oSIST prEN 17648:2021

E-liquid ingredients

The document is applicable to e-liquids, as well as flavour concentrates supplied directly to the consumer for use in e-liquids, intended for the production of aerosol for consumption by inhalation in electronic cigarettes and similar vapour producing devices. It is applicable to eliquids and concentrates intended for the consumer either with or without nicotine content.  
The standard specifies the minimum safety and technical requirements for the selection and control of ingredients for e-liquids and flavour concentrates, as well as some ingredient-related risk assessment and product information requirements for the finished e-liquid/flavour concentrate, when the products are to be used in electronic cigarette devices operated and maintained in the manner prescribed by the manufacturer.
The document is not applicable to packaging, device or refill container materials.

Inhaltsstoffe von E-Liquids

Ingrédients des e-liquides

Sestavine e-tekočin

General Information

• Status: Not Published
• Public Enquiry End Date: 30-Jun-2021
• ICS: 65.160 - Tobacco, tobacco products and related equipment
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 22-Apr-2021
• Due Date: 09-Sep-2021
• Completion Date: 12-Jul-2021
• Ref Project: prEN 17648 - E-liquid ingredients

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN 17648:2021
01-junij-2021
Sestavine e-tekočin
E-liquid ingredients
Inhaltsstoffe von E-Liquids
Ingrédients des e-liquides
Ta slovenski standard je istoveten z: prEN 17648
ICS:
65.160 Tobak, tobačni izdelki in Tobacco, tobacco products
oprema and related equipment
oSIST prEN 17648:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 17648:2021
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oSIST prEN 17648:2021
DRAFT
EUROPEAN STANDARD
prEN 17648
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2021
ICS 65.160
English Version
E-liquid ingredients
Ingrédients des e-liquides Inhaltsstoffe von E-Liquids

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 437.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations

which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other

language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC

Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17648:2021 E

worldwide for CEN national Members.
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Contents Page

European foreword ............................................................................................................................................ 3

Introduction .......................................................................................................................................................... 4

1 Scope .......................................................................................................................................................... 5

2 Normative references .......................................................................................................................... 5

3 Terms, definitions and abbreviations ........................................................................................... 5

3.1 Terms and definitions ......................................................................................................................... 5

3.2 Abbreviations ......................................................................................................................................... 7

4 Ingredient suppliers’ selection ........................................................................................................ 7

4.1 Disclosure of e-liquid / flavour formulation ............................................................................... 7

4.2 Supply chain requirements ............................................................................................................... 8

4.3 Change notifications ............................................................................................................................ 8

5 Ingredient requirements ................................................................................................................... 8

5.1 Ingredient functions ............................................................................................................................ 8

5.2 Ingredient quality ................................................................................................................................. 9

5.3 Undesirable constituents ................................................................................................................. 10

5.4 Ingredient exclusion criteria .......................................................................................................... 11

5.5 Toxicological risk assessment ........................................................................................................ 13

6 Finished e-liquid requirements ..................................................................................................... 14

6.1 E-liquid integrity ................................................................................................................................. 14

6.2 E-liquid related emission requirements .................................................................................... 15

6.3 E-liquid related product information requirements ............................................................. 15

Annex A (informative) Compounds not to be used as ingredients in e-liquids ......................... 18

Bibliography ....................................................................................................................................................... 19

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European foreword

This document (prEN 17648:2021) has been prepared by Technical Committee CEN/TC 437 “Electronic

cigarettes and e-liquids”, the secretariat of which is held by AFNOR.
This document is currently submitted to the Enquiry.
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Introduction

E-liquid is a term describing liquid either prefilled in vaping products, or available in other forms so that

consumers can fill the reservoirs or soak the wicking material of vaping products. E-liquids may or may

not contain nicotine. In either case, they generally contain glycerol and/or propylene glycol together with

additional flavouring components. E-liquids are intended to be aerosolised for inhalation by the user.

This document establishes the general principles and requirements related to ingredients used in e-

liquids and e-liquid components to ensure an appropriate level of consumer safety.

The content is applicable to producers and distributors in Europe and forms a guide for regulators,

enforcement authorities and commercial operators in the area. It is also applicable to consultancies,

laboratories and testing houses engaged in, or planning to be engaged in, the safety evaluation of e-liquids

and e-liquid components.

The recommendations given in this document are relevant to the vast majority of product types currently

available, as well as to those that will be developed. Not all elements of these recommendations will apply

to every type of product, but the definitions may be used to identify recommendations for specific

products within the product sector.

