EPA's Safer Choice Criteria for Processing Aids and Additives
A large set of chemicals that play supporting roles in product formulations, Safer Choice
will now group processing aids and additives as a class, with tailored criteria for each
subclass. These chemicals (often considered commodity or generic ingredients) are
diverse in structure and function, but have in common, beyond their formulary
supporting roles, that their chemical characteristics and long-standing safe use make
them a low hazard concern. For example, physical-chemical properties (like simple
acids, when controlled for product pH) or essential functionality in humans (like
polysaccharides) can indicate low hazard. Like colorants, polymers and related
chemicals, processing aids and additives are often data-poor. Yet, they are very
common ingredients in cleaning and other products and frequently provide multiple
functional attributes.
In this document, Safer Choice has sets out parameters and explanations for qualifying
processing aids and additives, organized into eleven subgroups, for use in Safer Choice
products. At a minimum, they must meet the specific criteria for their subgroup and
comply with the baseline requirements in section 5.2 of the Safer Choice Standard.
Inorganic spectator ions
Conditions: Must be an inorganic salt with ions that pose a low concern for human and
environmental health.
Rationale. Salts containing these ions are expected to dissociate in aqueous
environments. Ions like calcium, potassium, magnesium, sodium, and chloride are
essential nutrients for biological processes. Available experimental data suggests there
is no hazard concern for these chemicals.
Qualifying chemicals: sodium chloride, potasssium chloride, magnesium chloride,
magnesium chloride hexahydrate, calcium chloride, and calcium chloride dihydrate.
Simple acids and bases
Conditions: Are not used at concentrations that alter the permitted product pH range—2
to 11.5. Do not demonstrate potential for protein-binding (as with NH4). Must have
acceptable counter ions (see spectator ions).
Rationale. Simple acids and bases provide a pH-adjustment functionality to product
formulations. Potential health effects are associated with their corrosive nature when
used at high concentrations outside Safer Choice's acceptable pH range.
Qualifying chemicals: potassium hydroxide; sodium hydroxide; sulfuric acid; hydrochloric
acid (aqueous); sulfurous acid, monosodium salt (aqueous); and disulfurous acid,
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disodium salt (aqueous).
Silicates
Conditions: Are not used at concentrations that alter the permitted product pH range—2
to 11.5. Must have a molar ratio of Si02 to [M]20 of equal to or greater than 2, where
M is sodium (Na) or potassium (K), and acceptable counter ions (see spectator ions).
Rationale. Potential health effects are associated with the alkalinity from high molar
ratios of sodium or potassium, outside Safer Choice's acceptable pH range. Provide
necessary builder functionalities in products and pose a low concern when the amount
of silicate to counter ion is in the specified range.
Qualifying chemicals: sodium silicate, sodium metasilicate, disodium disilicate, calcium
silicate, sodium metasilicate pentahydrate, sodium metasilicate nonahydrate, and
potassium silicate.
Simple sugars
Conditions: Must be non-derivatized, monosaccharides with the general molecular
formula of [CH20] n, where n is equal to or greater than 3. Or, disaccharides,
oligosaccharides, or mixtures of these comprised of the following sugars: glucose,
fructose, and sucrose, lactose, galactose, mannose, or maltose.
Rationale. Simple sugars are naturally occurring chemicals that are rapidly metabolized
and used as an energy source. Available information suggests there is no hazard
concern for these chemicals.
Qualifying chemicals: glucose, sucrose, molasses, blackstrap, dextrin, and corn syrup.
Polysaccharides
Conditions: Must be comprised of repeating units of one or more of the acceptable
sugars and have a molecular weight great than 1,000 Daltons (i.e., typically not
bioavailable). If the qualifying polysaccharide is bioavailable (e.g., starch), then it must
metabolize to simple sugars.
Rationale. Polysaccharides made up of qualifying simple sugars (low concern) are
themselves of low concern. Available test data confirms a low-concern for these
chemicals (e.g., data set on xanthan gum). Also, polysaccharides with low water
solubility are expected to have limited bioavailability and thus low hazard concern.
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Qualifying chemicals: xanthan gum, guar gum, cellulose, maltodextrin, starch,
carrageenan, and cellulose (regenerated).
Polysaccharide derivatives
Conditions: Sugar components must meet the requirements of the "polysaccharides"
group. Saturated aliphatic (linear or branched) derivates must only contain: hydroxyl
groups; carboxylic acids, esters, or salts (with qualifying counter ions); and ethers.
Further, acceptable derivatives should have a molecular weight greater than 1000 and
no surfactant properties.
Rationale. Polysaccharide derivatives made up of qualifying simple sugars (low
concern) are themselves of low concern. They are neutral or anionic substances with
non-reactive functional groups. Available information suggests there is no hazard
concern for these chemicals.
