Lawn Safety | Beware of These Potentially Harmful Chemicals


May 29, 2020

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Whether it’s an herbicide to kill those nutrient-sucking weeds, an insecticide to rid your turf of nasty insects, or a fungicide to prevent disease-causing fungi, pesticides are an important part of turf maintenance.

The thing about pesticides is while their active ingredients do a great job killing off unwanted insects, weeds, and fungus, they can also harm humans. What’s more, increased use can increase the risk of long-term negative effects.

You can prevent short- and long-term effects by knowing how to identify the active ingredients in a pesticide, their toxicity levels, and potential effects. Wearing the proper personal protective equipment helps too.

Below, we’ll cover all this and more so you can kill those pests without hurting yourself or others.

How to Find the Active Ingredients on Products

The first step to understanding just how much harm a lawn care product can do is knowing what its active ingredients are. Much like food and medicine, pesticide manufacturers must put their products’ active ingredients in a conspicuous place on the packaging.

You’ll generally find this list on the front or back of the packaging. It’ll be marked clearly with the headline “Active Ingredients.” Sometimes, there’s only one ingredient on this list, but there can also be several, depending on the product. This list should also show what percentage of the product is made up of each active ingredient.

These active ingredients can help in multiple ways. First, they help you determine if a particular product is safe to use on your lawn and if it’ll work on the issue you’re having. More importantly, it’ll tell you what potentially toxic or harmful chemicals the product contains.

Keep in mind, though, there are potentially even more harmful chemicals not listed on the active ingredients list. There can be other chemicals that act as delivery mechanisms or are byproducts of its manufacture and won’t appear as an active ingredient but may cause harm.

You can find out just how toxic a product is on its label, as all pesticides must carry one of four warnings:

  • “Danger-Poison”: This indicates toxicity category I, which is the highest and means it’s fatal if ingested.

  • “Danger”: Again, this is a toxicity category I, but indicates it’s highly corrosive to eyes and skin.

  • “Warning”: This indicates toxicity category II, which is moderately toxic.

  • “Caution”: This is Toxicity category III or IV, which is the least toxic.


Fertilizers are great for greening up your lawn and helping keep it looking in tip-top shape through even the roughest of conditions. To humans, though, some fertilizers pose a big risk due to the chemicals in them — even the inactive ones.

Toxic Inactive Ingredients in Fertilizers

Some inorganic fertilizers are manufactured from recycled waste products, which often leaves them containing high levels of various harmful chemicals. These chemicals may include zinc, lead, cadmium, chromium and arsenic — yes, that arsenic.

While these chemicals may not be listed in the active ingredients because they aren’t what make the fertilizer function, you must be aware of their potential presence.

Some of the harmful side effects of these chemicals include cancer, liver disease, and kidney damage from the lead and cadmium; reproductive harm from cadmium; infant deformity from the lead; and cancer, liver disease, coma, or even death from arsenic.

Active Ingredients Cause Harm Too

In the list of its active ingredients, fertilizer will generally include phosphorus and nitrogen, which can also be harmful to humans. If ingested, nitrates can prevent oxygen from binding with hemoglobin, inhibiting the flow of oxygen through the body.

Generally, this ingestion comes from drinking contaminated water due to runoff, but you may also ingest it if you have fertilizer on your hands while eating.

Though phosphate is a chemical humans need, too much has its health risks, including kidney damage and osteoporosis. It is also harmful to fish and other wildlife due to runoff into lakes and streams.

Weed Killers

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Herbicides help keep our lawns free of unsightly weeds and our driveways and walkways clear of rogue grasses and dandelions. While many use active ingredients that cause little to no harm to humans, others can lead to serious illnesses or even death.


2,4-D is a common herbicide for tackling broadleaf weeds and does quite fine work at its intended function. But, it also has the widest range of serious side-effects on our list. These side-effects include cancer, endocrine problems, reproductive issues, brain damage, kidney and liver damage, skin irritation, and birth defects.


Benfluralin is a pre-emergent herbicide to control various types of weeds like chickweed, purslane, knotweed, and others. Its toxicity is relatively low, but it’s been known to cause kidney and liver damage and eye and skin irritation.


