Why Legal Weed Isn’t Always Safe

Summary

Short Wave (NPR) — "Why Legal Weed Isn’t Always Safe"

Air Date: October 14, 2025
Host: Regina Barber
Guests:

• Theresa Carr, Independent Health and Science Journalist
• Sydney Lupkin, NPR Pharmaceuticals Correspondent

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Overview: The Hidden Risks of Legal Cannabis

This episode investigates the patchwork state-by-state regulation of legal cannabis in the US and highlights emerging health risks from contaminants such as mold, pesticides, and heavy metals. Host Regina Barber is joined by science journalists Theresa Carr and Sydney Lupkin, who share findings from recent investigations about why legal weed isn’t always as safe as consumers might assume. The guests discuss personal stories, regulatory gaps, scientific uncertainties, and practical advice for cannabis users.

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Key Discussion Points and Insights

1. Cannabis Consumption and Unseen Risks ([00:53]–[03:45])

• Personal Story: Theresa Carr shares the case of Summer Parker, an Oklahoma medical marijuana professional with chronic pain, who switched from opioids to cannabis for relief. Summer and her partner experienced unexplained health problems, including fainting and migraines ([01:44]).
• Contamination Discovery: When cannabis products the couple were using were tested, "to their horror, they discovered that they were contaminated with both mold and some pesticides and that those pesticides were associated with some neurotoxicity" (Theresa Carr, [02:56]).

Memorable Quote:
"When they stopped using that weed and switched to another brand, the problems that they had dissipated. So that's all you can say. They feel strongly that the two are correlated."
— Theresa Carr ([05:50])

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2. The Patchwork of State Regulations ([04:20]–[06:59])

• Federal vs. State Oversight: Sydney Lupkin explains, "Weed on the federal level is illegal. Pharmaceuticals… have to be approved by the Food and Drug Administration... With weed, that robust federal system is not there, which means that the states are basically having to figure this all out on their own." ([04:42])
• State Collaboration: States formed a group called CANRA to facilitate communication about regulation, but "the standards are still kind of a patchwork" ([05:22]).

Notable Moment:
Theresa Carr discusses a lab manager in Oklahoma who found that "most [of 20 tested joints] were tainted with mold, two of them actually had salmonella, and about 3/4... overstated the THC level." ([06:21])

• Regulatory Failures: Contaminated products are reaching shelves; regulators struggle to keep products clean ([06:36]).

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3. Testing Incentives and Industry Challenges ([06:59]–[08:48])

• Perverse Incentives: Producers pay for their own product testing, so there's motivation to choose labs with lax standards:
  "Producers will choose labs that are looser about passing products for contaminants, and that will give them higher THC levels. The flip side... labs that are strict about their standards... lose business." — Theresa Carr ([07:08])
• Case Studies—Oregon & California:
  • Oregon opened a state testing lab and cracked down on THC inflation ([08:17]).
  • California’s DCC tracks cannabis from plant to product, but recalls and pesticide issues persist ([08:56]–[09:37]).

Memorable Quotes:
"The labs have sort of had to keep up with this... creative industry where... now we've got THC popcorn on the shelves. Like, how do you test that?"
— Sydney Lupkin ([09:24])

"In 2024, there were over 60 weed recalls, and then this year, they've already had 80 weed recalls, and it's only October, and they've taken 10 actions against laboratories so far this year."
— Sydney Lupkin ([09:58])

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4. National Study: Regulatory Gaps and Scientific Unknowns ([10:14]–[11:40])

• ASU Professor Maxwell Long’s 2022 study found over 600 regulated contaminants across 30 states, but each state tested for only 60–120.
• "A state that might be testing for 300 things might not be testing for the one thing that is guaranteed to give you cancer someday." — Sydney Lupkin ([11:08])
• Research is limited because cannabis remains federally illegal, impeding understanding of health impacts.

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5. Health Concerns: Mold, Metals, and Pesticides ([11:40]–[13:26])

• Inhalation risks are greater than ingestion; contaminants go straight to the lungs and bloodstream ([11:40]).
• Some molds can cause serious lung issues, especially in immunocompromised users.
• Organophosphate pesticides, sometimes found on cannabis, are linked to faster Parkinson’s disease progression—a major issue as "about 40% of Parkinson’s patients use cannabis" ([12:20]–[13:26]).

