Are Pesticides Safe after They Dry?

While non-toxic chemicals are usually the preferred method for pest control, there are times when that is just not going to cut it. For some pests like mosquitos, roaches, and fleas, the peppermint oils and witch hazel just don’t hold these types of pests off for long. For pest management of a higher magnitude, you will need to resort to chemical pesticides with an increased level of toxicity. 

Even within the realm of toxic pesticides, there are variations in potency and residual toxicity levels. Lawn chemicals and pesticide containers can hold poison for weeks or months, whereas direct-contact chemical compounds are usually dry and relatively safe within hours to days. Most pesticide labels will give you safety instructions and information on when you can reenter an area that has been treated. While most say once dry, let’s look more into what that means exactly. 

How Long Does It Take Pesticide to Dry?

Most of the insecticides that are used on residential property will be dry within 2 hrs to one day. Humans passing through that will be safe enough that a person shouldn’t experience harmful effects. But an animal or child that is more prone to touching surfaces and putting things in their mouths will ingest more and possibly become seriously ill.

That is why you want to check the label carefully and make sure the area is dry and clean of residual harmful chemicals. Below are some factors that affect the danger duration of pest control chemicals. 

Rate of Airflow

Ventilation is a very important contributor to the amount of time it takes deadly pesticides to dry. Some pesticides are specified to only be used outdoors because the amount of air indoors is not adequate to disperse the harmful chemicals to a level that is safe for human contact. Other types of pesticides will cause long-term health effects if exposure occurs. Make sure to cover your mouth and nose when spraying for insects around your property. 

Density of Aerosol

To kill a wide variety of pests, insecticides come in quite a few air-density configurations. Foggers for heavy roach and flea infestations produce a very fine mist that will make it through all the rooms in a home. This is able to penetrate into soft furniture and fabric and last for a long time.  Other direct contact sprays may just stick to the area they hit and dry after several hours without affecting the air all around the room. 

Type of Pesticide

DDT and Lindane have been discontinued, but they are both associated with skin and health issues as well as toxicological effects. Newer pesticides are typically plant-based and break down into various hydrocarbons once dissolved. While the negative effects of these indoor insecticides might be less severe direct inhalation or large levels of pesticide residue on the skin could lead to adverse effects. 

Surface Type

The property of hard non-porous surfaces like stainless steel are highly unlikely to absorb any of the pesticide waste, making them good surfaces for sanitary work. Some types of unfished wood and soft fabrics like couches and curtains are more likely to hold onto pesticide substances and stay wet longer. Even spraying and careful application are important to avoid soaking areas that will not dry quickly and could cause pesticide poisoning. 

How Long Are Pesticides Dangerous?

Pesticide Bottle

According to the instructions on pest control chemicals, once the initial unwanted pests are exterminated, the pest control solutions should begin to break down and dry up. If pest controllers are not applied correctly, contact pesticides can pose very long-term dangers and adverse health effects. Based on the type of exposure, how much was absorbed, and the pesticide half-life, you can determine how long a pesticide will remain dangerous. 

Exposure Type

Pesticide products can cause exposure in humans through a few different channels. If care is not taken, unsafe levels of pesticide treatment can be inhaled and cause damage to the lungs and nose. Skin exposure can also lead to absorption through the derma and has various effects on humans. Skin irritation is very common after exposure to indoor insecticides. Contact with food on household surfaces and in pet food and water or pesticides in food containers can lead to accidental ingestion and adverse health effects. 

Exposure Amount

A tiny bit of pesticide on your hand is not going to harm you in the same way a blast to the face would. The effects on people and pets can be less or more severe based on the amount of pesticide they were exposed to. Trace amounts should not cause any problems for pets or children.

At moderate and heavy levels of exposure, sickness and death can occur. Pesticide poisoning is the leading cause of accidental suicide, and heavy amounts in the elderly, children, and pets can lead to death.

Residue Ratings

Knowing how long the pesticide you sprayed will stay in the air, soil, and on surfaces can help you make preparations and safe treatment decisions. Typically low (<16) and medium (16 to 59) residual ratings are common in home and yard use. High-residue pesticides that last over 60 days are only used by professionals and mostly in the agricultural industry. 

Pesticide Use with Pets and Children

While there are very few effective pesticides that are also completely safe for kids and pets, you can do a lot to minimize the risk of insecticide poisoning. Make sure to clear the room by removing toys, food, and water bowls, as well as cups and utensils for the kiddos. A pesticide should never come into contact with something a child or animal will put into their mouth without being thoroughly cleaned first. 

Move all children and pets out of the room and keep them out as long as you can. Make sure to prevent entry for even longer than what the label says to keep everyone as safe as possible. If you will be reapplying the pesticide and need to keep it on hand, make sure it is high up and out of reach. If you have fish in a room, pay extra attention to the instructions, and if unsure, remove the tank while spraying. 