Bensulide is a selective herbicide used in gardens and on turfgrass to control a wide range of unwanted grasses and broadleaf weeds. Its toxicity levels are relatively low, but acute exposure through ingestion can cause convulsions, nausea, vomiting, abdominal cramps, incoordination, slurred speech, coma, and even death.

Chronic exposure can have longer-term neurological impacts, chest tightness, nausea, abdominal cramps, diarrhea, headache, dizziness, weakness, loss of muscle coordination, and face muscle twitches.


Clopyralid is used in post-emergent herbicides to control legumes, composites, and other broadleaf weeds.

While its toxicity is relatively low, it can cause eye irritation or even permanent vision loss if it contacts your eyes. Clopyralid has also been linked to reproductive system issues and birth defects.


Dicamba is generally used on weeds that have become tolerant to glyphosate, which is why it’s sometimes combined with glyphosate in some herbicide blends. Its toxicity is relatively low but worthy of a mention.

When inhaled, dicamba can cause dizziness and nasal irritation. When it contacts the skin, it may also cause irritation. Ingesting dicamba may result in vomiting, muscle spasms, loss of appetite, diarrhea, and abdominal pain.

There have been weak links made between dicamba and lung and colon cancer, but no hard research has turned up a direct link.

Diquat Dibromide

Diquat dibromide is a common contact herbicide that while only mildly toxic is still worth discussing. Overexposure to this active ingredient can result in kidney and skin damage. It can also lead to fingernail softening or loss, cornea scarring, and nosebleeds.


Fluazifop-p-butyl may have a funny-looking name, but its toxicity is no laughing matter.

While it has no noted chronic impacts, according to Cornell University, its acute risks include severe stomach and intestine disturbance, drowsiness, dizziness, loss of coordination, and fatigue when ingested.

Breathing Fluazifop-p-butyl may cause vomiting and severe lung congestion, which can lead to labored breathing, coma, and, in some cases, death.

Contact with the skin or eyes can cause mild irritation.


Likely the most infamously toxic weed killer as of late is Monsanto’s Roundup. The issue behind this weed killer and many others is mainly its active ingredient glyphosate.

While experts have known since 2015 that glyphosate is a potential carcinogen, it’s also been noted that Roundup’s mixture of glyphosate and other chemicals enhances its toxicity.

That said, there has been some debate over the toxicity and cancer-causing impact of glyphosate. The Environmental Protection Agency says it doesn’t cause cancer, but the World Health Organization, multiple lawsuits, and several juries have said differently. This lends more credence to the belief it’s more Roundup’s proprietary mixture than the Glyphosate alone causing the issues.


Imazapyr is a relatively common nonselective herbicide you can use as a pre- or post-emergent weed control. It’s also approved as an aquatic herbicide, killing pond-dwelling weeds without many adverse effects on marine life.

For humans, imazapyr has mild acute toxicity that can lead to light skin irritation upon contact or mild illness if ingested. Where its danger is the highest is eye contact, as it can cause irreversible damage to your eyes.


Isoxaben is a useful pre-emergent herbicide used on broadleaf weeds, grasses, and vines. Most users apply it to the areas surrounding ornamental trees and shrubs. Isoxaben has a low toxicity rating, but it’s known to cause mild skin or eye irritation on contact.

In studies, the long-term impact of isoxaben has been linked to enlarging organs and reproductive problems in some animals. In humans, though, it’s been deemed mostly harmless to reproduction and long-term health.


MCPA is another herbicide that works well against annual and perennial weeds but also has a darker side.

According to Cornell University, MCPA’s acute toxicity is relatively minor, but long-term exposure can cause more serious chronic issues like enlarged kidneys, reduced reproductive function, cell mutation, anemia, muscular weakness, stomach and liver issues, and more.

Fortunately, MCPA is a restricted-use pesticide (RUP), so only certified professionals can purchase and apply it.


Mecroprop — also known as MCPP — controls creeping broadleaf weeds like chickweed, lambsquarters, ivy, and others.

MCPP’s acute toxicity risk is relatively low. Most subjects experience eye and skin irritation, and cloudy vision.

In higher doses and long-term exposure, MCPP has more pronounced impacts. These may include birth defects and intrauterine death, cell mutation, kidney damage, and endocrine issues. There is also anecdotal evidence of soft-tissue cancer, according to Cornell University, but no hard data to back it up.