This document can provide state of the art guidance on ensuring the consumer safety of e-liquid

ingredients; however, in cases where national regulations currently exist, said regulations take

precedence over this document.
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1 Scope

This document specifies requirements related to ingredients used in e-liquids and e-liquid components.

It does not cover packaging, vaping device or refill container materials/ingredients.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

CEN/TR 17236, Electronic cigarettes and e-liquids - Constituents to be measured in the aerosol of vaping

products

prEN 17647:2021, General principles and requirements, for filling and holding e-liquids for vaping

products, including containers and cartridges

prEN 17633:2021, General principles and requirements for testing for quality and nicotine levels of e-liquids

ISO 20714, E-liquid — Determination of nicotine, propylene glycol and glycerol in liquids used in electronic

nicotine delivery devices — Gas chromatographic method
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
base e-liquid
diluents, that form the bulk or entirety of an e-liquid
3.1.2
compound
individual chemical substance, that usually have a unique CAS#
3.1.3
constituent
individual chemical substance within an ingredient
3.1.4
contaminant
unwanted and unintended substance or material
3.1.5
diluent

solvent used in the e-liquid to dilute nicotine and/or flavourings and/or to form the aerosol

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3.1.6
e-liquid

base liquid, which may or may not contain nicotine and/or other ingredients, intended for transformation

into an aerosol by an electronic cigarette
3.1.7
e-liquid component

mixture or ingredient supplied directly to the consumer, intended for use in e-liquids

3.1.8
flavouring
ingredient that imparts smell and/or taste
3.1.9
ingredient
compound or mixture of compounds intentionally included in an e-liquid
EXAMPLE VG, PG, nicotine, flavourings
3.1.10
producer

manufacturer of any e-liquid-containing product, e-liquid component, e-liquid ingredient or related

packaging or accompanying documents (e.g. leaflet), supplied to a consumer, who, by importing and/or

putting his name, trade mark or other distinguishing feature on the product presents himself as the entity

legally responsible for the item within the relevant jurisdiction
3.1.11
refill container
receptacle containing an e-liquid, which can be used to refill a vaping device
Note 1 to entry: Also called refill bottle.
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3.2 Abbreviations
Carc carcinogenic
CAS Chemical Abstracts Service registration number

CoE number number of a material listed in the Council of Europe's reports on chemically-defined

flavouring substances and natural sources of flavourings

CLP Regulation (EC) No. 1272/2008 of the European Parliament and of the Council on

classification, labelling and packaging of substances and mixtures
CMR carcinogenic, mutagenic and/or reprotoxic
ECHA European Chemicals Agency
EP European Pharmacopoeia
FEMA Flavor and Extract Manufacturers Association of the United States
FLAVIS European Union flavouring information system
FL-number FLAVIS number
GRAS Generally recognized as safe
IARC International Agency for Reasearch on Cancer
IOFI International Organization of the Flavor Industry
JECFA Joint FAO/WHO Expert Committee on Food Additives
Lact. Lactation
Muta. Mutagenic
NTP National Toxicology Program
Repr. Reprotoxic
Resp. sens Repiratory sensitizer
TPD Tobacco Products Directive
USP United States Pharmacopeia
4 Ingredient suppliers’ selection
4.1 Disclosure of e-liquid / flavour formulation

The e-liquid producer shall ensure they receive full disclosure of all ingredients used in the final e-liquid

or e-liquid component, including of any flavouring pre-mixes that may be used in the production of an e-

liquid. Disclosure information is pivotal for proper risk assessment (see 5.5) and control over potential

constituents of concern (see 5.3).

The e-liquid disclosure shall consist of the list of individual ingredients, including their use level or

appropriate concentration ranges that are sufficient to inform the risk assessment.

Where the ingredients are individual compounds, there shall be sufficient information to unambiguously

identify the specific chemical entity, including stereochemistry information where applicable (typically

ensured through identification of appropriate CAS and/or FL-number).
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Where ingredients consist of extracts of natural raw materials, disclosure information shall include the

presence and maximum levels of any toxicologically undesirable constituents as identified in 5.3.

Sufficient information to perform the toxicological assessment (see 5.5) typically includes identification

numbers such as CAS, FEMA, JECFA CoE and/or FL-numbers. These numbers generally provide some

information on the plant botanical name, the plant part used, and/or the extraction process used which

allows the main constituents in the composition of the mixture to be characterized through available

literature, where required in the toxicological risk assessment.

