Chemical Storage Guide User Manual
Table of Contents
Introduction....................................................................................................................................................1
Chemical Storage Guide Instructions ..............................................................................................................1
1. Identify Storage Group .................................................................................................................................1
2. Review Storage Location and Guidance .......................................................................................................3
General Storage Guidelines.............................................................................................................................4
Storage Location and Guidance Based on Chemical Storage Groups ...............................................................5
Introduction
This document provides information on how to use the Chemical Storage Guide, general chemical storage
guidelines, and a summary of storage locations and guidance based on a chemical’s Storage Group.
Chemical Storage Guide Instructions
The Chemical Storage Guide assists lab personnel in determining appropriate storage locations for chemicals
based on their characteristics. The guide does not cover storage of hazardous waste, compressed gases, or
Drug Enforcement Administration (DEA) Controlled Substances. Before using the guide, read the General
Storage Guidelines found in this document.
Do the following to use the Chemical Storage Guide.
1. Identify Storage Group
Follow the flowchart to identify the Storage Group and recommended storage locations.
Revision Date: 03/26/2024 Page 1 of 7
Copyright © 2024 The President and Fellows of Harvard College
To request this document in an alternative format contact ehs@harvard.edu
Compare the Globally Harmonized System (GHS) pictograms on the chemical’s label to those on the flowchart
or in the table in this section. * Begin at the top of the flowchart where it says Start (or the first row of the table
in this section) and move down until you find a GHS pictogram that is on the chemical’s label. If the flowchart
returns you to another pictogram, continue to move downward until you reach another pictogram that
appears on the chemical’s label.
Many chemicals have multiple GHS pictograms. It’s important to choose the first pictogram that matches one
on the chemical label (the pictogram closest to the top of the flowchart or table).
GHS GHS Hazard Storage Group Conditions
Pictogram Classification
Explosive Storage Group is Explosive or Unstable (EU).
Flammable 1. If Hazard Statement contains “Catches fire spontaneously” or “In
contact with water releases”, Storage Group is Pyrophorics and
Water Reactives (PW). Otherwise, go to the next Flammable Storage
Group condition.
2. If Hazard Statement contains “Flammable liquid” or “Flammable
aerosol”, Storage Group is Flammable Liquids (FL). Otherwise, go to
the next GHS pictogram.
*
If the product doesn’t have a GHS label, search Sigma Aldrich or go to ChemWatch and review their Gold
Safety Data Sheet (SDS) for the same product. Use Section 2: Hazard Identification of the SDS to complete the
Lab Chemical Storage Guide.
Revision Date: 03/26/2024 Page 2 of 7
Copyright © 2024 The President and Fellows of Harvard College
To request this document in an alternative format contact ehs@harvard.edu
GHS GHS Hazard Storage Group Conditions
Pictogram Classification
Corrosive 1. If the chemical is an inorganic acid, Storage Group is Inorganic Acids
(IA). Otherwise, go to the next Corrosive Storage Group condition.
2. If the chemical is an organic acid, Storage Group is Organic Acids
(OA). Otherwise, go to the next Corrosive Storage Group condition.
3. If the chemical is an inorganic base, Storage Group is Inorganic
Bases (IB). Otherwise, go to the next GHS pictogram.
Oxidizing If Hazard Statement contains “May cause fire or explosion; strong
oxidizer” or “May intensify fire, oxidizer”, Storage Group is Oxidizers
(OX). Otherwise, go to the next GHS pictogram.
Toxic If Hazard Statement contains “Fatal if swallowed”, “Fatal if inhaled”, or
“Fatal in contact with skin”, Storage Group is High Acute Toxicity (AT).
Otherwise, Storage Group is General Storage (GS).
If the chemical’s label doesn’t include any of these pictograms or meet any of these conditions, the Storage
Group is General Storage (GS).
2. Review Storage Location and Guidance
Read any storage location and additional recommendations associated with the Storage Group.
Always review Section 7.2: Conditions for Safe Storage and Section 10: Stability and Reactivity of the
chemical’s SDS to determine any special storage requirements and to verify compatibility.
Revision Date: 03/26/2024 Page 3 of 7
Copyright © 2024 The President and Fellows of Harvard College
To request this document in an alternative format contact ehs@harvard.edu
General Storage Guidelines
The following guidelines apply to storage of all chemicals.
• Separate the chemical Storage Groups from each other. Storage in separate cabinets or locations always
meets this requirement and is preferred where space allows. Separating Storage Groups using secondary
containment bins also meets this requirement, unless specifically prohibited in this guide.
• Store chemicals only in cool, dry areas.
• Do not store chemicals in direct sunlight or near a heat source.
• Store chemicals in well-ventilated areas. Do not store flammable liquids or volatile hazardous chemicals in
cold or warm rooms. Refer to the Cold and Warm Room Safety Guidelines document for more details.