Paraquat is another popular active ingredient in herbicides that can be extremely harmful. Small exposure to or inhalation of paraquat can lead to lung damage, heart and kidney failure, Parkinson’s disease, and eye damage. Larger exposures and ingestion can lead to death.

Pelargonic Acid

This naturally occurring acid also works as a great nonselective post-emergent burn-down herbicide. It kills unwanted plants more rapidly than most, as plants start showing damage as soon as 15 minutes after application and begin to collapse in as little as one hour.

Despite being such an effective killer, it’s relatively harmless to humans. It’s not known to cause cancer or any other serious issues, even if ingested. It is, however, a skin and eye irritant, so it still carries a “Warning” label.


This selective herbicide helps control annual grasses and some broadleaf weeds. It’s useful as either a pre-emergent or post-emergent weed killer.

Its toxicity isn’t alarming but worth noting. Acute toxicity includes mild skin and eye irritation on contact and mouth, nose, throat, and lung irritation if inhaled. As for longer-lasting issues, chronic exposure to pendimethalin in studies has shown reduced birth weight. It remains unknown if there is any relation between pendimethalin and cancer, but the EPA is currently testing for a connection.


Triclopyr is a very common selective herbicide used to battle broadleaf weeds. It often combines with other herbicides, like 2,4-D and clopyralid.

In animal testing, this chemical has mild toxicity, including skin and eye irritation, and fetal development issues. In human testing, though, only skin and eye irritation were observed. There were no reproductive impacts, nor was it found to cause cancer.

Insect Killers

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You’ll find insecticides can be found virtually everywhere and are nearly unavoidable. From the air we breathe to the food we eat, we take in plenty of these toxins in normal day-to-day life. There’s no need to increase our exposure when doing our lawn care.

Here are some of the toxic chemicals found in insecticides, and the damage they can cause.


Acephate was once a common insect killer in the home, but most household uses have been banned today. It remains a powerful insecticide for food crops and turf, though.

While it’s effective at mitigating biting and sucking pests, there are some mild side effects to using it. Acute exposure to Acephate may cause nausea, diarrhea, cramping, shaking, swelling, rapid heart rate, dizziness, and disorientation within minutes or hours of exposure.

Studies have also linked Acephate to lower reproductive rates and has shown its toxicity to fetuses. Other than the reproductive issues, there are no other proven chronic issues noted from Acephate exposure, but it is classified as a “possible human carcinogen” due to the liver and adrenal gland tumors found in test animals.


Bifenthrin is a broad-use insecticide that can kill a wide range of flying and crawling insects.It is a restricted-use pesticide (RUP), so only certified applicators can purchase and use it.

Despite being an RUP, its toxicity is relatively minor. Upon contact with the skin, it can cause tingling, itching, burning, or numbness at the site of contact. Inhaling it can cause nose, throat, and lung irritation. Ingesting large amounts of bifenthrin may cause immediate throat and abdominal pain, and vomiting.

As for long-term effects, the EPA classifies it as a “potential carcinogen” based on a study with mice.


Carbaryl is a popular outdoor-use-only insecticide used to kill aphids, fire ants, fleas, ticks, spiders, and others.

Despite lacking a restriction on its use, carbaryl is considered moderate to very toxic. It can cause skin burns upon contact. Inhalation can cause nerve and respiratory problems resulting in nausea, stomach cramps, and more. In higher doses, it can cause sweating, blurring of vision, incoordination, and convulsions.

Though the proven risk of long-term negative impacts from using carbaryl are low, the EPA says it’s “likely carcinogenic” to humans due to studies on rats.


Fipronil is a common insecticide to help control ants, beetles, cockroaches, fleas, ticks, termites, and more. It comes in a wide range of products and forms, including granules for lawns, gel baits, and liquid for spot treatment on pets.

Fipronil has some mild toxicity issues, including slight skin irritation from direct contact. If ingested, this pesticide can cause sweating, nausea, vomiting, headache, stomach pain, dizziness, weakness, and seizures, but they generally clear up without treatment.

There is no evidence that fipronil causes cancer, but animal studies have shown increased seizures and death in rats that underwent long-term exposure to the chemical.