Pesticide TypeInfo for ChildrenInfo for Pets
SprayKeep away until dryKeep away until dry
PowderPlace inside walls where children cannot reachPlace inside walls where pets cannot reach
GranulesKeep out of the area until it has dissolved in water and driedKeep out of the area until it has dissolved in water and dried
Traps and BoxesPlace where no access is possible Place where no access is possible


When using sprays inside, it is important to follow the directions carefully. Using too much can build up toxic levels and cause unintended effects. It is also important to let a room air out and make sure all surfaces are dry and free of pesticide residue. If you will need to spray again, make sure it is not accessible to pets or kids and that it isn’t stored anywhere hot. Accidental ingestion of spray is common in third-world and low-income countries.


Common for treating termites and pests in the walls, powder can be very effective and stop nasty critters. Both pets and children like to crawl around and under furniture, and dust left there could prove toxic. Make sure to blow dust into walls and cracks and to sweep or vacuum any powder left behind. Once the powder has been applied and cleaned up, store it in its original packaging away from food and pets or children. 


This type of pesticide is generally used in lawns and yard treatments. Mosquitos and other lawn pests can be wiped out at the same time the lawn is being fertilized. Granules can be extremely dangerous while laying on plants or the ground, so care must be taken when applying them. After the granular is watered in, allow 2 days to dry before pets or children can play there. Continue to wipe pet paws after using the yard for at least a week to avoid tracking chemicals into the house. 

Traps and Boxes

Pest traps and chemical boxes are meant to offer long-term pest control solutions. These boxes are often tempting for children to explore and have ingredients pets find tasty. Keep these in areas where it is impossible for pets and children to access or not use them. Most pests that can be treated by these boxes can be exterminated in a safer manner that doesn’t risk the safety of others around your yard. 

Steps to Keep Safe When Using Pesticides

PPE Spraying Pesticide

While occasional pesticide use may be unavoidable, we can all work to make it just a little bit safer. By opting for the least toxic options, reading the instructions on the product carefully, and taking precautions, you can avoid insecticide-related accidents. Below are some steps to stay safe while eliminating pests. 

Cover Furniture 

Place plastic or easily washable covers over any furniture or surfaces that you want to keep pesticide free. Kitchen and dining surfaces are possible areas of contamination, so covering them can help tremendously. Sofas and furniture with fabric and cushions may also absorb more of the chemicals and can be covered as well. 

Read Labels

Check the label to see how you should spray the chemicals. Often there is a recommended spray distance to help prevent surfaces from building up too much residue. Other helpful information on the label will be how long before it drys and how to reenter the area later. 

Remove all Pets and Children

Get all living creatures that you don’t want to be exposed to the chemicals out of the room. Children and pets should be removed and accounted for outside of the room as they have the habit of slipping back into places they shouldn’t. Also, remove any food or drink objects that might transmit the poison. 

Turn off Central Air

To keep sprays and other aerosols contained and in the correct room of the house, turn off fans, ventilation systems, and central air. This will prevent the chemicals from moving into other rooms or building up in airways and filters. Make sure to follow ventilation guidelines in regard to windows and doors to prevent poisoning yourself. 

Put on Protective Gear

3M Half Facepiece Reusable Respirator 6200, Gases, Vapors, Dust, Paint, Cleaning, Grinding, Sawing, Sanding, Welding, Adjustable Headstraps, Bayonet Connection, Medium

I like to protect my mouth, nose, skin, and eyes when spraying chemicals. While all of this may not be necessary, I stand by better safe than sorry and protect myself. Having the protection also helps me keep my cool while spraying and allows for more accurate extermination and application.

Apply Correct Amount

Do not over-saturate the room, or you may need to wait even longer to return. Spraying beds and curtains with a lot of chemicals can lead to toxins leeching into the air over time and other unintended consequences. 

Leave Area for Specified Time

Stay out of the room for the duration the label has instructed and only enter when it is safe to do so. Upon reentry, I like to keep on my safety gear and make sure everything has been treated correctly. If there are some areas that need to be resprayed, I try to do this now. 

Open for Ventilation 

Often before a full return to the room, a ventilation period is needed. Going into a treated room and opening windows, and turning on fans can help the pesticide move out quicker. If being in the room still gives you a dizzy feeling, allow even more time to air out before entering again. 

Remove Coverings

Take all the clothes off of the surfaces and wash them immediately. Most of these covers will have some level of pesticide residue on them and will need to be cleaned thoroughly. Carpets and other fixed fabrics can usually be dusted and vacuumed to remove most residue. 

Clean floors and Surfaces

 Pets and children like to spend time on the floor, and although the pesticide is dried to be safe for normal absorption, there are still risks. Any surfaces that may have been sprayed can be wiped down with a simple vinegar solution to break down any remaining residue quickly and safely. Mop hard floors as well to ensure complete safety for your family. 

Store Pesticide Safely

After all of the pests have been killed and the rooms are clean, you can let everything come back in. Bring back the stuff you took out and let pets and children roam free. Make sure to store the pesticide safely where no one else can reach it and where you can get to it if needed. Store it away from heat sources and make sure it isn’t leaking or punctured when stored.