Their natural curiosity, coupled with a lack of awareness about toxic hazards, make them more likely to encounter substances harmful to their health. Animals also have faster metabolisms and smaller lungs than we do. Their bodies have to work harder to try and eliminate these toxins. Not only are they processing these chemicals at a faster rate, they are also breathing them in more rapidly.

Most pet owners go to great lengths to care for their pets, but there are unseen health hazards to pets which are commonly overlooked, yet easily avoided. Here is a list of potentially toxic materials which may be affecting the long-term health of your pet.

1. Flea control chemicals

Flea control is a challenge for most pet owners. Surveys show that as many as 50% of American families report using some kind of flea and tick control product on pets, exposing millions of pets (and children) to flea control chemicals on a daily basis.

Flea repellent products labelled as ‘natural’ may still be toxic to your pet. The chemical d’Limonene, derived from citrus peels and found in many natural anti-flea products, can be highly toxic to cats. Flea sprays and dips which contain “all natural Pyrethrin” can be toxic to some pets, and Pyrethroids , synthetic derivatives of pyrethrins, expose your pet to more chemicals.

Flea control formulations which use essential oils can be particularly hazardous to cats. Essential oils are absorbed rapidly into their skin and enter the bloodstream, and because cats do not efficiently metabolize essential oils, exposure can build to toxic levels. And while there may be no initial adverse reaction, the effects of essential oils can be cumulative and manifest themselves at a later date. Other natural ingredients known to cause allergic reactions or have toxic effects in some animals include Tea Tree (Melaleuca alternifolia) oil and Pennyroyal oil.

Pet-safe Alternatives:

• Electric Flea Traps, also called ‘plug-in’ flea traps, are effective for controlling flea populations and are safe for indoor use around pets. These traps are inexpensive and easy to use.
• Diatomaceous Earth is a nontoxic substance which will control flea populations in the home, and will also kill other insect pests such as ants, roaches, sow bugs and most home insect invaders.

For homes with persistent flea control challenges, it is recommended to use electric flea traps to reduce the active flea population, followed by the application of diatomaceous earth to control emerging populations over time.

2. Lawn fertilizers

Lawn fertilizers are often combined with herbicides, commonly referred to as ‘weed n’ feed’. In a 1991 study published in The Journal of the National Cancer Institute, a link was found between the herbicide 2, 4-D and malignant lymphoma in dogs and non-Hodgkin’s lymphoma in people. According to the study, “researchers report that dogs were two times more likely to develop lymphoma if their owners sprayed or sprinkled the 2,4-D herbicide on the lawn four or more times a year. And even with just one application a season, the cancer risk was one-third higher than among dogs whose owners did not use the chemical.”

Even if you do not use chemical-based lawn fertilizers, your neighbors may. Dogs are more vulnerable than humans to lawn care chemicals since dogs run ‘barefoot’, and often roll, sniff and dig in the grass. Some dogs even eat grass occasionally.

Pet-safe Alternatives:

• Corn gluten is a natural, nontoxic alternative to commercial ‘weed ‘n feed’ products. Corn gluten is an organic fertilizer and a pre-emergent weed killer which has become popular for use in residential lawns as well as school fields and golf courses. Exposure to corn gluten is safe for pets.
• Awareness. Know where your pet goes when outside the home, especially in spring and fall when lawn fertilizers are applied. Wipe or wash your dog’s paws after running on lawns which may have been recently treated with fertilizers.

3. Garden herbicides and insecticides

Herbicides, insecticide baits, sprays and granules are often used in gardens without consideration of the effects these chemicals may have on pets. Slug and snail baits containing metaldehyde are toxic, and can be lethal, to dogs if ingested. Metaldehyde toxicity causes rapid onset of neurological symptoms that can be fatal if untreated. Signs of poisoning begin within one to four hours of exposure. Repeated seizures due to metaldehyde poisoning can elevate body temperature, which can lead to complications similar to those observed in pets suffering from heatstroke. Affected pets usually require hospitalization for 24 to 72 hours after metaldehyde ingestion.

