OSAC 2023-N-0010 Standard Practice for The Collection of Primer 

Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and Other 

Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs

1 

OSAC 2023-N-0010 

Standard Practice for 

The Collection of Primer Gunshot 

Residue (pGSR) Particles from 

Clothing, Vehicles, and Other 

Inanimate Objects using Scanning 

Electron Microscopy (SEM) Stubs

Ignitable Liquids, Explosives, and Gunshot Residue Subcommittee 

Chemistry: Trace Materials Scientific Area Committee 

Organization of Scientific Area Committees (OSAC) for Forensic Science 
OSAC 2023-N-0010 Standard Practice for the Collection of Primer 

Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and Other 

Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs 

2 

OSAC Proposed Standard 

OSAC 2023-N-0010 

Standard Practice for 

the Collection of Primer Gunshot 

Residue (pGSR) Particles from 

Clothing, Vehicles, and Other 

Inanimate Objects using Scanning 

Electron Microscopy (SEM) Stubs 

Prepared by 

Ignitable Liquids, Explosives, and Gunshot Residue Subcommittee 

Version: 2.0 

November 2023 

Disclaimer: 

This OSAC Proposed Standard was written by the Organization of Scientific Area Committees 

(OSAC) for Forensic Science following a process that includes an open comment period. This 

Proposed Standard will be submitted to a standard developing organization and is subject to 

change. 

There may be references in an OSAC Proposed Standard to other publications under development 

by OSAC. The information in the Proposed Standard, and underlying concepts and methodologies, 

may be used by the forensic-science community before the completion of such companion 

publications. 

Any identification of commercial equipment, instruments, or materials in the Proposed Standard 

is not a recommendation or endorsement by the U.S. Government and does not imply that the 

equipment, instruments, or materials are necessarily the best available for the purpose. 
OSAC 2023-N-0010 Standard Practice for the Collection of Primer 

Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and Other 

Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs 

3 

Table of Contents 

1 Scope ....................................................................................................................................... 4

2 Referenced Documents ............................................................................................................ 4

3 Terminology ............................................................................................................................ 5

4 Summary of Practice ............................................................................................................... 5

5 Significance and Use ............................................................................................................... 5

6 Materials & Equipment ........................................................................................................... 6

7 Procedure ................................................................................................................................. 6

8 Environmental Control Samples .............................................................................................. 7

9 Documentation......................................................................................................................... 8

10 Preservation for Re-analysis ................................................................................................ 8

11 References ............................................................................................................................ 8

Appendix A--Example Collection Scheme for Clothing and Vehicles ........................................ 10

Keywords: collection, gunshot residue, pGSR, SEM stub

 
OSAC 2023-N-0010 Standard Practice for the Collection of Primer 

Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and Other 

Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs 

4 

Standard Practice for 

the Collection of Primer Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and 

Other Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs 

1 Scope 

1.1 This practice describes procedures for collecting samples using adhesive lifts from 

clothing, vehicles, and other inanimate objects that could have been exposed to primer gunshot 

residue (pGSR). This practice does not apply to the collection of pGSR from the hands or other 

body parts of a person. 

1.2 This practice should be used by personnel who are responsible for collecting samples 

intended to be analyzed for the presence of pGSR. 

1.3 Units - The values stated in SI units are to be regarded as the standard. No other units of 

measurement are included in this standard. 

1.4 This standard does not purport to address all of the safety concerns, if any, associated 

with its use. It is the responsibility of the user of this standard to establish appropriate safety, 

health and environmental practices and determine the applicability of regulatory requirements 

prior to use. 

2 Referenced Documents 

2.1 ASTM Standards: 

E1732 Standard Terminology Relating to Forensic Science. 

E1188 Standard Practice for Collection and Preservation of Information and Physical Items by a 

Technical Investigator. 

E1459 Standard Guide for Physical Evidence Labeling and Related Documentation. 
OSAC 2023-N-0010 Standard Practice for the Collection of Primer 

Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and Other 

Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs 

5 

E1492 Standard Practice for Receiving, Documenting, Storing, and Retrieving Evidence in a 

Forensic Science Laboratory. 

E1588 Standard Practice for Gunshot Residue Analysis by Scanning Electron Microscopy/ Energy 

Dispersive X-ray Spectrometry. 

3 Terminology 

3.1 Refer to ASTM E1732 and E1588 for terms relative to this document. 

4 Summary of Practice 

4.1 pGSR can be deposited on objects as a result of being near the discharge of a firearm or 

as a result of making physical contact with another surface with pGSR on it. 