Imidacloprid is an interesting insecticide, as scientists developed it to mimic nicotine’s insect-killing abilities. This pesticide is generally used to control sucking insects, termites, and various soil bugs. It’s available as a liquid, granule, dust, and dissolvable package and is OK to use inside or outside the home.

Acute exposure to imidacloprid may cause skin or eye irritation, dizziness, breathlessness, confusion, or vomiting. It doesn’t absorb through the skin well, but it can penetrate the stomach lining if ingested.

Fortunately, there are no known long-term effects of using imidacloprid, including any risk of cancer.


Malathion has a wide range of insect-killing uses around the home and yard, plus it’s often used in broad mosquito and fruit fly control. Companies also use it in some anti-lice shampoos. It’s often available as a liquid, dust, wettable powder, or emulsion.

Malathion is relatively toxic to humans via skin contact, inhalation, or ingestion. It may cause nervous system problems that can impact breathing. It may also cause nausea or vomiting, muscle tremors, cramps, weakness, a slowed heart rate, headache, abdominal pain, and diarrhea.

There are no unknown long-term effects from malathion, but the EPA found there is “suggestive evidence of carcinogenicity but not sufficient to assess human carcinogenic potential by all routes of exposure.”


Permethrin is a synthetic insecticide that mimics chrysanthemum flower extract. This allows it to kill many insects, including public mosquito control. Permethrin comes in a wide range of forms, including liquids, powders, dusts, aerosol solutions, sprays, treated clothing, and treated pet collars.

Permethrin’s toxicity is relatively low, but it can cause itching and burning on the skin. If ingested, it can cause sore throat, abdominal pain, nausea, and vomiting. Inhalation can cause nose and lung irritation, difficulty breathing, headaches, dizziness, nausea, and vomiting.

This insecticide is not known as a carcinogen, but long-term exposure has shown some cases of increased liver weight and reduced birth weight.


Trichlorfon is a common insecticide found in products used to control grubs and chinch bugs. It’s available to the public with no limitations, despite having some serious toxicity issues.

Acute toxicity can come from ingestion, inhalation, or even absorption through the skin. Inhalation can initially cause a bloody or runny nose, coughing, chest discomfort, difficult or short breath, and wheezing. Eye contact can initially result in pain, bleeding, tears, pupil constriction, and blurred vision.

Other issues from all levels of contact include pallor, nausea, vomiting, diarrhea, abdominal cramps, headache, dizziness, eye pain, blurred vision, constriction or dilation of the eye pupils, tears, salivation, sweating, and confusion.

In severe cases, it can impact the nervous system, which can cause a wide range of issues, including:

  • Incoordination
  • Slurred Speech
  • Loss of reflexes
  • Weakness
  • Fatigue
  • Involuntary muscle contractions
  • Twitching
  • Tremors of the tongue or eyelids
  • Paralysis of the body extremeties and the respiratory muscles
  • Involuntary defecation or urination
  • Psychosis
  • Irregular heartbeats
  • Unconsciousness
  • Convulsions
  • Coma
  • Death

Long-term exposure can result in the same issues as acute exposure, but with more lasting impacts. It can also cause reproductive harm, birth defects, and cell mutation.


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Fungicides are types of pesticides that kill disease-causing fungi. While they can be beneficial in saving your turf or garden, they can also be harmful.

Below is a list of common fungicides known to be toxic in one way or another.


Azoxystrobin is a common active ingredient in many retail fungicides. It combats a wide range of disease-causing fungi, including rice blast, rusts, downy mildew, powdery mildew, late blight, apple scab, and Septoria.

Azoxystrobin is effective and has relatively low toxicity levels that cause slight skin and eye irritation. Tests have shown no long-term effects of azoxystrobin exposure.


Propiconazole is another common active ingredient in a wide range of fungicides available to retail customers. It controls various fungi, including Erysiphe graminis, Leptosphaeria nodorum, Pseudocercosporella herpotrichoides, Puccinia spp., Pyrenophora teres, Rhynchosporium secalis, and Septoria spp.

While effective against fungal diseases, this fungicide causes only mild issues. Its only notable impact is acute skin and eye irritation that’s mild at worst. There is no evidence of it being a carcinogen or causing reproductive issues.


Sulfur has a broad range of uses, but one common use is as a fungicide. It is available in over 200 products available for purchase, so it’s relatively common in the market.