Fly bait and garden insecticides often contain methomyl or carbofuran, which can cause seizures and respiratory arrest in dogs and cats. Organophosphate toxicity from garden insecticides may lead to chronic anorexia, muscle weakness and muscle twitching which may last for days or weeks. Some organophosphate insecticides commonly used include coumaphos, cyothioate, diazinon, fampfhur, fention, phosmet, and tetrachlorvinphos. These insecticides inhibit cholinesterases and acetylcholinesterase, essential enzymes which break down acetylcholine, causing seizures and shaking due to continuous nervous transmission to nervous tissue, organs and muscles.

Pet-Safe Alternatives:

• The Flies Be Gone fly trap uses nontoxic sterilized food materials as bait, and is very effective for outdoor fly control.
• Holey Moley nontoxic mole control uses the natural ingredients Castor Oil and Fuller’s Earth to repel moles. These ingredients are safe for pets, children and the environment.
• See our guides to Natural Slug Control and Nontoxic Garden Pest Control for nontoxic solutions to most common outdoor insect pest problems.
• If pesticides are used, always store them in inaccessible areas—and read the manufacturer’s label carefully for proper usage and storage.

4. De-icing salts

De-icing salts used to melt snow and ice pose a hazard to pets. When dogs lick their paws after having walked on surfaces treated with de-icing salts they may become sick. This limited exposure can lead to short-lived sickness such as hypersalivating, nausea and vomiting. Larger ingestions, according to the ASPCA, can lead to an increase in the blood’s electrolyte levels, weakness, lethargy, moderate irritation to the oral and gastrointestinal system, and even tremors. De-icing salts can also cause burns, cracks and skin irritations on dogs’ paw pads.

The most commonly used de-icer is rock salt (sodium chloride). This is also the least expensive de-icing salt. Other ice-melt formulations use potassium chloride, magnesium chloride, calcium carbonate or calcium magnesium acetate. These formulations are less toxic than sodium chloride but they are also more expensive.

Pet-safe Alternatives:

• Waterproof ‘pet boots’ are recommended during winter walks on treated icy surfaces.
• Sand, crushed cinder, or cat litter can provide traction on icy pavement, although they do not melt the ice.
• De-icers containing calcium chloride or potassium chloride are safer for pets but they are more expensive. Calcium chloride de-icer costs about three times as much as sodium chloride de-icer. De-icers marketed as “pet friendly” are preferred for use, however prolonged exposure can still cause irritation to pets.
• Wash off your dog’s paws with a wet towel after walking on de-icing salts.

5. Antifreeze

Most antifreeze formulations in use today contain ethylene glycol as the principal ingredient. The sweet smell of ethylene glycol attracts animals, but it is deadly if ingested even in small amounts. As little as half a teaspoon of spilled antifreeze can kill an average-sized cat, and eight ounces can kill a 75-pound dog. Unless you catch it early, the damage to pets’ kidneys can be irreversible. Spilled or leaked antifreeze also washes into rivers and lakes, harming fish and other wildlife.

Pet owners should be aware of the potential danger of antifreeze, and keep an eye out for any small green puddles in the garage or the pavement where cars are parked. Leaks from engine coolant systems are not common, but small spills may occur when topping up the car’s coolant reservoir.

Pet-safe Alternatives:

• Use “Low Tox” antifreez made of propylene glycol. This is just as effective as ethylene glycol, but it is a little more expensive. The added cost is hidden – the mix ratio for ethylene glycol is 50:50 (antifreeze/water), while the propylene glycol mix is 60/40. But considering how little antifreeze car owners need to buy, the added cost is a small price to pay for safety to pets and the environment.

6. Household cleaners

According to the EPA, 50% of all illness can be traced to indoor pollution, which can be directly related to the use of household cleaners. The National Center for Health Sciences says “… perhaps the most serious exposure is to modern household cleaners, which may contain a number of proven and suspect causes of cancer.” Cleaning products with ingredients such as bleach, ammonia, chlorine, glycol ethers or formaldehyde can put pets at risk for cancer, anemia, liver and kidney damage.

Even when the toxic cleaners are put away and closed, the vapors left behind can continue to harm both us and our pets.

Ammonia, found in oven cleaners and window cleaning formulations, is an irritant to the mucous membranes. Chlorine is a toxic respiratory irritant that can damage pets’ skin, eyes or other membranes. It can be found in all-purpose cleaners, automatic dishwashing detergents, tile scrubs, disinfecting wipes, toilet-bowl cleaners, laundry detergents and mildew removers. Chlorine is heavier than air and lands in low-lying areas where pets live. Because your pets are smaller and breathe faster than adults, they are even more vulnerable than children to toxic exposure.