4.2 SEM stubs are used for collecting pGSR from clothing, vehicles, and other inanimate 

objects. (1-7) 

4.3 Contamination minimization procedures are applied in order to prevent loss and 

contamination of pGSR. (6) 

5 Significance and Use

5.1 pGSR originates from the explosion of the priming mixture following ignition during the 

firearm discharge process. After a firearm has been discharged, residue can be found on exposed 

surfaces in the vicinity of the fired weapon. (4, 5) 

5.2 The most common reason that pGSR examination is performed is to determine if an 

inanimate object was exposed to firearm discharge. Recovered pGSR can also provide 

information about the constituents of the priming mixture. (4, 5) 

5.3 This practice is applicable to the recovery of pGSR from objects in a forensic laboratory 

or in the field. 
OSAC 2023-N-0010 Standard Practice for the Collection of Primer 

Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and Other 

Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs 

6 

5.4 This practice provides recommendations to be followed in the collection of pGSR 

samples intended for forensic analysis. 

5.5 This practice is intended to be used in conjunction with E1588, E1188, E1459, and E1492. 

6 Materials & Equipment 

6.1 Single-use SEM stubs with affixed adhesive tape, individually enclosed in a protective 

plastic tube container which holds the stub by the pin and protects the surface of the tape from 

contamination. Double-sided carbon adhesive tape is recommended. (1) 

6.2 Clean outerwear (e.g. coveralls or laboratory coat). This can be either a single-use garment 

or a freshly laundered one. 

6.3 Single-use powder-free gloves: nitrile, latex or similar. 

6.4 Large format paper, paper roll or other workspace cover. 

6.5 Single-use scalpel or blade for opening exhibit packages and removing the protective film 

from the adhesive lift, if present. 

6.6 Laboratory wipes, non-woven, lint-free, or similar. 

7 Procedure 

7.1 Establish a collection plan based on consultation with other potential examiners. 

7.1.1 Collection of pGSR shall typically precede collection of other evidence from the same 

area, unless more probative evidence is likely and requires prioritized collection. Objects to be 

sampled for pGSR can be divided into sub-areas for independent sampling. 

7.1.2 pGSR is easily lost from hard smooth surfaces such as painted vehicle panels, metal 

fittings and glass. Samples from these types of surfaces and from surfaces that could be 

disturbed during evidence processing shall be collected before samples from other surfaces, 

unless more probative evidence is likely and requires prioritized collection. 
OSAC 2023-N-0010 Standard Practice for the Collection of Primer 

Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and Other 

Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs 

7 

7.2 Minimize risk of transfer of pGSR and other forms of trace evidence (6) 

7.2.1 Change outerwear between exhibits from different individuals. If the outerwear contacts 

the exhibit or the exhibit’s container, change the outerwear prior to processing the next exhibit. 

7.2.2 Change gloves between each exhibit. 

7.2.3 For exhibits small enough to examine on a workbench, clean the work surface prior to 

laying out each exhibit. 

7.2.3.1 The exhibit can be placed on top of clean paper in order to collect and preserve other 

potential evidence. 

7.2.3.2 Wipe down the packaging before removing the exhibit or remove the exhibit from the 

packaging in a location away from the work surface and in a manner where the exhibit does not 

come into contact with the outside of the package. Change gloves between touching the outside 

of the package and removing the exhibit from the package. 

7.2.4 Store SEM stubs in their protective plastic tube containers. 

7.3 Document the exhibits in accordance with Practice E1492. 

7.4 Determine the area(s) from which to collect (refer to Appendix A). 

7.5 Label each SEM stub container with a unique identifier. 

7.6 Collect from each designated area using an SEM stub until tackiness is lost. 

8 Environmental Control Samples 

8.1 Collect environmental controls as a means of monitoring potential pGSR contamination 

in the collection process through one or more of the following: 

8.1.1 Exposing a collection stub to the room environment for either an established interval or 

prior to each collection from an object. 
OSAC 2023-N-0010 Standard Practice for the Collection of Primer 

Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and Other 

Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs 

8 

8.1.2 Collect directly from workspaces at an established interval or prior to each collection 

from an object. 

8.1.3 Collect directly from the personal protective equipment (PPE) of the collection personnel, 

prior to each collection from an object. 

9 Documentation 

9.1 Record the following details, at minimum: 

9.1.1 Description of the purpose of the examination and description of the sampling procedure, 

including any deviation from a typical collection plan and the reason for the deviation. 

9.1.2 Details of any other relevant observations made during the examination; e.g., stains, 

cuts/tears, etc. 

9.1.3 Description of the pGSR samples collected and their unique identifier. 

9.1.4 Chain-of-custody pertaining to the pGSR samples. 

10 Preservation for Re-analysis 

10.1 Since pGSR analysis via SEM/EDS is non-destructive, the samples will last indefinitely 

as long as the stubs are secured in their protective plastic tube containers. The plastic tube 

containers shall be labeled and either individually sealed, or sealed in a labeled package. 

11 References 

[1] J.S. Wallace and R.H. Keeley, "A Method For Preparing Firearms Discharge Residue Samples 

For Scanning Electron Microscopy", Scanning Electron Microscopy, Vol. 11, 1979, pp 179-184. 