Qualifying chemicals: carboxymethyl cellulose (sodium salts), hydroxyethylcellulose, 2-
hydroxypropyl methyl ether cellulose, methyl ether cellulose, hydroxybutyl methyl
cellulose, starch (2-hydroxyethyl ether), starch (2-hydroxypropyl ether), cellulose (2-
hydroxypropyl ether),and inulin (carboxymethyl ether, sodium salt).
Mineral ions
Conditions: Group does not include phosphorus-based or other mineral ions implicated
in the nutrient loading and eventual eutrophication of water bodies. Cannot contain non-
qualifying ions (see inorganic spectator ions above).
Rationale: Available data indicates there is no hazard concern for these chemicals;
some class members, like sodium sulfate, have complete data sets that meet the Safer
Choice criteria. They freely dissociate in water to their component moieties and
qualifying counter ions. They are common components in minerals and ubiquitous in
nature.
Qualifying chemicals: sodium carbonate, potassium carbonate, sodium bicarbonate,
potassium bicarbonate, sodium sesquicarbonate, potassium sesquicarbonate, sodium
sulfate, sodium metabisulfate, potassium sulfate, calcium carbonate, magnesium sulfate
and heptahydrate, and sodium thiosulfate.
Non-crystalline clays, silicates and alumino-silicates
Conditions: Limited to minerals containing oxides of silicon, aluminum, calcium, sodium,
potassium, or magnesium. Must be amorphous or rounded in shape and not contain
any crystalline morphology (candidates with crystalline structures that do not contain
needles or fibrous components will be evaluated on a case-by-case basis). Must not be
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nano-sized. If added to a product that is a powder or in dry form, the distribution of
particles below 10 microns (the inhalation threshold) must be less than 1 percent and
below 3.5 microns (the deep-lung respirability threshold) must be at 0 percent, as
demonstrated by a generally accepted method for measuring particle size.
Rationale: Evidence only of potential adverse human health and environmental effects
from crystalline structures (which pose concerns for lung overload and respiratory
effects, like silicosis). Otherwise, available data indicates there is no hazard concern for
these chemicals (and none is anticipated based on current and projected use levels).
Qualifying chemicals: calcined kaolin, kaolin, fuller's earth, silica, silica (amorphous,
fumed, crystalline-free), amorphous silicon dioxide, kieselguhr (calcined), silica gel,
uncalcined diatomaceous earth, bentonite, pumice, smectite clay, perlite (expanded),
nepheline syenite, and zeolite A and zeolite (based on data set; is crystalline, but not
fibrous or needle-like).
Hydroxy carboxylic acids and salts
Conditions: Structures must contain at least one short-chin (C3 to C6) aliphatic
(branched or linear, with one or more hydroxyl groups) carboxylic acid and associated
salts must be from the group of qualified counter ions (see above).
Rationale. Some class members, like citric acid and lactic acid, have complete data
sets that meet the Safer Choice criteria. In general, extensive anecdotal evidence
indicates low hazard concerns for the class. Class members are present in biological
processes, e.g., products of fermentation, sugar derivatives, and reactants or products
in metabolic pathways (like Kreb's cycle anaerobic glycosis).
Qualifying chemicals: gluconic acid, sodium gluconate, sodium citrate, potassium
citrate, citric acid, lactic acid, and sodium lactate.
Alkyl carboxylic acids and salts
Conditions: Scope of class is limited to short-chain, non-functionalized alkyl groups
(eliminates chemicals with mild surfactant properties). Class members must contain at
least one carboxylic acid functional group and a non-functionalized linear alkyl chain,
less than C6 in length; salts must be one of the qualified counter ions (see above).
Rationale: Available data for chemicals in this class indicates low potential for human
health and ecological hazards and low persistence. Extensive anecdotal evidence
indicates low hazard concerns in general.
Qualifying chemicals: acetic acid, propionic acid, calcium propionate, sodium
proprionate, sodium acetate, potassium acetate, calcium magnesium acetate, and
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sodium formate.
Triglycerides
Conditions: Chemical in this class must consist of the following general molecular
structure: (COOR)CH2CH(COOR)CH2(COOR), where R is a non-polar, unsaturated,
aliphatic chain. Also, they must not exhibit surfactant properties nor contain reactive
functional groups (e.g., epoxides).
Rationale. Triglycerides are natural biological substances that rapidly metabolized and
are used as an energy source in the human body. Available data indicate there is no
hazard concern for these chemicals.
Qualifying chemicals: soybean oil, olive oil, linseed oil, corn oil, coconut oil,
hydrogenated castor oil, palm oil, and hydrogenated soybean oil.
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