Table of Contents
Organic Solvent Cleaning: Regulatory Requirements
The Clean Air Act regulates the emission of
compounds (VOCs) (40 CFR Part 60) and hazardous
air pollutants (HAPs) (40 CFR Part 61 and
40 CFR Part 63), and provides specific standards
of performance to control emissions from solvent cleaning operations (40
CFR Part 63, Subparts T & GG). Evaporation of the organic
solvents from tanks and spray systems may produce sufficient VOC and HAP
emissions to subject an operator to major
source requirements and Title
V permitting requirements.
Controlling VOC emissions can be accomplished in several ways. Evaporation can be minimized by covering tanks, keeping a larger space
above solvent solutions and tank openings, or providing a barrier layer
of water or cold air above the organic solvent solution. Otherwise,
air pollution control
equipment is required on exhaust systems to recover or destroy the
VOCs and HAPs before they are released from the facility.
As part of the Clean Water Act, Effluent
Guidelines and Standards for Metal Finishing (40 CFR Part 433) have
been established that limit concentrations of heavy
metals, toxic organics, and
in wastewater streams. Several components of organic solvent cleaning
operations are classified as water pollutants, including the solvent cleaners
and residual grease, oils and dirt. These materials can enter the
wastewater through liquid dripping off of parts, when cleaning equipment
and changing solution, and from accidental spills or leaks in equipment. Actual limits for effluent constituents depend on the size of the operation
and the amount of wastewater generated from the facility. If the facility
discharges directly to receiving
waters, these limits will be established through the facility's National
Pollutant Discharge Elimination System (NPDES) permit (40
CFR Part 122). Facilities which are indirect dischargers releasing
to a POTW
must meet limits in the POTW's discharge agreement. Wastewater streams
with concentrations exceeding permit limits will require pretreatment
prior to discharge to receiving waters
or to a publicly
owned treatment works. Pretreatment may include separation of
liquid wastes to remove solvents, and settling or precipitation of solid
Solid and Hazardous Waste
Under the Resource Conservation and Recovery
Act (RCRA), organic finishing facilities are required to manage listed
and characteristic hazardous wastes (40 CFR Part
261). Used organic solvent cleaning solutions may contain constituents
listed or characterized as hazardous wastes. Hazardous waste management
(40 CFR Part 262) includes obtaining permits
for the facility in order to generate wastes, meeting accumulation limits
for waste storage areas, and manifesting waste containers for off-site
disposal. Responsibilities will vary according to the amount of hazardous
waste material generated; facilities generating at least 100 kilograms
of hazardous waste per month must comply with the hazardous waste generator
40 CFR Part 262.
Each state and/or region is primarily responsible for the regulation
of non-hazardous solid wastes (those not governed by the hazardous waste
provisions of RCRA). Check with state environmental agencies for
specific information or guidance.
The Emergency Planning and Community Right-to-Know
Act (EPCRA) requires facilities to notify employees, customers and
the surrounding community of certain hazardous chemicals and materials
(40 CFR Parts 355 and 370)
that are present on-site. Large organic solvent cleaning operations
may use hazardous materials in sufficient quantities to subject a facility
to several EPCRA requirements. Facilities may be required to inform
emergency planning committee (LEPC) and the state
emergency response commission (SERC) of the materials stored and used
on-site, devise emergency response plans for reacting to spills, and notify
authorities of accidental spills and releases (40
CFR Parts 302 and 355). The materials
used in organic solvent cleaning solutions may also require facilities
to submit Material
Safety Data Sheets (MSDS) for these materials to state, regional, and
local organizations, while disposed volumes of the material may have to
be documented on annual Toxic
Release Inventory reports (40 CFR Part 372).
Health and Safety
While not directly regulated by EPA, several conditions exist that should
be considered when using organic solvent cleaning solutions. Workers
should be aware of their responsibilities when handling cleaning solutions
during equipment preparation and cleaning activities. Workers should
also know the risks associated with inhaling the VOC emissions from the
Are air emissions from organic solvent cleaning processes properly controlled
and in compliance?
Do organic solvent cleaning solutions come in contact with water streams? If so, do concentrations of pollutants exceed limits established by the
facility NPDES permit or POTW discharge agreement?
- Are all organic solvent cleaning solutions and wastes labeled and packaged
in accordance with 40 CFR Part 262, Subpart C?
Are wastes contaminated with organic solvents classified as hazardous? If so, are the wastes handled and manifested in accordance with 40
CFR Part 262, Subpart B? Are the hazardous wastes segregated
from non-hazardous wastes?
