Every day, people are exposed to a variety of activities or products that could, under certain circumstances, cause harm. There’s a potential for harm or injury in nearly every activity we engage in – whether it’s when we cross a street, ride in an automobile, or play in a baseball game. This potential for harm can be referred to as “risk.”
The terms “risk” and “hazard” may seem to have very similar meaning to most of us, but to a scientist they are actually very different. With respect to chemistry, the terms have very specific meanings:
Hazardrefers to the inherent properties of a chemical substance that make it capable of causing harm to a person or the environment.
Exposuredescribes both the amount of, and the frequency with which, a chemical substance comes into contact with a person, group of people or the environment.
Riskis the possibility of a harm arising from a particular exposure to a chemical substance, under specific conditions.
Here’s an example most people can relate to: Crossing the street presents thehazardof getting hit by a passing car. Butriskis the likelihood of harm actually occurring. There might be no risk of getting hit by a car while crossing an empty street in the middle of the night, but a high risk in the middle of rush hour. There might be a very low risk of getting hit while crossing with the light in a crosswalk, but a high risk while jaywalking.
So to understand risk, we need to know both what the inherenthazardis (getting hit by a car) and the degree ofexposure(the number of cars on the road). Once we understand risk, we can also reduce or manage it – for example, by requiring better marked crosswalks or managing traffic flow.
So what doesriskmean in relation to the products we use every day, and the chemical ingredients used to make them?
What are hazardous or dangerous chemicals of concern?
First things first. It’s important to understand that everything around us, including the entire human body and everything we eat and drink, isentirely made of up chemicals. And all chemicals have inherent properties and can be described by hazard – even water and oxygen (it’s possible to drink too much water, and oxygen can explode).
Chemical ingredients found in everyday products are sometimes criticized as being harmful to human health. But, even though all chemicals can be described by inherent hazard, even water and oxygen, the mere presence of a chemical ingredient does not automatically mean it will cause harm.
What is a chemical hazard?
The actual chance of harm from exposure to a chemical ingredient depends on a variety of factors – including how much of the chemical ingredient is in a product; how the product is used; and what kind of exposure to the chemical typically occurs from using a product that contains the chemical.
How can we test for chemical exposure in everyday products?
我有一个化学成分的过程n consumer products can be assessed for safety, taking into account risk, hazard and exposure. Scientific experts at many government agencies use computerized evaluation procedures, data and testing to establish safe exposure levels for chemicals in certain regulated products. Companies producing consumer products are also responsible for the safety of the products they sell, and many do their own robust evaluations and safety testing.
机构数据和评论帮助创建一个集成的web of safety information and assessment. For example, theU.S. Food and Drug Administrationregulates the safety of materials in contact with food to the stringent safety standard of “reasonable certainty of no harm under the conditions of use.” For detailed technical information, consult the International Toxicity Estimates for Risk (ITER) database, which can be accessed via the National Library of Medicine’s website. ITER presents summary charts comparing risk assessment information from U.S. and international sources and explains the differences in risk values derived by these different organizations.
Understanding risk and how it’s assessed can seem complicated, but it’s the foundation of our ability to confirm the safety of chemicals as used in consumer products.
Chemical hazard definition
A chemical hazard generally refers to a type of occupational hazard caused by exposure to chemicals in the workplace. The hazard associated with a chemical depends on:
- What the specific chemical is
- What chemical(s) it is mixed with, if any
- The relative proportion of the chemical, if it is in a mixture or solution with other substances and chemicals
A video by theUniversity of Michigan Risk Science Centeruses as an example a bottle of bleach to describe the difference between “risk” and “hazard.”
