Hemp Material Limits: What You Need To Know About Pesticides, Solvents, Heavy Metals, and Microbiological Contaminants

5 mins read
Exploring A CBD Certificate of Analysis:  Part 4 of a Series

Hemp Material Limits:

What You Need to Know About Pesticides, Solvents, Heavy Metals, and Microbiological Contaminants

CBD comes from the hemp plant—a product of the earth, grown with modern agricultural practices. As with any plant, some of the substances hemp comes in contact with as it’s grown, harvested, and processed can end up in the CBD that’s extracted from it. That includes residues from pesticides, heavy metals from soil or fertilizers, or traces of solvents that may have been used in the extraction process.

While that might sound a little scary, it’s all part of the complex landscape of working with hemp, and indeed, all cannabis products. Reputable CBD companies know to look for these issues, and to test their products at all stages of production to verify that their finished products are safe from these contaminants. These test results should always be reported in a Certificate of Analysis (COA).

We’re committed to following the highest possible safety standards when we produce our Caliper CBD, and confirm it with third-party testing by accredited, third-party labs. But you don’t have to take our word for it; you can see the results for yourself, in the “Hemp Material Limits” section of our COA.  Here’s what you’ll find there, and some background on what the results mean.


What are they? Pesticides are substances used to manage common problems in growing plants. They include herbicides to fight weeds, insecticides for managing insects, or fungicides to prevent molds or mildew. Most cannabis producers incorporate some kind of pesticide to manage their crops, including some approved for organic use.

Why do they matter? If not used carefully, pesticides can cause harm to the environment and are linked to a wide range of human health problems, including increased cancer risk and endocrine system disruption.The U.S. Environmental Protection Agency (EPA) regulates pesticides with strict rules for their agricultural use.

How do they get into CBD? Currently, the EPA allows the use of 10 different pesticides for hemp production, with guidelines to prevent environmental damage and human health risks. But pesticide residues can linger on hemp if they’re not carefully applied—say, oversprayed, or applied too close to harvesting—or if pesticides “drift” over from a neighboring field.

How do we ensure that our products avoid pesticide contaminants? All our hemp is responsibly grown in the U.S. We require all our suppliers to provide third-party testing verification that they’ve met the “gold standard” for stringent pesticide regulation: California’s Code of Regulations for pesticide limits—and we also test our finished product, Caliper CBD, to make sure it meets those requirements.

Residual Solvents

What are they? Solvents are chemicals used in the manufacturing processes that extract cannabinoids, terpenes, and other compounds from hemp material. They include compounds like propane, butane, isopropanol, hexene, and acetone.

Why do they matter? Many solvent compounds can be harmful to the body in significant amounts. For example, benzene is a carcinogen, and butane has been associated with heart damage.

How do they get into CBD? Solvents usually evaporate completely after the compounds are removed from the plant material, but there’s always a chance that some might remain (“residual” solvents) in your CBD. While it’s only a small amount, the exposures could add up if you’re taking CBD regularly.

How do we ensure that our products avoid residual solvent contaminants? To ensure that the CBD we work with is safe, we require that our CBD suppliers test for a full suite of known residual solvents, using accredited third-party labs. The test results must conform to the limits set by one of the nation’s most rigorous standards: Colorado’s Statute 1 CCR 212-2.

Heavy Metals

What are they? Heavy Metals are metallic elements widely found in the environment. They naturally occur in our soils, but can also come from pollution generated by manufacturing, vehicle emissions, mining, agriculture, and other industrial sources.

Why do they matter? While we actually need small amounts of some heavy metals like zinc and chromium, others can be toxic, and cause significant harm if they build up in the body. Lead, mercury, arsenic and cadmium are some of the most common causes of heavy metal toxicity.

How do they get into CBD? Heavy metal contamination can occur if hemp is grown in soils that contain heavy metals or has been treated with certain fertilizers. The hemp plant is very susceptible to this kind of contamination, because it’s what plant scientists call a bioaccumulator—it absorbs heavy metals from soils and water through its root system. In fact, hemp is sometimes used to clean up toxic waste sites.

How do we ensure that our products avoid heavy metal contaminants? At Caliper we believe that because hemp is a bioremediator, we must be extra conservative when it comes to setting heavy metal standards. We require our suppliers to meet the strictest state regulations for heavy metal content: Colorado’s and California’s codes of regulations. Our guidelines are even tighter, cutting acceptable levels in half. For example, Colorado’s regulation for lead levels allows <1000 parts per billion (ppb). We require our suppliers to meet a goal of <500 ppb.

Microbiological Results

What are they? Organisms such as molds, yeasts, and bacteria, which are ubiquitous throughout our environment.

Why do they matter? While most microbiological organisms are harmless (and indeed, critical to a healthy environment and to human health), harmful contaminants such as E. coli 0157:H7 and Salmonella, and other Enterobacteriaceae bacteria, as well as Listeria monocytogenes have been associated with dangerous foodborne illnesses.

Going beyond the issue of causing illness, monitoring microbial contaminants is an important measure of how carefully your CBD product is made. Microbial test results are your assurance that rigorous food safety and manufacturing standards are being used. If a company doesn’t conduct microbial testing and/or doesn’t share the results publicly, you shouldn’t buy their products.

How do they get into CBD? Like any living organism, hemp can pick up molds and bacteria while it’s growing, being harvested, and stored. And, when hemp is processed to make CBD, other organisms can be introduced if proper handling and manufacturing procedures aren’t followed. For example, if employees don’t practice careful hygiene such as hand washing, enterobacteriaceae can be transmitted. Air quality in production facilities must be carefully monitored to prevent transmission of airborne pathogens such as molds or yeasts.

How do we ensure that our products avoid microbiological contaminants? All our products are manufactured in a GMP-certified facility. GMP stands for “Good Manufacturing Processes”–the food industry’s leading procedures for producing safe food products. Our experienced food safety professionals employ rigorous, comprehensive microbial testing protocols that include yeasts, molds, Enterobacteriaceae including E coli 0157:H7 & Salmonella, Listeria monocytogenes and aerobic bacteria. Our microbiological testing is provided by Eurofins Microbiology Laboratories, a world leader in food, environment and pharmaceutical products testing.

The Caliper Standard of Safety

As you can see, we take safety very seriously at Caliper. It starts with following the best-known standards for protecting consumers:The FDA’s guidance for food safety and safe food production, monitoring and labeling. We also make it our policy to meet, and often exceed, the strictest state regulations for hemp sourcing, monitoring and certification. Lastly, we’re committed to rigorous testing to confirm safety, using only accredited laboratories–and reporting the results, with full transparency, in our COA. We know you’re careful about what you put into your body, and we are too.

Be informed.

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