[2] A. Zeichner and N. Levin, "Collection Efficiency Of Gunshot Residue [GSR] Particles From 

Hair And Hands Using Double-Side Adhesive Tape", Journal Of Forensic Sciences, Vol. 38, 1993, 

pp 571-584. 
OSAC 2023-N-0010 Standard Practice for the Collection of Primer 

Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and Other 

Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs 

9 

[3] D. DeGaetano and J.A. Siegel, “A Comparison of Three Techniques Developed for Sampling 

and Analysis of Gunshot Residue by Scanning Electron Microscopy/Energy-Dispersive X-ray 

Analysis (SEM-EDX)” Journal of Forensic Sciences, Vol. 37(1), 1992, pp. 281 -300. 

[4] A.J. Schwoeble, and D. Exline, “Current Methods in Forensic Gunshot Residue Analysis” CRC 

Press, 2000, pp. 5-7, 18-19. 

[5] J.S. Wallace, “Chemical Analysis of Firearms, Ammunition, and Gunshot Residue”, CRC 

Press, 2008, pp. 234-235, 249-251, 268. 

[6] C.C. Quinn, “Cartridge Residue Discharge Contamination – the Search for the Source”, 

Science & Justice, 1998, 38(2), pp 81 -84. 

[7] D.K. Shaffer and K. Yi, “A Comparison of Particle Transfer Efficiencies of Two Collection 

Methods for the identification of Gunshot Residue on Fabric Surfaces by Scanning Electron 

Microscopy-Energy Spectrometry (SEM/EDX)”, Scanning, Vol. 21, 1999, pp 99-100. 

[8] C. Torre, S. Gino, “Epidermal Cells on Stubs Used for Detection of GSR with SEM/EDX: 

Analysis of DNA Polymorphisms”, Journal of Forensic Sciences, Vol. 41, 1996, pp. 658-659 

[9] D. Hall and M. Fairley, “A single approach to the recovery of DNA and firearm discharge 

residue evidence”, Science & Justice, Vol. 44 (1), 2004, pp 15-19. 

 
OSAC 2023-N-0010 Standard Practice for the Collection of Primer 

Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and Other 

Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs 

10 

Appendix A--Example Collection Scheme for Clothing and Vehicles 

A1 Collections from clothing. 

A1.1 Areas of a garment that may have been in close proximity to the discharge of a firearm or 

may have come in contact with a firearm while being worn are recommended for collection. The 

number of SEM stubs collected will be dependent on several factors including, but not limited to, 

size of the object and tackiness of the SEM stub. More areas can be sampled as the case 

circumstances dictate. If a garment can easily be worn inside out, samples from exterior areas and 

additional samples from interior areas can be taken. 

A1.2 Common sample areas of long-sleeve shirts, jackets, sweatshirts, hoodies, etc. include: 

A1.2.1 Right sleeve from the cuff to the elbow 

A1.2.2 Left sleeve from the cuff to the elbow 

A1.2.3 Chest 

A1.2.4 Back 

A1.2.5 Inside shirttail 

A1.2.6 Each pocket (if present) 

A1.2.7 Hood (if present) 

A1.3 Common sample areas of a short-sleeve shirt include: 

A1.3.1 Chest 

A1.3.2 Back 

A1.3.3 Inside shirttail 

A1.3.4 Each pocket (if present) 

A1.4 Common sample areas of pants and shorts include: 
OSAC 2023-N-0010 Standard Practice for the Collection of Primer 

Gunshot Residue (pGSR) Particles from Clothing, Vehicles, and Other 

Inanimate Objects using Scanning Electron Microscopy (SEM) Stubs 

11 

A1.4.1 Front from the waist to the knees 

A1.4.2 Back from the waist to the knees 

A1.4.3 Inside the waistband 

A.1.4.4 Each pocket (if present) 

A1.4.5 Belts present through the belt loops 

A.2 Collection from surfaces of a vehicle. 

A2.1 Areas of a vehicle that may have been in close proximity to the discharge of a firearm or may 

be recipients of secondary transfer of pGSR particles. The number of SEM stubs collected will be 

dependent on the tackiness of the SEM stub. Exterior surfaces and visibly soiled interior surfaces 

of a vehicle are not recommended for sampling because these surfaces tend to be heavily populated 

with non-pGSR particulate. The areas sampled are dictated by the case circumstances. 

A2.1.1 Common sample surfaces include: 

A2.1.2 Windowsills 

A2.1.3 Headliners 

A2.1.4 Front and rear dash 

A2.1.5 Center console 

A2.1.6 Door handles 

A2.1.7 Steering wheel 

A2.1.8 Seatbelts (latches and buckles) 

A2.1.9 Gear shift 

A2.1.10 Seats (headrest, armrest, cushion, and seat back)