Laundry Detergent residue left behind on clothes and pet blankets can be harmful to your pet, especially those that chew on their bedding. Toilet bowl cleaners may be ingested by pets who have the habit of drinking from the toilet bowl.

Pet-safe Alternatives:

• Most home cleaning chores can be done without the need for commercial chemically-based home cleaners which may be toxic to pets. For a list of non-toxic home cleaners which you can make yourself, see our page Nontoxic Home Cleaning.
• Nellie’s All-Natural Dishwashing Powder uses biodegradable, nontoxic ingredients to clean dishes safely and effectively.
• Soap Nuts Laundry Liquid replaces chemical-based detergents with the natural cleaning properties of saponin, extracted from the Soapberry tree.
• Nellie’s All-Natural Laundry Nuggets are nontoxic, biodegradable, hypoallergenic and leave no residue on clothing or bedding.

7. Formaldehyde

Formaldehyde is present in many new home furnishings, household cleaners and some construction materials. It is considered toxic if inhaled or absorbed through the skin. According to the EPA, formaldehyde has been shown to cause cancer in animals.

Pets can inhale formaldehyde from new fabrics, wood-veneer furniture, laminated flooring, wood paneling and doors made of particleboard, plywood, and medium density fiberboard. These pressed woods are bonded with resins containing formaldehyde.

Formaldehyde emissions are highest from new pressed wood furniture, drapery and unwashed new fabrics such as upholstery fabrics, and will gradually subside over time. New furnishings which contain formaldehyde should be set outdoors for a few days to “out-gas” before bringing into the home. Rooms which contain new furniture or draperies should be well ventilated. Wash new clothing and bedding before use to remove formaldehyde-containing fabric finishes. Consider buying solid wood or used furniture.

Newer mobile homes and trailers are made using materials which contain formaldehyde, and many illnesses have been reported from occupants. The mobile homes provided by the government for victims of the Katrina hurricane sickened many people due to the off-gassing fumes.

Air purifiers are ineffective at removing gaseous pollutants and should not be used to mitigate formaldehyde off-gassing. Ventilation is the preferred option.

Pet-safe Alternatives:

• Dog houses should be made of solid wood. Plywood and pressed wood products should be avoided, but if they are used they should be painted on both sides.
• New dog cushions and blankets should be washed or left outdoors to off-gas for several days before letting the dog come into contact with them.
• Dogs kept in apartments or small homes during the day should have access to fresh air. Keep a screened window open if possible.

8. Mothballs

Mothballs, when used properly, are effective at killing moths. But used carelessly, they pose a hidden health threat to pets. Inhalation of mothball vapors causes headaches, respiratory distress, eye irritation and many other symptoms. Ingestion causes toxic poisoning leading to liver damage, respiratory failure, seizures, heart arrhythmia, and the possibility of death. The ingestion of just one mothball can produce significant illness. Repeated inhalation of fumes or ingestion of a few mothballs can be fatal to cats and dogs.

Pets can be attracted to the curious smell of mothballs. This leads them to heightened exposures to which the pet owner is unaware. Ongoing exposure to mothball fumes in the home may remain undetected which results in long-term exposure for the pet.

Mothballs are impregnated with either naphthalene or paradichlorobenzene, both toxic substances. They work by releasing toxic vapors which build up within airtight spaces and kill any moths or moth larvae emerging from the clothing or other stored items. Mothballs should only be used in closed, airtight containers where the pesticide fumes are trapped. If mothballs are not kept in sealed containers, the vapors are gradually released into the room. This long term exposure can pose health concerns if the exposure is high enough.

Pet-safe Alternatives:

• Make moth-repelling sachets using small squares of cheesecloth stuffed with juniper shavings (aromatic cedar, pencil cedar) and place them in closets, bureaus and clothes chests.
• Buy non-toxic pheromone-based clothes moth traps.

Domestic pets may have keen senses of smell and hearing which alert them to danger, but they have no defence against the hidden dangers of chemicals in your home. As a pet owner, you will need to identify the presence of these unseen hazards and take preventive measures to ensure your pet’s long term good health.