---

6. Consumer Advice and Harm Reduction ([13:26]–[14:42])

• Best Practices:
  • Buy from licensed dispensaries: Legal products undergo at least some testing.
  • Avoid illicit cannabis: Failed or contaminated products are often sold illegally.
  • Check state recall lists and know local regulations ([13:34]–[14:42]).

Notable Quotes:
"My best advice I can give people, even though it's imperfect, is to go to a dispensary and get a product through the legal market that has been through some sort of testing."
— Theresa Carr ([13:34])

"If you care about the people... growing your weed, it's nice to go legal. And... familiarize yourself with what your state regulations are and... regularly check recall lists."
— Sydney Lupkin ([14:03])

---

Timestamps of Important Segments

• 00:53 — Introduction to episode topic
• 01:11 — Summer & Charles’s story of contaminated weed
• 02:56 — Discovery of mold and pesticides in legal products
• 04:42 — How cannabis regulation differs from pharmaceuticals
• 06:21 — Oklahoma’s widespread contamination findings
• 08:17 — Oregon’s regulatory efforts
• 08:56 — California’s regulatory systems and recall record
• 10:14 — Nationwide study on regulatory inconsistencies
• 11:40 — Why inhaled contaminants are especially concerning
• 12:20 — Health effects: mold, metals, and pesticides
• 13:34 — Advice for consumers
• 14:42 — Episode wrap-up

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Tone & Notable Moments

• The episode balances consumer concern and scientific inquiry, blending real stories (Summer and Charles) with a light, curious tone.
• Lively banter and easy-to-follow explanations help demystify complicated regulatory systems.

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Summary Table: Main Risks Highlighted

| Contaminant Type | Health Risk | Regulatory Issue | |-----------------------|--------------------------------------------------|----------------------| | Mold | Respiratory issues, pneumonia for some users | Not consistently screened across states | | Pesticides (e.g., Organophosphates) | Neurotoxicity, possible link to Parkinson’s | Varying standards, under-researched | | Heavy Metals | Various (depends on the metal) | Inconsistent testing | | Salmonella | Infection risk | Testing lapses detected |

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This episode underscores that while legalization aims for safer access, regulatory, economic, and scientific realities make “legal” weed not always “safe” weed. Consumers are encouraged to buy licensed, tested products and stay informed about recalls and local laws—until federal oversight or better science can catch up.

Transcript

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[B]

Okay, here's the show.

[C]

You're listening to short wave from NPR. Most people in the U.S. now have access to some form of legal weed, but depending on the state, people could potentially be exposed to hidden health risks. Science journalist Theresa Carr did a whole investigation into this.

[D]

I'm really interested at the intersection of science and society.

[C]

Teresa was reporting a story about medical marijuana use when she met Oklahoma resident Summer Parker, a medical marijuana sales and marketing professional who has Ehlers Danlos syndrome, a disorder that affects the connective tissue and often causes serious chronic pain.

[D]

And she became addicted to opioids that were prescribed by her doctor for her pain. And she found that cannabis was both the way to help her overcome that addiction and it also helps assuage her pain.

[C]

But a couple years ago, she and her partner, Charles Arbina, started having unexplained health issues.

[D]

Summer had fainting episodes and stroke like symptoms. Charles, who had a history of migraines, suddenly they became unrelenting. He had to be hospitalized. He lost feeling in the side of his face. The doctors didn't have any real explanation for what was going on.

[C]

When Charles doctor suggested their weed could be contaminated, the couple dismissed it.

[D]

All legal products have to go through a testing process and they get a certificate of analysis, or coa that says it's, you know, free of all these contaminants. And, you know, here's the chemical analysis of it. This is the THC profile.

[C]

And thc, we should say, is short for tetrahydrocannabinol, the chemical responsible for most of cannabis's psychological effects. So in a feature article Teresa wrote for undark.org, she explains that the cannabis plant is good at sucking up things from the environment. Research has shown it could be a tool for environmental cleanup of pesticides and heavy metals. But but this special quality can also bring downsides. For instance, when Summer and Charles got some of the marijuana products they were.

[D]

Using tested, to their horror, they discovered that they were contaminated with both mold and some pesticides and that those pesticides were associated with some neurotoxicity.

