Delta-8 THC is a newly popular way to get high, since it’s legal in many places where regular cannabis isn’t. But just because it has slipped through a legal loophole doesn’t mean it’s perfectly safe, and recently the Food and Drug Administration and the Centers for Disease Control and Prevention warned consumers and health providers about some potential downsides.

What is delta-8?

Cannabis contains a variety of naturally occurring chemicals that have effects on our brains and bodies. The best known is tetrahydrocannabinol, or THC. That’s considered to be the main source of weed’s high. Technically most THC that we care about is known chemically as delta-9 THC, and federal regulations apply to cannabis plants that have a certain percentage of delta-9.

Another of these natural chemicals is cannabidiol (CBD), which you’ve probably noticed is everywhere since the 2018 Farm Bill allowed cannabis plants with less than 0.3% THC to be sold legally. This means that if you start with low-delta-9-THC hemp plants rather than high-delta-9-THC marijuana, you can make just about anything you like and sell it legally. This led to the boom in CBD products, which are made from these low-THC plants.

Somewhere along the line, some genius figured out that you could process hemp plants to create delta-8 THC. This isn’t prohibited by federal law, but it can still make you high. There’s more info on this in our guide to enjoying delta-8 responsibly, but basically, in most states you can easily buy delta-8 products over the counter or order them online. You’ll often find them in CBD shops, since they owe their availability to the same legal loophole.

What’s wrong with it, then?

The FDA’s and CDC’s recent warnings don’t include anything too dire about delta-8 itself, but we’ll get into the specifics in a minute. What’s important to know first is that delta-8 is still THC, and it seems to have similar risks and benefits as normal (delta-9) THC.

In other words, it can get you high, and if you take too much, you could get the symptoms of “greening out” including being nauseous, lethargic, and uncoordinated. THC can also affect your heart rate and blood pressure, making it a health concern even though overdoses are unlikely to ever be fatal.

Once you understand that, there are two main issues that the FDA and CDC are worried about.

People don’t always realize they’re taking THC

Since delta-8 is often sold alongside CBD products, it may be easy to miss the fact that you’re buying something that can get you high. Not everybody knows what delta-8 is, and those who are being introduced to it for the first time might hear it being called a cutesy nickname like “diet weed” or they might hear a sales pitch downplaying the similarities between delta-8 and normal weed.

The recent CDC report mentions two cases from the West Virginia poison control center in which adults took what they thought were “CBD-like products” and ended up getting high enough to call the poison control center.

Another pair of cases, this time from Michigan, were in children who ate a parent’s delta-8 gummies. The children ended up with slowed breathing, slowed heart rate, and lowered blood pressure. They were admitted to intensive care for monitoring and supplemental oxygen.

The CDC also notes that labels may not always reflect how high a product can make you feel, since there are cases where a weed product might contain both delta-9 and delta-8, but only list the one or the other on its label. And while states with legal weed often have some oversight of quality control or requirements for lab testing, there’s no such framework for delta-8 products.

The bottom line here is that it’s important to treat delta-8 items the same as you would any other weed product: Keep them away from children and pets, read labels carefully, and when you try any new product, take a small dose to start with.

Delta-8 products could be contaminated with other chemicals

If delta-8 products only contained delta-8, that would be the end of it. But hemp plants don’t contain much delta-8 normally; that’s why we’re talking about delta-8 products (like gummies and vapes) rather than just smoking hemp flowers. It takes a lot of industrial processing to turn the trace cannabinoids in hemp into enough delta-8 for a psychoactive gummy.

As an article in Chemical and Engineering News explains, laboratory analysis has found other cannabinoids like delta-9 and delta-10 THC in many delta-8 products, as well as a menagerie of mystery compounds that don’t occur naturally in cannabis and whose effects and potential risks are still unknown. One of these is olivetol, which might blunt your high and might be the reason why people often feel lighter effects from delta-8 than regular cannabis—but that’s just a hypothesis. We also don’t know what a safe dose of olivetol might be.

Then there’s the issue of what gets added to the products as the delta-8 is being produced. Usually there is a solvent like toluene or heptane, and a strong acid. That might be okay if you knew for sure that those chemicals were removed before the product was finished. But “most people are not actually taking the time to distill it or use chromatography,” a chemist told Chemical and Engineering News.

The FDA and CDC are also concerned that people making delta-8 products may be doing it without proper facilities, and that they may be adding ingredients for color or other reasons that may not be safe to inhale or ingest. If you recall the vaping-related lung disease (EVALI) of a few years ago, that seemed to have been caused by additives in weed vapes that were not safe to inhale. Regulation doesn’t automatically make things safe, but it’s worth noting that none of the vape products linked to EVALI were from legal dispensaries.

If you think you’ve had health problems related to a delta-8 product (or to any medication, for that matter), the FDA has a number of ways to report those and even to speak to a person at the agency directly, which are listed at the bottom of their fact sheet on delta-8.