USEPA Office of Solid Waste and Emergency Response/Office of Resource Conservation and Recovery 

Policy on the Use of ‘‘Test Methods for Evaluating Solid Waste, Physical/Chemical Methods’’ (SW–846)

The United States Environmental Protection Agency’s (EPA) Office of Resource Conservation and 

Recovery (ORCR) provides analytical and sampling methods to assist the regulated and regulatory 

community and others in implementing the Resource Conservation and Recovery Act (RCRA). These 

methods are published in the Test Methods for Evaluating Solid Waste, Physical/Chemical Methods 

(SW–846) and are available on the ORCR Web site 

(www.epa.gov./epawaste/hazard/testmethods/index.htm). With the exception of those particular 

methods which are promulgated in the regulations to implement RCRA (see 40 CFR 260.11), the 

remaining methods are considered guidance, and users may select any scientifically appropriate 

method when conducting analyses to comply with the RCRA regulatory program.

The Methods Innovation Rule (MIR) published on June 14, 2005 (70 FR34538), reemphasized the flexible 

approach in method selection, when appropriate, when testing for compliance, under RCRA. Since the 

publication of this rule, ORCR no longer uses a formal rulemaking process for publication of method 

updates to SW–846. EPA informs the regulated and regulatory community of new methods and updates 

to SW–846 and solicits comments on them through a Notice of Availability published in the Federal 

Register. This approach is consistent with ORCR’s commitment to fully implement the Agency’s 

performance- based measurement system (PBMS) approach to regulation.

A new effort was developed and approved to reinvigorate the goals of PBMS with the versatility of each 

of our program’s needs. It is called the Flexible Approaches to Environmental Measurements—The

Evolution of the Performance Approach which the Science and Technology Policy Council (STPC) 

approved on February 15, 2008. In 2009, ORCR subsequently adopted the new ‘‘Performance Approach’’ 

as defined by the Forum on Environmental Measurements (FEM). The FEM is a standing committee of 

senior EPA Environmental Protection managers established to develop policies to guide the Agency’s 

measurement community in: validating and disseminating methods for sample collection and analysis; 

for ensuring that monitoring studies are scientifically rigorous, statistically sound, and yield 

representative measurements; and for employing a quality systems approach that ensures that the 

data gathered and used by the Agency are of known and documented quality.

After shortening the name of the PBMS effort to the ‘‘Performance Approach,’’ the FEM’s Performance 

Approach Action Team took a look at the issues surrounding the lack of the program’s progress with the 

ultimate conclusion that the ‘‘one size fits all’’ approach does not work for the diversely different 

programs and authorities each of our major program offices (i.e., air, pesticides, waste, and water) has 

in carrying out their work. To avoid the proliferation of terminology, ORCR has adopted the ‘‘Flexible 

Approach’’ which is consistent with ORCR’s approach to environmental management, based on the 

goals and statutes of EPA program offices.

Under the PBMS approach for RCRA, when labs conducted regulatory required monitoring, the 

regulated community had to either employ a scientifically appropriate method published in SW–846 or 

use any other scientifically appropriate method from another reliable source. This is still true under the 

Flexible Approach. However, when choosing a reliable alternative source, the focus should be on 

measurement objectives, rather than on measurement technologies. In all cases, the user must 

demonstrate the method selected generates data that are appropriate for the intended use. Although 

both approaches are applicable for RCRA, ORCR had dropped the term PBMS, and strongly supports 
the use of the new Flexible Approach to be consistent with the Agency’s new guidance that allows 

each program to determine program specific flexibility when addressing waste analysis issues.

ORCR strongly recommends that persons use the latest version of a SW–846 method whenever possible, 

especially in new monitoring situations, since updated versions of the methods EPA publishes generally 

are in the Agency’s view less subject to misinterpretation, yield improved precision and/or bias, or 

provide for the use of newer and, often, more cost- effective technologies. In situations where it may 

not be appropriate to use the latest method in SW–846, earlier versions may be used. These situations 

may include, but are not limited to, those where an earlier version of a method is required for existing 

permits, consent decrees, waste analysis plans or sampling analysis plans. In addition, laboratories, 

especially small laboratories, may find a previous version of a SW–846 method appropriate if it is more 

cost-effective in meeting the project-specific objectives. The Agency is not imposing restrictions on the 

use of earlier versions of non- required methods contained in SW–846 or precluding the use of previous 

guidance. Nonetheless, the adoption of the latest method version is recommended and should be 

accomplished as soon as possible, as appropriate. When methods are employed, it is the responsibility 

of the user to ensure that the method yields data of a quality appropriate for the particular application 

for which it is being used.