Where ingredients consist of mixtures of individual compounds and/or extracts of raw materials, the

disclosure information described above for each of the individual compounds and/or extracts of raw

materials in the mixture, shall be provided. If insufficient compositional information is available from the

identification information provided by the supplier, for the toxicological risk assessment to support the

proposed level of use of the ingredient in the e-liquid, chemical analysis may be used to help identify the

main constituents of the natural extract to further inform the risk assessment.
4.2 Supply chain requirements

All e-liquid ingredients shall be supplied with a unique batch code. The producer’s own unique batch code

for the final e-liquid shall ensure traceability back to these individual ingredient batch codes.

All e-liquid ingredients shall be accompanied by the relevant certificates of analysis and/or certificate of

conformity demonstrating compliance with the purity requirement specified in 5.2.

To ensure sufficient quality in the supply chain, it is recommended to use ingredient suppliers accredited

for food flavour or pharmaceutical ingredient production.
4.3 Change notifications

Producers shall ensure their ingredient supply chain informs them of any changes to the supplied

ingredients that may affect the composition and/or quality of the ingredients. This includes, but is not

restricted to, changes to manufacturing process, changes to geographical origin(s) of the raw ingredients

used to produce natural extracts, changes to recommended storage conditions and shelf life. The

producer shall ensure they have appropriate documentation to demonstrate the modified ingredients

still meet the purity requirements as specified in 5.2. Any such changes shall result in a new unique batch

number, both for the modified ingredient and the final e-liquid.
5 Ingredient requirements
5.1 Ingredient functions

E-liquids are expected to consist of only diluent(s) and optionally flavouring(s) and nicotine. Substances

whose only function is as a preservative or to impart colour to an e-liquid or subsequent aerosol

intentionally, shall not be added to e-liquids.

NOTE E-liquids may end up having a colour due to ingredients that have other functions and may change colour

over time.

Preservatives may be present as constituents from ingredients, but then their final level needs to be taken

into account in the toxicological risk assessment. If there are exceptional reasons why other ingredients

might be required, such as antioxidants or others, their inclusion shall be justified, taking into account

their toxicological profile and all risk-benefit considerations.
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5.2 Ingredient quality

All solvents forming the base e-liquid, as well as the nicotine used in e-liquids shall meet appropriate

pharmaceutical standards.

Only nicotine of recognized pharmaceutical grade shall be used . Supporting documentation shall

include certificate(s) of analysis and/or certificate(s) of conformity. If nicotine salts are used as either an

ingoing ingredient, or formed in situ, the nicotine used to form the nicotine salts shall be of the before

mentioned recognized pharmaceutical grade quality and the acid added shall be equivalent to, or of better

quality than, European or US food grade quality, with supporting documentation including certificate(s)

of analysis and/or certificate(s) of conformity.

Only propylene glycol (2,3-propanediol) of recognized pharmaceutical grade shall be used as a diluent .

Supporting documentation shall include certificate(s) of analysis and/or certificate(s) of conformity.

Where EP propylene glycol is used, an additional requirement is that the level of di-ethylene glycol

contamination shall be controlled to ensure it does not exceed 0,1 %w/w.

Only glycerol (1,2,3-propanetriol) of recognized pharmaceutical grade shall be used as a diluent .

Supporting documentation shall include certificate(s) of analysis and/or certificate(s) of conformity.

Where water is used as diluent, it shall be equivalent to, or of better quality than European or US

pharmaceutical grade quality purified water or water for injection . Supporting documentation shall

include certificate(s) of analysis and/or certificate(s) of conformity.

Only ethanol of recognized pharmaceutical grade shall be used as a diluent . Supporting documentation

shall include certificate(s) of analysis and/or certificate(s) of conformity.

Flavourings are usually supplied in a solvent. The solvent(s) used for these products shall be equivalent

to, or of better quality than, European or US food grade quality, with supporting documentation including

certificate(s) of analysis and/or certificate(s) of conformity.

Except for tobacco extracts, only flavourings, whether natural or artificial, that are also authorized for use

in food shall be used.
Examples of these are the flavouring agents listed on the following lists:
• Annex 1 of European Food Regulation EU 1334/2008
• Substances Added to Food Inventory of the United States
• FEMA GRAS listings

• IOFI Global Reference List of Natural Complex Substances / Natural Flavouring Complexes

NOTE The European Union list of flavouring substances can also be consulted in the form of the Food

Flavourings Database - FLAVIS.

