Single-Use Plastic Containers Are Disaster Waiting to Happen
Think that leftover yogurt container is perfectly fine to zap for a quick meal? Single-use plastics like those used for yogurt, cottage cheese and other foods should never be microwaved. Cold storage containers like cottage cheese and yogurt cartons are not approved for use in the microwave. The problem is these containers weren’t designed to handle heat at all – they’re meant for cold storage only. When you microwave them, they can melt, warp, or release harmful chemicals into your food. Single-use containers, like margarine tubs, tend to warp or melt in the microwave.
Even worse, exposing plastics to heat (like microwaving) can increase the risk of transferring these substances to your foods. Micro- and nanoplastics also shed from plastic packaging into food at room temperature but the process of chemical migration and the shedding of microplastics both speed up when plastic is heated.
Styrofoam Takeout Containers Release Toxic Chemicals
While Styrofoam is good at keeping your food hot in the short term, reheating it is hugely risky. Heating these containers may cause the release of styrene, a compound in the foam which has been linked to the development of several types of cancer, according to research published in Epidemiology. This styrene can work its way into your food, and then into your body.
Styrofoam, or expanded polystyrene (EPS), is not safe for microwaves. Microwaving a polystyrene takeout container can release decomposing harmful chemicals into the food. The structural integrity of these containers is also compromised when heated. EPS containers, however, are particularly prone to cracking when heated in the microwave, which can cause food spillage or burns. Styrofoam cups can release toxic fumes when heated and should never be microwaved. Styrofoam cups are one of the worst offenders when it comes to microwave safety. The material breaks down under heat and can release toxic chemicals, including styrene, which has been linked to health risks.
Aluminum Foil Takeout Containers Can Spark Fires
Your Chinese food came in that shiny aluminum container, but don’t even think about popping it in the microwave. Putting aluminum in the microwave can be dangerous. When exposed to the electromagnetic waves, aluminum reflects them and can cause sparks, leading to fires. Aluminum is a metal, and metals in microwaves can cause sparks due to the way they reflect microwaves. These sparks can damage your microwave or, in extreme cases, start a fire.
Foil food containers often have crinkles and wrinkles built in to them, but these irregularities cause sparks to form on their surface, increasing the chance that they’ll set something alight. Even if the container looks safe, foil containers can cause “arcing,” sending electrical sparks flying inside your microwave and potentially causing fires or otherwise damaging your microwave. A study conducted by the National Fire Protection Association found that from 2011 to 2015, there were an estimated average of 15,970 home structure fires involving microwave ovens per year in the United States.
Paper Coffee Cups With Hidden Plastic Linings
That morning coffee in the paper cup seems harmless enough to reheat, right? Wrong. Even though Starbucks cups are primarily paper, they also contain a plastic liner, wax, and glue. To combat this, companies add plastic liners that hold the liquid inside. Heating a cup with a plastic liner in the microwave is dangerous as the liner could melt, causing physical damage if melted plastic touches your skin or chemical damage if it leaks into your coffee.
Many paper coffee cups have a thin plastic or wax coating on the inside to prevent leaks and maintain the beverage’s temperature. These coatings can melt or warp when exposed to microwave heat, potentially releasing harmful chemicals into your drink. This coating helps keep your drink from leaking, but it can be a problem when heated. When you microwave these cups, the heat can cause the coating to melt, which might lead to harmful chemicals mixing into your drink. Even just a quick 10-15 second stint in the microwave can heat the glue holding your cup together enough for it to start to fail. You’ll have a small leak to deal with at best, and at worst, you could wind up burning yourself with hot coffee.
Cracked, Old, or Discolored Plastic Containers
That trusty old Tupperware container that’s seen better days? It’s time to retire it from microwave duty. Similarly, do not use cracked, old or discolored plastic containers. When plastic containers age, their molecular structure breaks down, making them more likely to leach chemicals when heated. Those cracks and discoloration are signs that the plastic is degrading.