[C]

Today on the show, how patchy weed regulations have failed to keep up with consumption and how it could be harming people's health. I'm Regina Barber, and you're listening to Short Wave, the science podcast from npr. This message comes from Charles Schwab. When it comes to managing your wealth, Schwab gives you more choices like full service, wealth management and advice when you need it. You can also invest on your own and trade on thinkorswim. Visit schwab.com to learn more support for.

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[C]

To independent health and science journalist Theresa Carr about patchy weed regulations across the U.S. we also have our own pharmaceuticals correspondent who's reported on this topic as well, Sydney Lupkin. Hey, Sydney.

[B]

Hey.

[C]

So, Sydney, like, marijuana is now legal in some form in many states. What's the difference on how weed is regulated versus, like how pharmaceuticals are regulated.

[B]

In the U.S. yeah, it is super, super different. And that's because weed on the federal level is illegal. Pharmaceuticals, on the other hand, have to be approved by the Food and Drug Administration based on a very detailed process involving clinical trials and inspections to verify safety and efficacy. With weed. That robust federal system is not there, which means that the states are basically having to figure this all out on their own and stand up their own. Many FDA's and many EPAs. And they do have a group that they have sort of formed together called canra, which is basically a way for state regulators to communicate from state to state with one another to share data and what's working and what's not working. But that has its limitations because the standards are still kind of a patchwork.

[C]

Yeah. I mean, this brings us back to Teresa, the story in Oklahoma with Summer and Charles. You know, they got their weed tested with and you said that they Found mold. They found other things. Was it that weed that was causing their health issues?

[D]

There's no way to know for sure. You can't prove cause and effect. One thing they did tell me is that when they stopped using that weed and switched to another brand, the problems that they had dissipated. So that's all you can say. They feel strongly that the two are correlated.

[C]

And this wasn't just a one time thing. In Oklahoma. You wrote in your article about a testing lab, manager, Jeffrey havert, who tested 20 off the shelf marijuana joints there. So what did he find when he did all that testing?

[D]

He found that most of them were tainted with mold and two of them actually had salmonella. He also found that about 3/4 of them, you know, overstated the THC level, which is, as we discovered, fairly common.

[C]

So, Theresa, does that mean that, like, the state's regulatory system for weed in that case failed?

[D]

One could say that. So, you know, there are contaminated products, you know, reaching the shelf. So from that perspective, you can say that the regulatory framework just isn't working to keep all the products that consumers are using and buying at dispensaries to keep those products clean.

[C]

Hmm. Okay. So you reported on how people who produce the weed have to arrange their own testing. Like, how has that affected the industry?

[D]

So I talked to people across the industry, everybody. Growers, lab managers, regulators, activists. And one thing that kept coming up was this issue of perverse incentives that encourage fraud. So you can see that pattern repeated over and over and over again. When a state legalizes marijuana, there's this big rush. A lot of people get into the industry, there's competition, makes things tough. And now at this point, growers are struggling, so they need every single crop to pass. It's very important. Or they go out of business. And generally speaking, their products are going to be much more profitable for them if they have a higher THC level. So the higher THC level, the more it sells for. So producers pay labs to test their products. And my investigation for undoc.org found that producers will choose labs that are looser about passing products for contaminants, and that will give them higher THC levels. The flip side of that is that labs that are strict about their standards are going to lose business.

[C]

You also looked at Oregon's regulations. Why did you look into that state in particular? And what did you learn?

[D]

I was really interested in Oregon for two reasons. One, they had recently opened a state testing lab, which kind of is a new trend among state regulators. So there was that, and there was also their regulatory body had recently cracked down on several labs for THC inflation. In fact, most of their labs in the state they cracked down on for THC inflation. So it seemed a place to go where the regulators were actually taking some action and trying to do something about the problems that we were talking about.

[C]

And, Sydney, you visited California to see how, like, it was regulating its huge weed industry. Like, what's going on there?

[D]

Yeah.

[B]

So state officials had been doing this, like, across several different state agencies. But a few years ago, they consolidated into the dcc, which is their Department of Cannabis Control. And they're basically tracking almost every step in the cannabis pipeline. Like, every plant has a tag and an id, and it gets logged into a database. Like, weed manufacturers even have to report how many pounds of, like, plant trimmings they throw away.

[C]

Wow.

[B]

The labs have sort of had to keep up with this, like, really interesting and, like, creative industry where, like, you know, one day they're like, oh, well, now we've got THC popcorn on the shelves. Like, how do you test that?

