How you smoke is just as important as what you smoke. In today’s increasingly marijuana-friendly world, more and more people are turning to cannabis as both holistic medicine and a healthy way to get buzzed. But it doesn’t matter if you’re buying the highest quality organic hydroponic herb if you’re smoking it wrong. The dangers of smoking out of plastic pose a serious health threat. Here’s why you should pay more attention to how you’re lighting up.

Most types of plastic are dangerous.

Many plastics can cause cancer. There are seven kinds of plastics according to The Society of Plastics Industry, each with a different level of toxicity to humans. Categories 1 (polyethylene terephthalate) which includes BPA, 3 (polyvinyl chloride), and 6 (polystyrene) are the most carcinogenic. This means that they pose the greatest health risk.

The plastic you use every day in water bottles is no exception.

This first category, polyethylene terephthalate, includes everyday items such as water bottles, and other things generally intended for single use. Think of the taste of water from a plastic water bottle left sitting in a hot car. It tastes likes chemicals because chemicals have leached into the contents of the bottle.

According to Cancer Research UK, plastic bottles heated up to 60⁰C contain unhealthy levels of toxic chemicals. Imagine what can leach into your system when you smoke from a homemade water bottle bong where the bottle is routinely heated up.

Recently, the press has focused a lot on BPA, which resembles polyethylene terephthalate. BPA is found in many reusable plastic water bottles. BreastCancer.org describes BPA as a synthetic estrogen. Because estrogen is a hormone, BPA can disrupt your body’s hormone levels, making you more susceptible to cancer.

This is especially the case with breast cancer. Another disturbing side effect of BPA consumption for women is that it can affect a baby’s development. The presence of this synthetic estrogen leads to the birth or more girls than boys, and many of these babies suffer from depression and anxiety.

If these are the health risks of drinking water from a water bottle, imagine the dangers of smoking out of plastic.

The plastic found in animal toys, plastic wrap, takeout containers and Styrofoam is also a carcinogen.

Categories 3 and 6 according to the Society of Plastics Industry are equally dangerous, and equally common, as those in Category 1. According to the EPA, polyvinyl chloride, commonly used in pipes, packing material, homewares and new cars can cause liver cancer and disrupt the human nervous system.

You can come into contact with polyvinyl chloride by drinking water that came from pipes coated with this chemical.

Category six is also carcinogenic. It includes Styrofoam, which is the brand name for plastic chemical polystyrene. This plastic is so toxic that New York City prohibits the use of containers with polystyrene.

Whenever you smoke out of low quality plastic bongs manufactured in countries with little to no health regulation, you put yourself at risk for ingesting these sorts of chemicals.

Final Hit: The Dangers of Smoking Out of Plastic

Today, the dangers of smoking out of plastic are often uncertain, but that doesn’t make them any less alarming. This is true whether you’re using a water bottle or other plastic container as a homemade water pipe or a store bought plastic bong with unknown ingredients.

Our country and many others do very little to ensure the safety of plastics. The only safe way to avoid ingesting carcinogens is to avoid plastic whenever possible.

But no need to fret. The best bongs and one-hitters are silicone or glass anyway. Make sure to give your health—and your herb—the attention it deserves.