We don’t recommend putting them in the dishwasher because it makes them degrade. The same principle applies to microwave use – heat accelerates the breakdown of plastic materials. Even if a plastic container is labeled microwave safe, it simply means that it won’t melt. It can still contain chemicals like BPA, phthalates or other potentially harmful materials unless it specifically says those aren’t included. When containers are compromised by age or damage, these chemicals become even more likely to migrate into your food.
Cardboard Takeout Boxes With Hidden Dangers
Pizza boxes, Chinese food containers, and other cardboard packaging might seem microwave-friendly since they’re just paper, but they’re loaded with hidden dangers. Unfortunately, cardboard can contain glues, waxes and other materials that can make it a safety hazard in the microwave. Some cardboard takeout boxes even have metal handles or fasteners that can cause sparks and present a fire hazard.
Paper containers should generally not be used in microwaves. For one, some paper containers cannot withstand high temperatures, and exposing them to these conditions can create a fire hazard. Moreover, in paper containers, producers use glue to ensure their structural integrity, and these substances can be released and mixed with food too, which is harmful to your health. Those seemingly innocent takeout boxes are actually chemical cocktails waiting to contaminate your food when heated.
Plastic Containers Without Microwave-Safe Labels
Just because it’s plastic doesn’t mean it’s microwave-safe. The same rule applies to plastic to-go containers that don’t clearly state that it is microwave-safe. Many plastics contain dangerous chemicals that become more active when heated. The two key culprits to dangerous plastics are the man-made chemicals Phthalates and Bisphenol A (BPA), which are often added to plastic to help it keep its shape and pliability. In high volume, these substances have been linked to several negative health outcomes including hormone disruptions, respiratory issues and cardiovascular diseases.
Some of the key endocrine-disrupting chemicals in modern plastics are Bisphenol A, better known as BPA, and a class of chemicals known as phthalates. Both chemicals help to make plastics more durable and sturdy, but they can also interfere with the body’s hormonal communications. BPA in particular is known to mimic the functions of estrogen. As a result, consuming phthalates is associated with health disorders including high blood pressure and cardiovascular disease, while consuming BPA is associated with kidney disorder. Without that microwave-safe label, you’re playing chemical roulette with your health.
Disposable Paper Plates With Plastic Coatings
Those convenient paper plates from your last party aren’t as innocent as they look. While some disposable tableware are coated in a thin layer of plastic. Before you microwave a paper plate or bowl, be sure that it’s clearly marked as microwave-safe. While plain paper plates and bowls are usually safe, some can be covered with a layer of protective plastic to stop them from getting soggy, which can end up in your food. Printed or patterned paper plates and bowls may also have plastics or dyes that create issues.
The problem is that many paper plates have invisible coatings you can’t see. When heated, these coatings can melt and migrate into your food. Microwaving a paper coffee cup can lead to several risks. First, there’s the chance of fire hazards. Paper can catch fire if it gets too hot, and microwaves can create hot spots that might ignite the paper. The same fire risk applies to coated paper plates, especially when they’re heated for extended periods.
Metal-Handled or Metal-Trimmed Containers
Any container with even the smallest bit of metal trim, handles, or decorative elements is a microwave disaster waiting to happen. Before microwaving a paper cup, quickly scan it to ensure there are no metal parts or components. Some paper cups may have metal handles or other attachments, which can cause dangerous situations inside the microwave. If a cup has any metal parts, microwaving is unsafe. This includes containers with metallic paint, gold or silver trim, or metal lids.
Anything made of or containing steel, iron, copper or other hard metals should never go in your microwave. Metal surfaces reflect microwaves, which increases the heat inside the appliance and could lead to a fire. Any takeout container with metal parts, such as aluminum foil or metal lids, should not be placed in the microwave. Metal can create sparks and cause fires. Even tiny metal staples, wire handles, or metallic inks can create dangerous arcing that damages your microwave or starts a fire.
