects short-term sales than in how it affects long-term attitudes. Risk communication theory suggests that the hazard salience effect should mostly be short term, diminishing as people get used to the labels, whereas the outrage reduction effect should increase over time as control, voluntariness, familiarity, trust, and cognitive dissonance work their wonders. So, I’d expect GM labels to be a bit scary at first, but calming in the long run. In 2016 Vermont became the only state to require GM labels on foods. Vermont’s law was preempted less than a year later when Congress passed a national GM labeling law (which hasn’t yet been implemented). This provided an ideal opportunity to investigate the real-world effects of GM labels. For a while, many foods in Vermont had GM labels, whereas the vast majority of foods elsewhere in the country did not. How did the attitudes of Vermonters toward genetically modified food ingredients change during this period, compared with the attitudes of non-Vermont U.S. residents?  A study published in June 2018 provides the answer: “Mandatory labels can improve attitudes toward genetically engineered food.” Before mandatory labels appeared in Vermont, consumer attitudes were somewhat more negative toward GM foods in Vermont than elsewhere in the country. But after Vermonters had had six months to get used to the labels, their opposition to GM foods had declined substantially, while GM concern climbed modestly in the rest of the country. By the end of those six months, Vermonters’ opposition to GM foods was 19 percent lower than it would have been if the pre-labeling gap between Vermonters’ attitudes and nationwide attitudes had remained constant.  The Vermont study is the best evidence so far that the outrage reduction effect of GM labels tends to be greater than the hazard salience effect.  THE CASE FOR INFORMED CONSENT Labeling is a kind of informed consent. And informed consent is usually an outrage reducer. People who are exposed to a risk without forewarning rightly become outraged when they learn they have been deceived—and their outrage leads them to see that risk as vastly more harmful than it is. People who are told about the risk and given the choice, on the other hand, have far less reason to be outraged, and far less reason to overestimate the hazard. That’s true whether they accept the risk or decide to avoid the exposure.  The outrage reduction effect of informed consent is usually greater than its hazard salience effect. (Even when risk exposure is mandatory and there’s no opportunity to “consent” or not consent, candor about risks still tends to reduce outrage. But that’s a different topic for another day.)  But what about the times when the opposite is true—when a label or some other mechanism of informed consent arouses or exacerbates unjustified concern (hazard salience) instead of ameliorating that concern (outrage reduction)? Do I still advocate informed consent, even in situations where the information makes people likelier to say “no” to something the experts think they should say “yes” to? I do.  Some years ago, for example, I consulted for an organization that was part of the coalition working to eradicate polio. At that time, polio vaccination in the developing world relied on the oral vaccine, which has one significant disadvantage compared with the injected vaccine: on rare occasions it can give a vaccinee polio or even lead to a community outbreak. Polio eradication campaigns had long hesitated to tell parents about this downside of the vaccine, lest it deter them from letting their children be vaccinated. On this, informed consent messaging vis-a-vis polio vaccination was systematically and intentionally uninformative. My advice to come out of the closet about the tiny but real possibility of getting polio from the oral polio vaccine was not taken.  In a website column that analyzed the polio vaccination dilemma in more detail, I concluded: 
Going public with a long-suppressed secret is, of course, more difficult and more damaging than not suppressing the secret in the first place. That’s the core vaccine risk communication problem the Global Polio Eradication Initiative faces today. … It can’t tell the truth about [the vaccine] without also telling the truth about its long history of intentional, deceitful misoversimplification. “Simplifying out” information that conflicts with your message is addictive. Once you don’t admit something you should have admitted, it gets harder and harder to admit it later. When it finally emerges, people don’t just learn it. They learn it in a way that makes it loom much bigger than it would have seemed if you’d been mentioning it all along. And they learn that you have been habitually dishonest. 
That’s the case for informed consent. Over the long haul, public trust requires honesty, even when the short-term result of honesty may be unwise decisions that do real harm.  Tell the truth, even when it hurts. That’s the only way to build and sustain trust—trust in you, in your organization, and in your profession; trust on the specific issue you’re addressing now and on all the issues you will need to address in years to come. Here’s my argument in one summary paragraph: Surprisingly often when we’re tempted to withhold risk information because we think people will overreact in harmful ways, we’re simply wrong; the outrage reduction impact of our honesty overcomes the hazard salience effect we were worried about. Even when the hazard salience effect is the stronger of the two at the outset, people get used to hazard information. Thanks to control, voluntariness, familiarity, trust, and cognitive dissonance, the outrage reduction effect soon overtakes the hazard salience effect. And even if it doesn’t—even if undue concern leads people to unwise decisions—the preeminent importance of long-term trust-building means that honesty is still the best policy. All this is as true for industrial hygienists talking to their work force or their neighbors as it is for food manufacturers deciding whether to label products with genetically modified ingredients.   PETER M. SANDMAN is a risk communication consultant and speaker. Much of his work on risk communication can be found on his website, Comments on this and future columns can be sent to the author and The Synergist.
American Association for the Advancement of Science: “Statement by the AAAS Board of Directors on Labeling of Genetically Modified Foods” (October 2012). Pew Research Center: “Views of GMOs” (January 2015).  Sandman, Peter: “Misoversimplification: The Communicative Accuracy Standard Distinguishes Simplifying from Misleading” (June 2012). Science Advances: “Mandatory Labels Can Improve Attitudes toward Genetically Engineered Food” (June 2018).
What should you do with accurate information that you think may unduly alarm your audience?
Risk Communication Lessons from the Genetically Modified Foods Controversy

Although the print version of The Synergist indicated The IAQ Investigator's Guide, 3rd edition, was already published, it isn't quite ready yet. We will be sure to let readers know when the Guide is available for purchase in the AIHA Marketplace.
My apologies for the error.
- Ed Rutkowski, Synergist editor
Disadvantages of being unacclimatized:
  • Readily show signs of heat stress when exposed to hot environments.
  • Difficulty replacing all of the water lost in sweat.
  • Failure to replace the water lost will slow or prevent acclimatization.
Benefits of acclimatization:
  • Increased sweating efficiency (earlier onset of sweating, greater sweat production, and reduced electrolyte loss in sweat).
  • Stabilization of the circulation.
  • Work is performed with lower core temperature and heart rate.
  • Increased skin blood flow at a given core temperature.
Acclimatization plan:
  • Gradually increase exposure time in hot environmental conditions over a period of 7 to 14 days.
  • For new workers, the schedule should be no more than 20% of the usual duration of work in the hot environment on day 1 and a no more than 20% increase on each additional day.
  • For workers who have had previous experience with the job, the acclimatization regimen should be no more than 50% of the usual duration of work in the hot environment on day 1, 60% on day 2, 80% on day 3, and 100% on day 4.
  • The time required for non–physically fit individuals to develop acclimatization is about 50% greater than for the physically fit.
Level of acclimatization:
  • Relative to the initial level of physical fitness and the total heat stress experienced by the individual.
Maintaining acclimatization:
  • Can be maintained for a few days of non-heat exposure.
  • Absence from work in the heat for a week or more results in a significant loss in the beneficial adaptations leading to an increase likelihood of acute dehydration, illness, or fatigue.
  • Can be regained in 2 to 3 days upon return to a hot job.
  • Appears to be better maintained by those who are physically fit.
  • Seasonal shifts in temperatures may result in difficulties.
  • Working in hot, humid environments provides adaptive benefits that also apply in hot, desert environments, and vice versa.
  • Air conditioning will not affect acclimatization.
Acclimatization in Workers