[D]

Right.

[B]

And they've got to figure it out. And that isn't to say that DCC is, like, doing everything perfectly, because it's not. There was some reporting by the LA Times that there were still pesticides in the legal weed products, particularly in the vapes. So the department is evolving and trying to respond to that, and it's definitely upped its testing and enforcement in the last few years. So in 2024, there were over 60 weed recalls, and then this year, they've already had 80 weed recalls, and it's only October, and they've taken 10 actions against laboratories so far this year.

[C]

So more testing might mean more recalls, or more recalls may mean more contaminants. We don't know at this point. Let's talk about another study. So, Teresa and Sydney, you both talked to Maxwell Long, assistant professor at Arizona State University, who did a study in 2022 about, like, that patchwork of cannabis regulations. Sydney, what did that report find?

[B]

Yeah, so he said that There were over 600 contaminants that were regulated across the 30 states that had legalized cannabis at that time. But in each state, there were only between 60 and 120 contaminants that were being regulated. So in other words, different states were looking for different contaminants. I also asked Lung, you know, whether states testing for just more contaminants maybe had safer weed, and you said no, because the research about how these contaminants in weed affect your health, you Know, when you inhale them, for instance, it's not really well studied. So a state that might be testing for 300 things might not be testing for the one thing that is guaranteed to give you cancer someday. And a state only testing for a few contaminants might, in fact, be testing for that very bad thing. But without that research, which is hard because weed is still federally illegal, it's really hard to know what the worst contaminants are.

[C]

Yeah. Teresa, is there anything you want to add to that?

[D]

The experts I talk to, including Max, are most concerned with inhaling the contaminants because as opposed to going through your GI tract, this is going. The vape, or the smoke is going directly into your lungs, and then it gets directly into your bloodstream. And when you think about it, like, let's say you're eating an apple, well, you can wash the apple. And if there's anything on it, you know, you can take it at least off the outside, but you don't wash your weed. And we really don't know how those inhaled contaminants are going to get into your system and affect you.

[C]

Wow. Okay. Teresa, you wrote in your article about how these contaminants could affect lungs. Like, how are mold and other things affecting people's health?

[D]

So when you think about mold, it's everywhere. And most forms are fairly harmless, but there are a few forms that can cause serious health problems to humans, especially if you inhale them. And so that's one of the areas experts are most concerned about. And that's the idea that somebody, especially somebody with a compromised immune system, might inhale one of these toxic molds. And there have been case reports of people becoming seriously ill with pneumonia and serious lung respiratory problems from that. The other thing that scientists are worried about are heavy metals and pesticides that are toxic to the nervous system. For example, there is a type of pesticides that's commonly used in cannabis called organophosphates. It's a class of pesticides, and research has linked that to the onset and faster progression of Parkinson's disease, which is really a concern because a lot of Parkinson's, I think something like 40% of Parkinson's patients use cannabis to help with their symptoms of the disease.

[C]

Wow. So. So, Teresa, for consumers, then, who choose to partake, like, is there advice for them that you would give after doing all this reporting?

[D]

So products that don't pass in the legal market are often funneled into the illicit market. So when you buy illicit weed, you may be actually getting something that failed for mold, heavy metals or pesticides. So I, my best advice I can give to people, even though it's imperfect, is to go to a dispensary and get a product through the legal market that has been through some sort of testing.

[B]

Yeah, I, I definitely want to echo that. I talked to a weed cultivator who went from the illegal market to the legal one and he described it as this sort of wild, wild west. And this guy was like, yeah, there used to be, you know, just a guy in a room spraying pesticides with the door closed and, you know, no protective gear. W that just doesn't fly in the legal market. So, you know, if you care about the people who are growing your weed, it's nice to go legal. And then just if you're trying to be safer for you, it's a good idea to familiarize yourself with what your state regulations are and to regularly check recall lists, which are often published online. I think that that would be a good idea.

[C]

Teresa Sydney, thank you so much for talking with me today. Thank you.

[D]

Thank you.

[C]

This episode was Produced by Burleigh McCoy, edited by Viet Le, and fact checked by Tyler Jones. The audio engineer was Robert Rodriguez. Beth Donovan is our senior director. I'm Regina Barber. Thank you for listening to Short Wave from npr.

[A]

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