Despite killing fungi on contact, sulfur has only mild toxicity to humans. If it comes into contact with your skin or eyes, you may experience irritation. If you mistakenly ingest sulfur, you may experience a burning sensation of diarrhea.


Ziram is not only an effective fungicide, but it’s also a soil and seed treatment, and used as an accelerator in rubber and adhesive manufacturing.

The acute toxicity of ziram is mild and limited to skin and eye irritation. The long-term effect may be more serious and include reduced fertility, fetal harm, cell mutation, and thyroid cancer. Ziram comes in many forms, but it’s most harmful in its oil form.

Organic Materials

When some people see a label on a pesticide that reads “organic,” they see that as a safer alternative. This is far from the case.

Many of these harmful products have been pulled from the shelves, but some are still available.


Rotenone is a popular insecticide used in a wide range of organic-labeled products. While it is organic and effective, it also has varying levels of toxicity.

In its concentrated form, rotenone is highly toxic and can cause vomiting or death if ingested, though no deaths from rotenone poisoning have been reported. In other diluted forms, rotenone is far less toxic.

Chronic issues from rotenone exposure can include growth retardation, vomiting, reproductive issues, skeletal deformities, liver and kidney damage, and an increased risk of cancer.


Pyrethrins are natural insecticides derived from certain chrysanthemum plants. While they may sound harmless, they are anything but that.

When inhaled, pyrethrins can cause asthmatic breathing, sneezing, nasal stuffiness, headache, nausea, incoordination, tremors, convulsions, facial flushing and swelling, and burning and itching sensations. Ingestion can cause tongue and lip numbness, nausea, and diarrhea in mild cases.

More severe ingestion symptoms include incoordination, tremors, convulsions, paralysis, respiratory failure, and death.

Protective Equipment to Use When Working Handling Harmful Chemicals

Personal protective equipment (PPE) is critical when applying any pesticide, whether it’s an herbicide, insecticide, or fungicide. This PPE will keep the harmful chemicals from contacting your skin and eyes, and keep you from inhaling it.

The product label will instruct you what to wear when applying it. Here are some of the more common PPE to wear when applying pesticides.


Most product labels will advise wearing gloves, but don’t resort to a pair of cotton or leather work gloves. Wrist-length latex gloves are no good either. For full protection, opt for a pair of elbow-length gloves to prevent the chemical from running down your sleeves.

The approved types of gloves include:

  • Latex (dry products only)
  • Nitrile
  • Butyl
  • Neoprene (not for fumigants)
  • Polyethylene
  • PVC


It may be hot outside when applying these chemicals, but you must remain fully covered when dealing with these chemicals. For pesticides with toxicity category II or IV, you can opt for a basic long-sleeve shirt, long pants, shoes, and socks.

When dealing with category II or I chemicals with high toxicity, you must wear a full-length protective suit that covers your wrists and ankles. Wear this suit over the attire you’d wear for low-toxicity chemicals for full protection.

When mixing chemicals or repairing and cleaning a sprayer, always wear an apron. No, not the “Kiss the chef” apron hanging on your grill. We mean a legit chemical-resistant apron. This is especially important with dealing with toxicity category I or II chemicals.


Chemicals can make their way to your skin through your shoes, so you need special boots to prevent this. We suggest using nitrile or butyl boots. If you can’t get these boots or they are too uncomfortable, you can swap them out for chemical-resistant overboots and washable shoes.

Face, Head, and Neck Coverings

Most pesticides have at least some eye-irritation issues, so you want to keep your peepers safe by wearing a face shield or goggles. Make sure the headband is made of rubber. If it has an absorbent headband, it may absorb the chemical and hold it against your skin.

A wide-brimmed, chemical-resistant hat is also a great idea, especially when spraying uphill. If you can find a protective suit with a hood, that will provide even more protection.


A respirator is a must for many pesticides to avoid throat and lung issues. The pesticide’s label will tell you if you need one and what type to use. There are two main types of respirators: an air-purifying respirator or an air-supplying respirator. Most retail pesticides will require the air-purifying variety.

With the most common toxic active ingredients in pesticides nailed down and how to keep yourself protected, you’re now ready to tackle those weeds, bugs, and fungi without putting yourself in harm’s way.