Safety in the use of plastics has been a long standing concern for many people. As someone closely working with this industry I can definitely clear some things up for you.

First of all, there is no general term called "plastic poisoning", I assume you are referring to dangerous chemicals or what innumerable forwards may have warned as carcinogens  that can enter your food and poison you and give you long term health risks. That is partially true but only half the story. There are many safe and unsafe plastics out there with each plastic typically having very specific use cases in the industry.

Coming to bottles - Plastic Bottles come in many MANY varieties, including (in order of most commonly found): (Note, in terms of plastics, there are many other grades as well, but not commonly used in bottles or food storage and I have chosen to ignore them for this answer)

1. PET - Poly Ethylene Terapthalate

This is easily the most commonly used material. Think of your coca cola bottles, bottled water, and nearly every commercialized beverage. That is a standard PET bottle. PET has been around for many decades now and while it is largely very safe to use, it should be noted that most PET products are only Food Contact Safe vs. Food Grade. Food Contact safe is usually a term to indicate that there are absolutely no known issues for the expected shelf-life + expected consumption period of that product and not for perpetual use.

My suggestion would be to avoid storing and using these as you can definitely find better/safer alternatives out there. Its usually a standard household habit to re-use 2L or other bigger PET bottles for regular home use once the beverages are empty - avoid it if you can!

Also, its quite possible that you have received many forwards on e-mail or whatsapp/[your favorite messenger/social media platform here] about the dangers of drinking water left in the car, etc. Those are usually in reference to PET bottles, bevause they are not very stable in high heat conditions, or in presence of UV. They can partially degrade and leech chemicals (extremely small traces) into the contents of your bottle.