EPA views the methods in the SW–846 compendium as tools for the user to employ in developing 

individual standard operating procedures to meet the goals and objectives of specific projects. This 

approach enables the user to optimize and modify methods for effective performance on unique 

projects. The SW–846 methods are for most applications considered as guidance with the exception of 

those methods required by the RCRA regulations (i.e., Method-Defined Parameters (MDPs), see 40 CFR 

260.11).

In situations where the user is not certain whether the selected method or method modification is 

appropriate, EPA recommends regulated entities contact and seek approval as needed from the 

appropriate regulatory agency (e.g., Federal or State/local government) before applying any method on 

a specific project, including situations where the method is used verbatim.

EPA may publish new methods, revise existing methods, or withdraw methods from the SW–846 

compendium whenever it deems it appropriate. For example, methods may be updated in order to 

reflect new advancements in technology, to reflect the addition of new performance data, or to clarify 

areas of the procedure that experience indicates may be misunderstood. Methods may also be revised 

to reflect new EPA policy regarding the use of certain chemicals and reagents. In other cases, methods 

are removed if the technology is no longer available or applicable. ORCR has developed specific 

procedures for releasing updates, revisions, or withdrawing methods, which are designed to minimize 

disruption to regulatory processes. Specific definitions for the terms associated with a method’s status, 

which support the change procedures, have been developed and provided below.

The Agency will only post the most recent version of a final SW–846 method on the ORCR Web page as 

part of the SW–846 methods compendium (www.epa.gov./epawaste/hazard/testmethods/index.htm). 

Prior versions of methods formerly contained in SW–846 and still considered appropriate for use will be 

available through a separate hyperlink in the future. EPA’s objective is to identify and make available on 

the Agency’s SW–846 Web site the latest information regarding the methodologies that generate 

effective data at minimum costs in response to new technological or scientific advancements, while, at 

the same time, making available earlier versions for those situations where such methods may be 
needed or appropriate (e.g., to determine how a particular analysis had been performed, to determine 

how to comply with a specific permit requirement, etc.).

SW–846 Methods Status Definitions

Analytical methods are officially made a part of the SW–846 manual through a rigorous process of 

technical evaluation both within the Agency and through external review. Methods are also revised as 

needed after a formal evaluation process by analytical experts (e.g., SW–846 work and focus groups) 

and an announcement of method availability and request for public comment in the Federal Register as 

a Notice of Availability. During the method development/evaluation process, the methods go through 

various stages of review and revision. The methods are officially included as part of an update to the 

most current edition of SW–846 at the conclusion of this process.

ORCR employs a specific naming convention (i.e., method number and letter suffix) when publishing 

methods. The naming convention is intended to minimize confusion within the user community 

regarding a method’s developmental status. The method number designates the underlying technology 

(e.g., 8000 series methods designate determinative procedures for organic compounds). A revision to a 

method where the underlying technology does not change is indicated by continued use of the same 

method number and letter, but with a new issuance date. If the revision retains the underlying 

technology, but does not affect the precision and/or accuracy of the data, the revision is considered to 

be minor or nonsignificant and the method number and letter is not changed or sequenced.

If, on the other hand, the revision retains the underlying technology, but changes the precision and/or 

accuracy of the data, the change is considered to be significant and is indicated by a subsequent letter 

suffix (e.g., changes from 8270C to 8270D) and a new issuance date. For example, if the quality control 

recommendations are changed in a manner that improves the bias or precision of the method, but does 

not change the underlying technology (e.g., a tightening of the calibration acceptance criteria), the 

method number stays the same, but the letter suffix is sequenced to the next letter. The differences 

between the earlier and later versions of a method are detailed in the method summary section of the 

revised version regardless of the type of change.

Examples of changes that may be considered minor or nonsignificant include, but are not limited to: 

Language added to a method to provide increased clarity or guidance; expansion of lists of acceptable 

instrumentation, applicability of the method to a matrix not previously referenced, adding new 

compounds to the list of applicable compounds, or changes to instrument specifications which do not 

result in an existing acceptable instrument being rendered unacceptable; or formatting and editorial 

changes that are designed to improve readability or correct spelling or grammatical errors.

