Understanding Hazards vs. Risks: Why Not All Chemicals Are Dangerous
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Chapter 1: The Misunderstanding of Dihydrogen Monoxide
Recently, I found myself in a conversation with my easily influenced friend, Gulliver. As expected, he was agitated about something he had seen online.
“Have you heard about that study?” he queried. “The one on dihydrogen monoxide?”
“What’s that?” I asked, intrigued.
“It’s a chemical! An odorless, tasteless, colorless chemical! And it’s incredibly dangerous!”
“Dangerous? In what way?”
“It’s responsible for all sorts of alarming things! It’s a powerful greenhouse gas, can cause explosions when mixed with sodium, erodes metals, leads to electrical malfunctions, contributes to soil erosion, and prolonged exposure can damage tissues. It can even be deadly!”
“Deadly?!”
“Absolutely! If you consume too much, or worse, inhale it, it can kill you!”
“Wow… Does the government know about this?”
“Of course they do! But they’re indifferent. They won’t take action even though it’s everywhere!”
“Everywhere?”
“Yes! It’s used in chemical processes, coolant systems, and even in nuclear weapon production. It’s present in exhaust, a component of acid rain, and they even spray it on crops and put it in our food! The whole world is contaminated! You’re probably inhaling it right now!”
“Good grief…”
“I know! I have to hop on Facebook to alert everyone! You should spread the word on Twitter too.”
“Hold on a second. I’d like to understand what exactly this chemical is first.”
“It’s a dangerous chemical! It’s in our food! It’s a hazard! What more do you need to know?!”
“Did you just say it’s a hazard?”
“Yes! Scientists say it’s a hazard.”
“And what does that mean exactly?”
“Are you serious? How can you not know what a hazard is?”
“I have a general idea, but I’m not sure of the precise scientific definition.”
He stared at me, puzzled.
“Let me look it up…” I replied.
“Yeah, go ahead. But I don’t have time for this. I need to warn my friends and family!”
And with that, he was gone.
Risk vs. Hazard
In case you missed the joke, dihydrogen monoxide is simply H2O—water. Using its scientific name can make it sound terrifying. This classic prank highlights how fear of chemicals and a lack of scientific understanding can lead to unnecessary alarm. The confusion between hazard and risk often sparks these fears, and it’s essential to clarify these terms.
According to the World Health Organization, a hazard is “any biological, chemical, physical, or radiological agent that has the potential to cause harm.” In contrast, risk refers to “the probability of identified hazards causing harm in exposed populations over a specified timeframe, including the severity of that harm and/or the consequences.” To put it simply, a hazard indicates the potential for harm, while risk assesses the likelihood of that harm occurring.
Interestingly, pure water can be classified as a hazard. It has the potential to harm: excessive consumption can lead to water intoxication, and inhalation can result in drowning.
When people panic about a pesticide or preservative, it often stems from confusing these two terms. A hazard identification study identifies substances that could potentially cause harm, while a risk assessment study evaluates the likelihood of that harm under specific conditions.
For example, when the International Agency for Research on Cancer (IARC) classified processed meats as carcinogenic, they were conducting a hazard identification study. They suggested a strong probability that processed meats can cause cancer, similar to recognized hazards like smoking or asbestos. However, this does not inform us about the actual risk of consuming processed meats or being exposed to water.
To assess how dangerous something truly is, we need a risk assessment study. Such studies evaluate the likelihood of a hazard causing harm based on factors like dosage or exposure duration. For instance, they might determine the probability of developing bowel cancer after consuming a pound of smoked bacon daily for two decades.
Consider white sharks as another example. They are inherently dangerous, making them a hazard, but if you live far from the ocean, you’re not at risk. Even if you’re in shark-infested waters, standing on the beach with minimal exposure means you’re not at risk of harm.
Therefore, the next time someone claims that “they” are trying to harm us because a scientific study has identified a substance as a hazard, take a moment to investigate. Understand what the study actually conveys.
Chapter 2: The Need for Perspective
You need not fret about tiny pesticide residues on your apple, preservatives in your food, or even a glass of water on your counter. While these substances may be labeled as hazards, the actual risk of harm is often negligible.
It's crucial to remember that just because something poses a potential danger (is a hazard) does not mean it is likely to cause harm (is risky). The risk associated with a hazard depends on various factors, including duration and frequency of exposure. Simply knowing that something is a hazard doesn’t provide enough information to determine whether it’s a legitimate concern.
In reality, there are pressing risks in our society that require attention—climate change and plastic pollution being two of the most significant. If we treat every chemical or hazard as equally dangerous, we will struggle to address these genuine threats.
So, enjoy your fruits and vegetables, and take your vaccinations. They won’t harm you but will help mitigate the real risk of illness. And don’t hesitate to drink your water; you’re safe.
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