All shall be of equivalent quality, or better than, European or US food grade quality.

For example: nicotine meeting the requirements specified in the European Pharmacopoeia (EP), Nicotine

Monograph, or those specified in the United States Pharmacopeia (USP), Nicotine Monograph.

For example: propylene glycol meeting the requirements specified in the EP Propylene glycol Monograph, or those

specified in the USP, Propylene Glycol Monograph.

For example: glycerol meeting either the EP Glycerol Monograph or the USP, Glycerin Monograph.

For example meeting the requirements of either the Purified Water for Injection Monograph or the Purified Water

Monograph from either the EP or the USP.

For example, meeting the requirements of the EP Ethanol (96 percent) Monograph, Anhydrous Ethanol or the

USP, Ethanol absolute Monograph.
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For tobacco extracts, the following families of compounds that can be concentrated in the extraction

processes, shall be considered in the toxicological risk assessment (5.5) that is required to support the

use of the extract as an ingredient in the final product:

• Tobacco specific nitrosamines (TSNA’s), specifically N-nitrosonornicotine (NNN), nicotine-derived

nitrosamine ketone (NNK), N′-nitrosoanatabine (NAT) and N-nitrosoanabasine (NAB)

• Cyclic aromatic hydrocarbons, such as phenol and methylphenols (o-, m- and p-cresol) and polycyclic

aromatic hydrocarbons, such as benzo[a]pyrene,
• Metals (Nickel, Lead, Cadmium, Chromium, Arsenic, Mercury)
• Pesticides
• Nicotine-relevant alkaloids

Any other potential ingredients added to the final product shall be at least of European food grade purity

or equivalent or higher.
5.3 Undesirable constituents

Certain toxicologically undesirable constituents that can be naturally present in flavourings, are listed in

Table 1. The presence of those undesirable constituents in the final e-liquid shall be kept as low as

possible, through controlling their limited presence in natural flavourings and/or by limiting the

inclusion level of natural flavourings containing undesirable constituents in the e-liquid. Maximum levels

of these undesirable constituents in the final e-liquid shall be limited to the maximum levels listed in

Table 1.
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Table 1 — Maximum levels of certain undesirable constituents in the final e-liquid

Compound CAS number(s) Maximum level in final e-
liquid in mg/kg
Beta-asarone 5273–86–9 1
1-Allyl-4-methoxybenzene, 140–67–0 10
Also known as estragol
Hydrocyanic acid 74–90–8 35
Menthofuran 494–90–6 200
17957–94–7
80183–38–6
4-Allyl-1,2-dimethoxy-benzene, 93–15–2 1
Also known as methyleugenol
Pulegone 89–82–7 20
Quassin 76–78–8 0,5
1-Allyl-3,4-methylene dioxy 94–59–7 1
benzene, also known as safrole
Teucrin A 12798–51–5 2
Thujone (alpha and beta) 76231–76–0 0,5
546–80–5
471–15–8
Coumarin 91–64–5 5

NOTE Attention is drawn to the ingredient exclusion requirements related to ingredient hazard classifications

in 5.4 and that undesirable constituents presenting CMR properties, when present above certain levels, can result

in the classification of the natural flavouring .

Based on the above requirements, maximum levels of these undesirable constituents shall be set in the

ingredient specifications for all flavourings that are known to potentially contain these undesirable

constituents.
5.4 Ingredient exclusion criteria

Ingredients with the hazard classification listed in Table 2 shall not be used in e-liquids.

e.g. presence of methyl eugenol (CAS# 93-15-2, considered as Muta2 H341 and Carc2 H351) should be below 1%

in natural flavourings such as rose oil.
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Table 2 — European Union CMR and respiratory sensitization classifications
Classification
Hazard- Hazard
class
and Code Warning of danger text
categor
Class Category y code
Muta.
Category 1A
May Cause genetic defects < exposure
H340
route >
Germ cell Muta.
Category 1B
mutagenicity 1B
Suspected of causing genetic
Category 2
Muta 2 H341 defects < exposure route >
Category 1A Carc. 1A H350 May cause cancer < exposure route >
Carcinogenicity
Suspected of causing
Category 2
Carc. 2 H351 cancer < exposure route >
May damage fertility or the unborn
Category 1A H360
Repr. 1A child < exposure route >
May damage fertility < exposure
H360F
route >
May damage the unborn
H360D
child < exposure route >
H360F May damage fertility. May damage the
D unborn child < exposure route >
Category 1B Repr. 1B
Reproductive
May damage fertility. Suspected of
Toxicity
H360Fd damaging the unborn child < exposure
route >
May damage the unborn child.
H360Df Suspected of damaging
fertility < exposure route >
Suspected of damaging fertility or the
Category 2 Repr. 2
H361 unborn child
Lactating Lact. H362 May cause harm to breast-fed children
Sensitization of
Respiratory May cause allergy or asthma
the respiratory Resp.
Sensitisers H334 symptoms or breathing difficulties if
tract (or the Sens 1
Category 1 inhaled
skin )