ORCR has defined a ‘‘significant change’’ as a change that results in improved analytical results (e.g., 

changes that result in reducing analytical bias or improving data precision). Examples of significant 

changes may include, but are not limited to: a change in the operating parameter which reduces 

analytical flexibility; a change in instrumentation specification which minimizes interference and/or 

optimizes instrument performance (if the use of such interference reduction technique or performance 

enhancement is required); a change in calibration guidance which results in more restrictive 

recommendations; a change that institutes tighter QC recommendations; or a change in the reagents 

that are required by the method.
ORCR understands revisions are sometimes necessary to either enhance the performance of the method 

or to allow flexibilities due to the complexity of sample matrices. In situations where the user is not 

certain whether the selected method, method modification or modification to their plan is appropriate, 

EPA recommends the regulated community seek approval from the appropriate regulatory agency (e.g., 

Federal or State/local government, client) before their use of a revised method; amend their plan (e.g., 

Project Plan, Quality Assurance Project Plan (QAPP), Sampling and Analysis Plan (SAP), Standard 

Operating Procedure (SOP)); and properly document the change when reporting analytical results.

The following method status definitions reflect the current method development process and have been 

developed to add clarity for the method users. ORCR uses these definitions and the terms may vary for 

other program offices.

Final Method—A method that has been formally adopted into the most recent version of the SW–846 

compendium. Before a method becomes final, the validated version would have been made available 

for public review and comment in a Notice of Availability (NOA) or a proposed rulemaking, as 

appropriate.

Validated Method—A method that has undergone development and technical review by EPA, but has 

not been formally adopted into the SW–846 method compendium and published through a Federal 

Register Notice. Since this review includes technical work group approval and/or inter-laboratory 

validation, validated methods are included on the Agency Web site for evaluation and use by the public 

and as a means of soliciting comment from the broader scientific community. The public may use a 

validated method prior to its inclusion in the SW–846 compendium, provided that the users 

demonstrate that it generates data that are appropriate for the intended use.

Revised Method—A method included in SW–846 that has been updated to reflect changes that may be 

editorial in nature and do not impact data or performance comparability, that broaden the method to 

introduce new technologies that may increase productivity, but do not change the fundamental 

technology, or that change the quality control requirements to increase bias or precision.

The number of a method that has been revised does not change, but the method may receive a 

subsequent letter suffix. If the revision is a significant one (as defined above) then both the letter suffix 

and the issuance date are updated. If, on the other hand, the revision is editorial in nature, or consists of 

the addition of new performance data, then only the issuance date is changed. Previous versions are not 

precluded from being used provided that the users demonstrate that it generates data that are 

appropriate for the intended use.

Draft Method—A new method that is being evaluated for possible inclusion into SW–846. It represents 

the latest innovative technological advancements in scientific methodology, but has not completed 

technical review by EPA nor been subject to notice and comment in the Federal Register.

Superseded Method—A superseded method is an earlier version of an SW–846 method or other 

guidance that is no longer included in the SW–846 compendium and has been replaced by a newer 

version. Revised versions of Superseded methods should be viewed as the preferred method. Methods 

in this category are removed from the compendium, but remain available on line and are not precluded 

for use where required for existing projects or where an adequate justification for use exists. The term 
‘‘Superseded’’ is documented in the method title as listed on the EPA Web site for prior versions of final 

methods followed by the date it was superseded.

Withdrawn Method—A method or other guidance that EPA strongly recommends not be used, (e.g., 

cyanide and sulfide reactivity guidance withdrawn, June 14, 2005). EPA has determined that such 

procedures or methods, for the use or technical objectives for which they were originally published, are 

technically inadequate and/or no longer meet such use or technical objectives. This does not mean, 

however, that there would be no situations under which the procedures or methods may be 

appropriate. In any situation in which a person may believe that the withdrawn method is appropriate, 

we strongly encourage consultation with applicable regulatory agencies at the state or federal level. The 

prospective user of the method will need to demonstrate the old method is, indeed, appropriate. Any 

use of these methods, without any such consultation and demonstration, will be done at the user’s risk.

The Agency understands that earlier versions of the SW–846 methods that aren’t required may still be in 

use to meet project specific criteria (e.g., permits, sampling plans, Consent Decrees, etc.). Permits and 

other plans formally approved by regulatory authorities that specify the use of particular methods for 

required analysis continue in effect unless they are changed. However, the Agency encourages the 

regulated community to use the latest version of SW–846, when applicable. EPA will continue to update 

the Methods Status Table to inform the public as to the status of methods in SW–846 and the Policy 

Statement will be added to the SW–846 methods compendium when the Update V package is finalized.

[end of policy statement]