• Avoid storing chemicals on the floor when possible. If unavoidable, then store in a secondary containment
bin.
• Do not store hazardous liquids above eye level. Have an appropriate step stool or ladder available if non-
hazardous liquids or dry chemicals are stored at higher levels.
• Use designated labels for peroxide forming chemicals. Refer to the Laboratory Safety Guideline: Peroxide
Forming Chemicals document for more details.
• Record the date received and the date opened on the label of all time-sensitive chemicals.
• Do not remove original labels from containers. Replace manufacturer labels if they are not legible. Include
appropriate GHS information on the replacement label. Label templates can be found on the Laboratory
Labels and Sticker webpage.
• Return chemicals to designated storage locations when not in use.
• Chemicals should not be stored in fume hoods used to conduct laboratory procedures.
• Carefully reseal opened containers before returning to storage. Replace broken, cracked, or deteriorated
caps. Use Teflon tape and paraffin as indicated to control fugitive emissions of volatile high hazard or
stench chemicals.
Revision Date: 03/26/2024 Page 4 of 7
Copyright © 2024 The President and Fellows of Harvard College
To request this document in an alternative format contact ehs@harvard.edu
• EH&S recommends that secondary containment bins, where employed, are labeled with the Storage
Group name.
• Clearly separate chemical storage from hazardous waste storage.
• Refer to the Recommended Storage Groups for Common Acids and Bases document for help identifying
correct storage classes for common acids and bases.
Storage Location and Guidance Based on Chemical Storage Groups
The table in this section includes storage location information and additional guidance based on a chemical’s
Storage Group.
Use the Chemical Storage Guide flowchart to determine the appropriate Storage Group. Alternately, classify a
chemical by assigning the first Storage Group listed in the table that can describe the chemical.
For example, if a chemical is both a flammable liquid and an organic acid it should be stored in the Flammable
Liquids Storage Group since that group appears first in the table.
Storage Group Storage Location Additional Guidance
Explosive or • Contact EH&S or Department Safety Officer.
Unstable (EU)
Pyrophorics and • Flammable storage • Use only refrigerator or freezer designed for
Water Reactives refrigerator or freezer. flammable materials storage.
(PW) • Inert gas glove box. • Store under inert atmosphere when indicated.
• Dedicated cabinet away • Do not store with flammable liquids in flammable
from other storage groups. storage cabinet.
Revision Date: 03/26/2024 Page 5 of 7
Copyright © 2024 The President and Fellows of Harvard College
To request this document in an alternative format contact ehs@harvard.edu
Storage Group Storage Location Additional Guidance
Flammable • Flammable storage • Use refrigerator or freezer designed for
Liquids (FL) refrigerator or freezer. flammable materials storage.
• Flammable storage cabinet. • Do not store in cold rooms.
• Approved safety cans. • Limited amounts of flammable liquids may be
stored outside cabinets or safety cans.
• Place flammable organic acids in dedicated
secondary containment bin.
• Venting a flammable storage cabinet is not
recommended. Contact EH&S before venting.
Inorganic Acids • Standard refrigerator or • Place hydrofluoric acid in dedicated secondary
(IA) freezer. containment bin.
• Corrosive/acid storage • Place perchloric acid in dedicated secondary
cabinet. containment bin. Do not store perchloric acid in
• Standard wooden cabinet same cabinet with organic chemicals including
organic acids.
• Vent corrosive/acid storage cabinets, if feasible.
• Avoid placing in unvented metal cabinets unless
designed for corrosive storage.
Inorganic Bases • Standard refrigerator or • Use a secondary containment bin to separate
(IB) freezer. from acids if stored in same cabinet.
• Corrosive/acid storage • Vent corrosive/acid storage cabinets, if feasible.
cabinet.
Revision Date: 03/26/2024 Page 6 of 7
Copyright © 2024 The President and Fellows of Harvard College
To request this document in an alternative format contact ehs@harvard.edu
Storage Group Storage Location Additional Guidance
Oxidizers (OX) • Standard refrigerator or • Do not store in flammable storage
freezer. refrigerator/freezer or flammable storage
• Corrosive/acid storage cabinet.
cabinet. • Do not store on bare (uncoated) wood or other
• Standard wooden cabinet. combustible material.
High Acute • Standard refrigerator or • Monitor container condition.
Toxicity (AT) freezer. • Minimize storage in cold or warm rooms.
• Secure cabinet, if required • May be stored with General Storage Group.
for specific chemical.
• Consider a vented cabinet
for liquids with high
volatility.
General Storage • Standard refrigerator or • Separation of organic and inorganic chemicals is
(GS) freezer. recommended.
• Any dedicated cabinet or
shelf storage area away
from other Storage Groups.
Revision Date: 03/26/2024 Page 7 of 7
Copyright © 2024 The President and Fellows of Harvard College
To request this document in an alternative format contact ehs@harvard.edu