< exposure route > = state route of exposure if it is conclusively proven that no other routes of

exposure cause the hazard.

Skin sensitization is mentioned in brackets because the official CLP hazard class wording combines

respiratory and skin sensitization and they are then distinguished at the hazard category level. For the

purposes of this table, only the respiratory sensitisers, not skin sensitisers (H317) are meant.

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STOT category 1 (lung) classified ingredients should not be used, unless a robust risk assessment of its

use in the final e-liquid, that includes appropriate data and is documented in a Toxicological Risk

Assessment (see 5.5) supports the concentration used.

In addition, ingredients are also considered unsuitable for use if they have been identified as any of the

following:

• classified as “Carcinogenic to humans” (Group 1), “Probably carcinogenic to humans” (Group 2a) or

“Possibly carcinogenic to humans” (Group 2b) by IARC

• identified by the United States National Toxicology Program (NTP) as either “Known” or “Reasonably

Anticipated To Be” human carcinogens

• listed in Part A of Annex III of the European Parliament and the Council. Regulation (EC) No

1334/2008 of the European Parliament and of the Council of 16 December 2008 on flavourings and

certain food ingredients with flavouring properties for use in and on foods, and its updates.

• being psychotropic, other than nicotine

NOTE A list of psychotropic substances under international control has been established by the UN

Commission on Narcotic Drugs, where schedules 1 and 2 list the drugs and substances under international control

(https://www.unodc.org/unodc/en/commissions/CND/conventions.html).

• The only exception to the above is if scientific data has become available after the evaluation by the

relevant scientific expert group that resulted in the inclusion of the compound in the lists mentioned

above, that has demonstrated the mechanism of action for the specified toxic end point is not relevant

to humans. In that case the ingredient can be used but the documented toxicological risk assessment

determining the supportable concentration in e-liquid shall include a scientific justification for its

use despite its presence on one, or more, of the above lists (see 5.5).

• Oils and fats (mineral or vegetable) shall not be used as diluent or in any other way form part of the

base e-liquid.

• Certain compounds should not be used as ingredients in e-liquids. They may however be present as

impurities and as such their levels should be controlled in line with the toxicological risk assessment

for the final e-liquid. A non-exhaustive list is included in the annex.

• Additionally, nicotine shall not be added as an ingredient in e-liquids where the product information

indicates this is a nicotine-free e-liquid.
5.5 Toxicological risk assessment

Use level of each ingredient shall be supported by a toxicological risk assessment to ensure its safe use in

a final e-liquid. A Toxicological Risk Assessment report supporting each commercial e-liquid stock

keeping unit shall be established and available upon request. It shall be revised at least every 5 years to

include critical new data on ingredients hazard or on product use patterns.
NOTE 1 A single TRA can support various stock keeping units.

The toxicological risk assessment shall consider both the potential hazards associated with the ingredient

and its expected exposure to the consumer in order to determine the supportable level of ingredient use.

In addition, potential thermal degradation of the ingredient due to the aerosolization process shall be

considered.
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NOTE 2 Particularly for ingredients used at higher levels, measurement of potential degradation products under

vaping relevant conditions would also be expected to support the risk assessment. The potential for degradation

will depend on the ingredient properties as well as the vaping device in which it is being used. As a practical guide,

for less volatile ingredients, levels above 0,1 % can be considered higher use levels in this context.

Ingredient hazard characterization includes a thorough literature review of publicly available

toxicological data, with special attention on key end points related to inhalation exposure route.

Exposure assessment shall consider the intended concentration of ingredients, their transfer into aerosol

in the aerosolisation process, as well as an estimation of high e-liquid consumption.

The consumption estimate should be established by knowledge of consumer product behaviour,

including at least the 90th percentile of the daily dose distribution curve. In case the ingredient transfer

rate is not measured, a conservative default assumption of 100 % transfer should be used

...