SCRD A CITIZEN’S GUIDE TO 

DRYCLEANER CLEANUP

 www.drycleancoalition.org

CT

Background

Drycleaners are found in suburbs, business districts, 

and strip malls. Drycleaners use cleaning fluids called 

solvents to clean clothes and other fabrics. Solvents 

can be used safely if properly managed; however, 

solvents can harm people, animals, and plants if 

released to the environment.

Drycleaning solvents can be stored in drums or in 

tanks above or below ground. Spills or discharges of 

these liquids can contaminate soil and water. Cleaning 

solvents or waste containing solvents should not 

be poured on the ground or down the drain. These 

chemicals can seep into the ground from septic tank 

systems or leaking sewer pipes. Even small, unintended, 

or unknown releases from the operation of drycleaners 

can contaminate the environment.

Drycleaners have used many types of cleaning fluids 

through the years. Products based on petroleum, such 

as Stoddard solvent (somewhat like paint thinner), were 

the cleaning fluids of choice in the 1940s and ‘50s. Some 

cleaners still use them. These products are lighter than 

water. If they are released to the ground in quantity, they 

can drain through the soil to float atop the groundwater 

table. Once there, they slowly dissolve into the water 

to form a toxic plume. The plume can affect drinking 

water supplies. Also, vapors from the released solvent 

and plume can rise through the soil into buildings. This 

process is called “vapor intrusion.” 

Other cleaning fluids used by most drycleaners are 

chlorinated solvents. Different types have been used 

in the United States, and some are still used for spot 

cleaning. Perchloroethene (PERC, or PCE) has been 

the solvent of choice since the 1960s. These solvents 

are denser than water, which means they sink instead 

of float. When released to the ground in quantity, they 

contaminate the soil and groundwater for a long time. The 

contamination can last tens to hundreds of years. The 

vapors from these solvents can also intrude into buildings.

Where are the Risks

Drycleaning solvents can threaten human health mainly 

by contaminating indoor air or drinking water. They often 

cannot be smelled or tasted. The amount of solvent found 

in indoor air or drinking water does not have to be large to 

be harmful.

Cleanup Goals

Cleanup goals are chosen to make the site and 

resources safe for their intended use. The cleanup goal 

for groundwater that provides drinking water might differ 

from one for water not used for drinking water. The 

cleanup method(s) must be able to achieve the goal in a 

reasonable time frame.

Time Available for Cleanup

Diverse cleanup methods take different amounts of time 

to reach the cleanup goal. The methods that achieve 

cleanup fastest can cost more in the short term. The time 

allowed for cleanup is balanced against the cost and 

potential reuse of the property. 
Legal Issues

Almost all cleanups will require permits or some regulatory 

program oversight for site activities. Some permits will be fairly 

easy to get. Others, such as permits to inject chemicals to 

clean up the ground or groundwater, can be more difficult 

to obtain. State laws govern the approach used for setting 

cleanup goals. Cleanup goals can vary depending on the risk 

posed and whether the affected property will be or is used 

for housing, commerce, or industry.

What Cleanup Methods are Available

Mitigation Methods

Groundwater

When drycleaning liquids are found in a drinking water 

well, a filter can be installed in the home. The filter will 

remove contaminants until the groundwater is cleaned up. 

It is important to maintain filters by keeping them clean 

and changing them frequently. In some cases, bottled 

water is supplied until drinking water supply lines can be 

installed. These methods provide protection quickly but do 

not fix the problem. Where feasible, affected homes can 

be connected to public water lines to eliminate exposure 

to contaminated groundwater.

Soil Vapor Intrusion

Harmful vapors from solvents in soil or a toxic plume can 

rise to the surface. The vapors can enter into buildings 

through cracks in flooring or concrete slab foundation. 

Several methods are available to slow or stop chemicals 

from entering a building. The methods can be used alone 

or together. The first step is to seal cracks in the floors and 

walls. Gaps around utility conduits, sumps, and elevator 

shafts should also be sealed. If the building has a crawl 

space or the slab has been temporarily removed, plastic 

sheeting placed on the ground is a barrier to soil gas. 

Fan Venting Soil Gas from Under Building to Outside Air

What Affects Cleanup Method Choice

Cleanup can be approached in different ways. 

Direct and present threats to the public, like 

contaminated well water, can be mitigated by 

providing clean drinking water. Mitigation measures 

do not address the source of the problem. A 

remedy, on the other hand, takes steps to clean up 

the contamination.

Many factors go into choosing a cleanup method.

► The type and amount of contamination: Was the 

spill pure solvent or was it mostly water? The 

larger the release, the greater the area that will 

need cleaning. 

► The type of soil at a site: Clay soils are harder 

to clean than sandy soils. 

► How far solvents reach underground: Water 

very far down in the ground is less likely to 

be affected by a release. However, some 

solvents are heavier than water, so they tend 

to sink when leaked into groundwater. It is 

hard to clean up solvents that settle deep 

into groundwater. Some cleanup methods 

become too costly to use.

► Limits on how a cleanup method can be used: 

Digging up the affected area is limited by how 

deep the equipment can reach. Some methods 

work slowly. Some work quickly. Some work 

well in one type of soil but not in another. No 

one method can work for every site.

► Size of work area: The space available to set up 

and use equipment may be too small for some 

cleanup methods.

► Cost of cleanup: While ensuring that a cleanup 

protects human health and the environment 

is the most important factor when selecting a 

cleanup method, cost may also be considered 

when choosing a remedy. A project manager 

may choose a cleanup method that is less 

expensive than another option if both will result 

in the same level of cleanup.

