Our world is full of plastic. From everyday objects to toys to furniture to cups, bowls and plates, we interact with man-made, plastic materials constantly.

Along with the recent green movement came the push to avoid using plastic objects for drinking, including straws and plastic bottles. Not only are these bad for the environment, but they could potentially put your health at risk due to their chemical makeup.

However, sometimes convenience and necessity require us to use plastic bottles for drinking. In that case, it’s important to understand the different types of plastic, what they mean for your health and which are the safest to drink from.

The risks of plastics

Drinking and eating out of plastics can come with some risks, especially when you’re using certain types of plastic. You can tell what kind of plastic you’re using by looking for a number inside a triangular arrows symbol on the item.

Toxic chemicals

Among the biggest dangers of plastics are the harmful chemicals present in certain plastic types. Studies have shown that certain toxic chemical compounds can leach out of the bottles and into the food or drink they are holding.

This danger is particularly prevalent when certain plastics are heated, such as in a microwave or dishwasher. Heat is not necessary, though. Many types of plastics will leach chemicals into the liquids or foods they hold over time.

One such man-made chemical is Bisphenol A, or BPA. It is believed that long-term exposure to BPA may have health consequences for both humans and animals, including potential hormonal disruption and brain development problems when exposed to fetuses or infants.

BPA is particularly common in type 7 plastics, or polycarbonate. This type of plastic is extremely durable and common in reusable water bottles.

Another dangerous chemical compound is phthalates. These compounds are endocrine disruptors, meaning they are known to interfere with hormones. Phthalates are additives to plastics that make them flexible, and they are not commonly found in drinking bottles, but still may appear in certain plastic objects.

Other dangers

In addition to the clear presence of chemicals like BPA and phthalates, some plastics come with other risks. Certain plastics are generally safe to use once but not multiple times. Multiple uses can allow the plastic to leach out other chemicals. These bottles are usually marked with a “1” and are made of polyethylene terephthalate, or PET.

Additionally, plastic is a known host for bacteria—particularly in ribbed single-use water bottles. The nooks and crannies in your water bottle can be the perfect place for harmful bacteria to thrive and potentially make you sick. All reusable bottles should be washed with hot water and soap, and single-use bottles should be recycled after their first use.

Safe plastics for drinking

Even with these concerning risks surrounding plastic, you don’t have to swear off all plastic for fear of your health. There are plastics that are generally safe to drink out of.

Identify which plastics are which by looking at the identification number, which is usually designated on the bottom of the container. Some bottles will even include “BPA Free” or messages stating they are free of other chemicals on them in writing. Most bottles meant for drinking will be labeled #1 or #7.

The following plastic types are generally safe to drink out of.

• Type 1: Polyethylene Terephthalate (PET): Most water and other drinking bottles are made out of this plastic. It is generally safe, but typically only for a single use. Subsequent reuses may allow PET to transmit more chemicals, including antimony, into the contents—especially if the bottle is heated. Because of the single use component, these bottles may be safe for your health, but not the environment.
• Type 2: High-Density Polyethylene: This plastic is rigid and typically used for more structured bottles like detergent and soap. It does not contain any known human carcinogens or other harmful chemicals.
• Type 4: Low-Density Polyethylene: This plastic is quite flexible and usually used for plastic wrappings and bags instead of bottles. It does not contain harmful chemicals.
• Type 5: Polypropylene: This plastic is hard and flexible and is typically used both for plastic linings and things like buckets. It will not leach harmful chemicals into the food or liquid it contains.
• BPA-free type 7 bottles: Although “7” is usually used to denote polycarbonate, which contains BPA, it can also denote other plastics that do not contain BPA. Manufacturers of reusable type 7 water bottles will write “BPA free” on the bottle if the plastic does not contain BPA. These types of bottles are generally safe.

Overall, numerous types of plastics can be generally safe to drink from. With that said, however, it’s both responsible for the environment and cautionary for your health to opt to use other types of bottles, such as those made from glass or stainless steel, when drinking water and other beverages each day.