Are you able to microwave plastic? – Healthline


Plastic is a synthetic or semi-synthetic material that is durable, light and flexible.

These properties enable the manufacture of a wide variety of products including medical devices, auto parts, and housewares such as food storage containers, beverage containers, and other tableware.

However, you may be wondering if you can safely put plastic in the microwave to prepare food, reheat your favorite beverage, or reheat leftovers.

This article explains whether you can safely microwaveable plastic.

Plastic is a material made up of long chains of polymers that contain several thousand repeating units called monomers (1).

While they’re usually made from oil and natural gas, plastics can also be made from renewable resources like cellulose and cotton liner (1).

At the base of most plastic products there is a recycling triangle with a number – the resin identification code – between 1 and 7. The number indicates what type of plastic it is made of (2).

The seven types of plastics and products made from them include (2, 3):

Polyethylene terephthalate (PET or PETE): Soda drink bottles, peanut butter and mayonnaise jars, and cooking oil containersHigh density polyethylene (HDPE): Detergent and hand soap containers, milk jugs, butter containers and protein powder pansPolyvinyl chloride (PVC): Piping, electrical wiring, shower curtains, medical tubing and artificial leather productsLow density polyethylene (LDPE): Plastic bags, squeeze bottles and food packagingPolypropylene (PP): Bottle caps, yoghurt containers, food storage containers, coffee capsules for one serving, baby bottles and shaker bottlesPolystyrene or Styrofoam (PS): Packaging of peanuts and disposable food containers, plates, and disposable cupsOther: includes polycarbonate, polylactide, acrylic, acrylonitrile butadiene, styrene, fiberglass and nylon

Some plastics contain additives to achieve the desired properties in the end product (3).

These additives include colorants, reinforcements and stabilizers.


Plastic is mainly made from oil and natural gas. There are several types of plastics that have a wide variety of uses.

The main problem with microwave plastics is that additives – some of which are harmful – can get into your food and beverages.

The top chemicals of concern are bisphenol A (BPA) and a class of chemicals called phthalates. Both are used to increase the flexibility and durability of plastic.

These chemicals – especially BPA – disrupt your body’s hormones and have been linked to obesity, diabetes, and reproductive harm (4, 5, 6, 7).

BPA is mainly found in polycarbonate (PC) (number 7) plastics, which have been widely used to make food storage containers, drinking glasses and baby bottles since the 1960s (8).

The BPA from these plastics can get into food and beverages over time, as well as when the plastic is exposed to heat, e.g. B. when it is cooked in the microwave (9, 10, 11).

However, some manufacturers of food preparation, storage and serving products have now replaced PC plastic with BPA-free plastic such as PP.

The Food and Drug Administration (FDA) also bans the use of BPA-based materials in infant formula, drinking cups, and baby bottles (8).

However, studies have shown that even BPA-free plastics can release other hormone-disrupting chemicals such as phthalates or BPA alternatives such as bisphenol S and F (BPS and BPF) into food in the microwave (12, 13, 14, 15).

Therefore, it is generally a good idea to avoid microwave plastic unless the container is specifically labeled as safe for use in the microwave according to the FDA (16).


Microwave plastic can release harmful chemicals like BPA and phthalates into your food and beverages. So avoid microwave plastic unless it’s labeled for that particular use.

While microwave plastic speeds up the release of BPA and phthalates, it’s not the only way these chemicals can get into your food or beverages.

Other factors that can increase chemical leaching are (14, 17):

Placing food in plastic containers that are still hot scrub containers with abrasive materials like steel wool that can scratch if containers are used for long periods of time and the containers are repeatedly exposed to the dishwasher over time

Plastic containers that are cracked, pitted, or showing signs of use should usually be replaced with new BPA-free plastic containers or containers made of glass.

Today, many food storage containers are made from BPA-free PP.

You can identify PP containers by looking for the PP stamp below or a recycling sign with the number 5 in the center.

Plastic food packaging, such as adhesive plastic wrap, can also contain BPA and phthalates (18).

If you need to cover your food in the microwave, use waxed paper, parchment paper, or a paper towel.


Scratched, damaged, or excessively worn plastic containers pose a higher risk of chemical washout.

Plastics are materials made primarily from oil or petroleum, and they have a wide variety of uses.

While many food storage, preparation, and serving products are made from plastic, microwaves can accelerate the release of harmful chemicals such as BPA and phthalates.

Therefore, if the plastic product is not classified as microwaveable, avoid microwaving it and replace worn plastic containers with new ones.

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