Why Are Traditional Weedkillers Dangerous, and What Are Safer Alternatives?

Your weedkiller isn’t just killing weeds – it could also be harmful for animals, plants, and people.  

What Do Weedkillers Do? 

Weedkillers, or herbicides, are used primarily in commercial settings on row-crop farms, or in urban and suburban areas on lawns, parks, golf courses, and more. Herbicides vary in strength and attack plants in different ways. This includes blocking photosynthesis, root growth — or leaf growth — and reducing water retention.

How Do Weedkillers Work? 

There are a few key factors that distinguish types of weedkillers: Emergence, Selectivity, Persistence, and Translocation. 

Emergence

Refers to if the weedkiller works before the plant sprouts or emerges, or if it primarily works on weeds that have already sprouted.  

Selectivity

Refers to the types of plants it will affect. Some are highly selective, and some are more general. Weedkillers that aren’t selective are more likely to kill non-target plants, such as beneficial native species. 

Persistence

This refers to how long the pesticide will work and impacts how often it needs to be reapplied. Highly persistent pesticides can hang around in the environment for months or even years, sometimes building up in the soil and causing ongoing harm to plants, animals and people. 

Translocation

Refers to how the herbicide moves within the plant and whether it kills on contact.   

What Chemicals and Herbicides Are Used in Weedkillers?

Common herbicides include glyphosate, dicamba, paraquat, atrazine, acetochlor, s-metolachlor, diquat dibromide, and 2,4-D. Some herbicides are only allowed in agriculture or for use by licensed professionals, like paraquat and atrazine. You can find others in products at home and garden stores. The popular “Weed & Feed” for lawncare contains 2,4-D, dicamba, and MCPP, for example. In addition to lawns, herbicides are often used extensively on yards, school grounds, parks, golf courses, and other public places. 

What Are the Health Risks Associated With Herbicides?

• Glyphosate – Cancer, endocrine disruption,  kidney and liver damage, developmental toxicity 
• Dicamba – Reproductive toxicity, liver damage, developmental abnormalities, potential endocrine disruption 
• Paraquat – Parkinson’s disease, cancer, kidney and liver damage 
• Atrazine – Endocrine disruption, developmental and reproductive toxicity  
• Acetochlor – Cancer, endocrine disruption, developmental abnormalities, liver damage 
• S-metalochlor – Cancer, developmental toxicity, kidney and liver damage, potential endocrine disruption  
• Diquat dibromide – Kidney and liver damage,  reproductive and developmental toxicity, neurotoxicity 
• 2,4-D – Cancer, endocrine disruption, developmental toxicity, neurotoxicity  

These are just a handful of common herbicides. 

Is Roundup Weedkiller Safe? 

Roundup is a weedkiller manufactured by the chemical company Bayer, which used to be synonymous with glyphosate. Now, while Roundup for agricultural and professional use still contains glyphosate, Bayer reformulated home and garden Roundup products with other herbicides: diquat dibromide, luazifop-P-butyl, triclopyr, and imazapic. These chemicals post as much or more risk to the environment and human health than glyphosate. Diquat is 200 times more chronically toxic than  glyphosate, and diquat and imazapic are banned in the European Union. 

Are Weedkillers Safe for Pets?  

No. Weedkillers can pose health risks for pets. Studies have found that animals exposed to pesticides have pesticides in their urine, illustrating how much can enter their systems. Herbicides can be absorbed through their paws or ingested by pets that consume grass, increasing their exposure.  

Are Weedkillers Safe for Wildlife? 

No. Herbicides can harm wildlife by destroying their forage and habitat. Glyphosate, for example, is a primary driver of monarch population declines due to impacts on milkweed, the monarch’s primary food source, and also threatens the habitat of many endangered species. Herbicides can also leach into groundwater, contaminating both waterways and drinking water.  

Are Weedkillers Safe for People?   

No. The human health impacts associated with exposure to these chemicals vary significantly and include cancer, developmental and birth defects, liver and kidney disease, reproductive harm, and more. Glyphosate specifically is linked to cancer, endocrine disruption, and kidney toxicity.

Children are particularly vulnerable. The timing of chemical exposure can be critically important, especially for chemicals that disrupt our endocrine systems. Fetal development and infancy are periods of particular susceptibility, as this is the time when young bodies are growing rapidly. The health effects of pesticide exposure during these stages can result in lifelong impacts.  

Further, few studies have been conducted on the impacts of cumulative exposure – the way that exposure to a combination of lawn care-related herbicides, pesticides in our food, and pesticides in our air and water impacts our health. This means we don’t have a clear understanding of how our daily exposure to multiple pesticides affects our health. And the labels on many home and garden weedkillers only warn about incidental exposure to the eyes or skin, but not the impacts of long-term exposure.  

Alternatives to Weedkillers

• Buy organic, untreated plants, soil and seeds. Many of the seeds, soil and plants you’ll find at a nursery are pre-treated with pesticides at much higher levels than standard use. These continue to contaminate your soil and plants at home. Buying organic helps avoid this.  
• Keep your lawn longer – Just a few extra inches of growth will help shade out weeds and grow stronger roots.  
• Identify your weeds This will help you figure out what your soil needs to prevent growth without applying harmful chemicals.  
• Weed by hand. This can be a great way to spend some more time outdoors, and a way for other family members and children to get involved. Make sure to remove the whole plant (roots and all) not just the sprouted part. 
• Use organic solutions – If you must use herbicides, use Organic Materials Research Institute (OMRI) certified products, which are less toxic and less persistent. Inject directly into stems or wipe on cut stems rather than spraying  
• Attract beneficial insects – Prioritize planting things that attract beneficial insects or insects that prey on pest insects and plants instead.   
• Use a flame weeder or a mechanical tool – like a weedwhacker on weeds in driveways or gravel areas. 
• Encourage native species. Native species are naturally hardy and compete well with weeds. Choose well-grown insect/disease-resistant plants. 

What can be used instead of the weedkiller Roundup? Are there safer weedkiller alternatives? 

Yes! The best weedkillers are ones without toxic chemicals. Our herbicide chart lists toxic herbicides and safer alternatives. 

• Look for the Organic Materials Review Institute (OMRI) label. You can trust that “OMRI-approved” means that a product is compatible with the National Organic Standards and is a safer alternative. 
• Look for least-toxic products. A least-toxic pesticide is one that has low human and environmental health hazards. This includes botanicals, essential oils and other plant- and naturally-derived components.  
• Horticultural vinegar or acetic acid are also effective at killing certain weeds. This nonselective weedkiller is a less toxic option that you can find at nurseries. However, these must be used with caution as they can cause skin irritation.  
• Try herbicidal soaps. Herbicidal soaps can kill weeds by drying out their leaves. Plus, the essential oils in many soaps can strengthen their weed-killing impacts. 

Are there pet and animal-safe weedkillers? 

Yes. By avoiding products with labels that say: Toxic, Corrosive, Health Hazard, or Hazardous to Aquatic Environment,  and choosing OMRI-certified products, you can keep your pet safer. In addition, look for weedkiller products with natural ingredients such as vinegar, corn gluten meal, clove oil, citric acid soap, acetic acid, or saltwater.