- Has the facility participated in local, regional, or state emergency response
planning activities? Have facility response plans been developed and coordinated
with local authorities?
Organic Solvent Cleaning: Common Causes of Violation
Emission of volatile organic compounds from organic solvent cleaning solutions
may occur and exceed limits established in Title V permits. In addition,
hazardous air pollutant (HAPs) emissions from organic solvent cleaning
operations may violate the standards established in 40
CFR Part 63, Subpart T. The emissions can be captured and treated
to prevent their release to the atmosphere. Common air pollution
control tactics include solvent recovery, solvent incineration, or solvent
concentration. Failure to meet other requirements of Subpart T, such
as monitoring, recordkeeping, and reporting requirements, may also lead
to a violation.
Organic solvent cleaning solutions are liquid materials that can contaminate
water streams. This may occur accidentally, as with spilt material
entering a storm sewer. Contaminated water streams may contain pollutants,
including the solvents, residual sludges, and oils in concentrations that
exceed the limits established by facility NPDES permits or POTW discharge
agreements. As a result, effluent may not be directly released to
water systems or to publicly owned treatment works without pretreatment.
Used organic solvent cleaning solutions containing oils, grease, and other
contaminants that may be classified as hazardous waste according to RCRA. These materials must be labeled, stored, and disposed of in accordance
with 40 CFR Part 262.
Organic solvent cleaning solutions may contain chemicals defined as hazardous
or extremely hazardous substances. Depending on the quantity of material
on-site, facilities must have an MSDS for each solution, maintain records
for TRI reporting, and cooperate with local emergency planning committees.
Organic Solvent Cleaning: Sources of Pollution
Organic solvent cleaning solutions contain materials classified as volatile
organic compounds, hazardous air pollutants, and/or ozone depleting substances.
Organic solvent cleaning solutions may spill due to improper handling or
leaks in tanks, pipes, hoses, or other containers. The liquid material
may enter storm sewers if not properly contained.
In addition to solvents, used organic solvent cleaning solutions may contain
grease, oils, and heavy metals which would classify the material as hazardous
Organic Solvent Cleaning: Pollution Prevention Alternatives
Organic solvent cleaning may be considered a pollution prevention alternative
since it aids in the proper application of coating materials reducing rework
or reject parts. However, other concerns make it less acceptable
than other cleaning methods.
Substitute aqueous cleaners, semi-aqueous cleaners or organic solvents
with lower vapor pressures for organic solvent cleaning solutions. Compared to traditional organic solvent cleaning solutions, aqueous cleaning
solutions and low vapor pressure solvents release fewer volatile organic
Restrict traffic in storage areas to reduce spills and accidents. Keep storage and work areas clean so that spills and leaks are more noticeable
and reaction time is reduced.
Optimize organic solvent cleaning systems to clean adequately with minimum
solvents. Proper adjustment of operating parameters, such as time,
agitation, solution concentration, and temperature, will improve cleaning
without requiring stronger solvents. Modify part arrangement to ensure
that cleaner reaches all surfaces.
Enclose or cover containers of organic solvent cleaning solutions when
not in use to minimize the release of solvent vapors and lower contamination
from facility dust and dirt. Turning off spray systems and maintaining
a cool barrier zone above solvent tanks can also reduce the evaporation
Use solvent test kits to determine the contamination level of the solvent. Ensure that the solution has reached maximum contamination rather than
disposing of it when it â€œlooksâ€� dirty.
Remove contaminants from organic solvent cleaning solutions to retain cleaning
effectiveness. Separate soils, dirt, oils, and other contaminants
using filtration, gravity separation, or membrane technologies (crossflow
filtration). Reducing heat and stopping agitation will promote separation
of contaminants in batch systems.
Segregate non-hazardous wastewater and other materials from hazardous organic
solvents, and label containers to prevent mixing. Separation of the
materials reduces the amount of hazardous waste that is produced.
Recycle spent solvents with recovery units. Use semi-dirty solvent
materials for other cleaning jobs such as paint spills, application equipment
cleaning, and accessory clean-up, where some contaminants will not matter.
Check organic solvent cleaning equipment regularly for leaks and repair
them. Items to check include tanks, pumps, pipes, hoses, valves,
fittings, and storage containers.
Minimize accumulation of soils, dirt, and oils by practicing good housekeeping. Keep the facility clean and use proper part handling procedures to reduce
part contamination initially.
Perform regular maintenance of machinery to remove excess oil, grease,
and dirt; use gloves when handling parts to reduce oils.
Train employees on the safe handling of materials and wastes and encourage
continuous improvement. Training familiarizes workers with their
responsibilities, which reduces spills and accidents.