► When the spill occurred: The length of time 

that has passed since the release occurred 

can affect the preferred cleanup method.

► Urgency of threat to people and the environment: 

In some instances, a contaminated site does 

not pose an immediate threat to people or the 

environment and an active cleanup technology is 

not necessary. In these cases, the project manager 

may recommend frequent monitoring of the site or 

place restrictions on its use. 
Pump and Treat

Pump and treat systems remove contaminated 

groundwater for treatment above ground. These systems 

can slow or stop the spread of the toxic plume. Wells 

with pumps in them can be installed below ground 

and at some distance from the treatment unit. The 

treated water can be handled in different ways. It can 

be pumped into a storm sewer or sanitary sewer, or reinjected into the aquifer.

In-Ground Chemical Oxidation

In some cases, drycleaner solvents can be destroyed 

without pumping them above ground. In situ (in 

place) chemical oxidation involves injecting reactive 

treatment products where they are needed to destroy 

contaminants with a goal of leaving harmless by-products 

after treatment. Harmless by-products remain after 

treatment. The oxidants are very effective against 

dissolved solvents and sometimes solvent residues. 

They are less effective on highly concentrated or pooled 

The most common way to mitigate vapor intrusion 

uses a fan or blower to draw air from the soil beneath 

a building and discharge it to the outside air. This 

system is called sub-slab depressurization. These 

systems can be installed in houses with basements 

or slab-on-grade construction. Holes are drilled 

through the slab into subsurface soil. Pipes are 

placed in them, and the opening around each pipe is 

sealed. The pipes are connected to a venting system. 

A fan pulls soil gas from beneath the slab and vents 

it to the outside.

Remediation Methods

Excavation

Digging up contaminated soil and sending it to a landfill 

is the quickest and most direct way of cleaning up a site. 

The use of this method depends upon how much soil is 

affected, how deep the contamination goes, and whether 

there is enough room for the equipment to get to it. Soil 

that is under buildings or in the groundwater is seldom 

dug up.

Soil Vapor Extraction 

Soil vapor extraction (SVE) is a cleanup technique 

for contaminated soils used at some drycleaner sites. 

A vacuum is applied to the subsurface soil to draw 

out soil gas for treatment above ground. The vapors 

can be cleaned above ground by one of the many 

treatment methods available. SVE is very effective 

in sandy soil. It can be used to draw out solvent 

vapors under or next to a building. SVE minimizes 

the potential for vapor intrusion while the site is being 

cleaned up. There must be enough space for the 

equipment above ground. On the down side, reaching 

cleanup goals can take several years.

SVE Treatment System Chemical Oxidation

Solar Power Pump and Treat
solvents. While adding expense to the cleanup, this 

method can help meet cleanup goals faster. Several 

injection wells may be required, but the delivery system 

is portable and likely on the site for a short time.

Thermal

Heating units can be placed below ground to destroy 

or vaporize chemicals that are hard to remove by other 

means. Solvents in silt or clay soil typically are hard 

to remove. Some heating technologies (resistive and 

conductive) use electrical energy to heat the source 

soil to temperatures near or above the solvent boiling 

point. These methods use electrodes or heater units. 

The units are placed within the soil area to be cleaned 

up. Another method, steam heating, injects steam into 

the ground to vaporize the solvents. These vapors 

can be captured by SVE and treated above ground. 

Heating can be more expensive than other methods, 

but it works very well. It should be considered when a 

source zone is hard to treat and cleanup time is short. 

Depending on the amount of solvent, the heating units 

might remain on the site for six months or more.

Biodegradation

All drycleaning solvents can be eaten by microbes 

(bacteria) to some extent. The chemical might degrade 

without treatment if conditions in the groundwater 

are favorable. But the underground conditions often 

must be altered to spur microbes to act upon solvents, 

especially chlorinated solvents. Injecting harmless 

fluids, such as whey or molasses, into the treatment 

zone can stimulate native microbes. If certain types of 

microbes are needed to break down solvents, they may 

have to be added. Biodegradation must be monitored to 

For More Information

The State Coalition for Remediation of Drycleaners (SCRD) website contains reports that discuss site cleanup 

methods. The site has over 175 case studies of drycleaner sites that have been assessed and cleaned up, with 

cost data (www.drycleancoalition.org/). A listing of all SCRD state representatives, complete with contact information 

and links to state drycleaner program websites, can be found by visiting http://www.drycleancoalition.org/members.

cfm#contacts.

U.S. EPA has a webpage called “Citizen’s Guides to Cleanup Methods.” The Guides provide more details about the 

different cleanup methods (www.clu-in.org/products/citguide/).

United States Office of Solid Waste and EPA 542-F-11-013

Environmental Protection Emergency Response August 2011

Agency (5203P) www.epa.gov/tio/tsp

make sure that the plume does not migrate or cause a 

vapor intrusion problem.

Natural Attenuation

This method relies on natural conditions in the subsurface 

to degrade, disperse, dilute, take up, transform, or 

otherwise clean up chemicals. It is often used as a 

remedy for low-risk situations or when there are low 

levels of chemicals in groundwater. This process takes 

a longer time than most cleanup methods. Depending 

on the situation, it may be monitored to prove cleanup is 

taking place.

Institutional Controls

Institutional controls are used with other cleanup methods. 

They prevent people from drinking the groundwater or 

coming in contact with the solvents until the other cleanup 

methods have worked. The controls sometimes restrict 

drilling wells or disturbing the soil after action above 

ground at the site has ended.

Florida DEP Injecting Molasses into the Groundwater