DfE Screens for Safer Chemical Ingredients

The DfE Program provides a unique, highly protective approach to review and recognition of safer products. DfE evaluates each ingredient in a formulation based on critical health and environmental endpoints and within its functional class (e.g., surfactants, solvents). The functional class context allows DfE to view ingredients as part of a continuum of improved or safer ingredient choices.

DfE General Screen for Safer Ingredients

In establishing thresholds for green ingredients, the General Screen delineates the safer or “low-concern’ end of the ingredient spectrum, guiding and ensuring best-in-class ingredient choices for DfE-recognized products. With the development of the General Screen, the core of the DfE review process and the standard to which it applies is transparent and ready for third-party implementation.

All components in DfE-recognized products will be screened against the general screen or against any component-class screens, as available and appropriate. Component-class screens define and more fully explore the green end of specific ingredient-class continuums. Using the general screen as a template, the component-class screens tailor the health and environmental endpoints in the general screen in a way appropriate to the specific class, designating key, distinguishing characteristics and adjusting thresholds, as necessary. Developing the screens improves the general understanding of the characteristics of safer ingredients in the class and helps identify green-chemistry opportunities and successes.

Each ingredient in a formulation has a role to play in making a product work. Whether it is to aid in cleaning by reducing surface tension (surfactants), dissolve or suspend materials (solvents), reduce water hardness (chelating agents), or provide a scent (fragrances), each ingredient type has a function. Within these "functional classes," many ingredients share similar toxicological and environmental fate characteristics. As a result, DfE focuses its review of formulation ingredients on the key (environmental and human health) characteristics of concern within a functional class. This approach allows formulators to use those ingredients with the lowest hazard in their functional class, while still formulating high-performing products.

From the beginning of the Formulator Program (started in 1997), DfE has used the technical expertise of its workgroup of EPA scientists to compare ingredients in the same functional class and thereby identify those ingredients with the safest hazard profile. The program is now developing DfE Screens for safer chemical ingredients to share this expertise and make it easier to formulate safer products. The screens were developed to identify safer chemical ingredients for cleaning products.

The DfE General Screen for Safer Ingredients (PDF) (15 pp, 141K, About PDF) is available here as a pdf document.

DfE Screen for Solvents in Cleaning Products

With cleaning solvents, there are potential concerns for the following endpoints: carcinogenicity, acute mammalian toxicity, reproductive and developmental toxicity, repeated-dose toxicity, neurotoxicity, and environmental fate and toxicity. Phase I of the solvents screen should be applied only to alcohols, esters, ethylene glycol ethers, and propylene glycol ethers. DfE’s next step is to expand the solvents screen to additional solvent classes used in cleaning products, such as terpenes, amines, and amides; these will be known as Phase II solvent classes.

DfE is interested in gaining experience with Phase I of the solvents screen as it is applied by DfE and third-party reviewers for CleanGredients, and will use that experience to inform future iterations of the screen. The DfE Screen for Solvents (PDF) (16 pp, 130K, About PDF) is available here as a pdf document.

PHASE I SOLVENT CLASSES	Alcohols Esters Ethylene Glycol Ethers (EGEs) Propylene Glycol Ethers (PGEs)
ATTRIBUTES OF CONCERN FOR PHASE I SOLVENTS	Carcinogenicity Neurotoxicity Acute Mammalian Toxicity Reproductive and Developmental Toxicity Repeated-Dose Toxicity Environmental Fate and Toxicity

DfE Screens for Surfactants

Surfactants in cleaning products are distinguished by their rate of biodegradation and level of aquatic toxicity. The DfE Screen for Surfactants combines those two hazard characteristics, and requires that surfactants with higher aquatic toxicity demonstrate a faster rate of biodegradation. Surfactants that meet the relevant screen for product use are acceptable for use in a DfE-recognized cleaning product.

Standard Surfactant Screen

Acute Aquatic Toxicity (L/E/IC50 Value)¹	Rate of Biodegradation
≤1 ppm	May be acceptable if biodegradation² occurs within a 10-day window without products of concern³
>1 ppm and ≤10 ppm	Biodegradation² occurs within a 10-day window without products of concern³
>10 ppm	Biodegradation² occurs within 28 days without products of concern³

1. In general, there is a predictable relationship between acute aquatic toxicity and chronic aquatic toxicity for organic chemicals, i.e. chemicals that have high acute aquatic toxicity also have high chronic aquatic toxicity. Since acute aquatic toxicity data are more readily available, the DfE Screens use these data to screen chemicals that may be toxic to aquatic life.
2. Generally, >60% mineralization (to CO2 and water) in 28 days.
3. Products of concern are compounds with high acute aquatic toxicity (L/E/IC50 ≤ 10ppm) and a slow rate of biodegradation (greater than 28 days).

Certain products that are intended for use outdoors are likely to bypass sewage treatment, shortening the time for degradation prior to entering sensitive environments. For these products, like boat cleaners and graffiti removers, DfE has raised the bar in its standard surfactant screen to address the potential for immediate contact with aquatic life. Any ingredients (including surfactants, preservatives, solvents, etc.) that have aquatic toxicity values <1 mg/L are not allowed in DfE-recognized direct release products.

Surfactants Screen for Direct Release Product

	Acute Aquatic Toxicity Value (L/E/IC50)¹	Persistence (Measured in terms of rate of biodegradation)	Status
1	≤1 ppm		Not acceptable
2	>1 ppm and ≤10 ppm	Biodegradation² must occur within a 10-day window without products of concern³	Could be improved
3	>10 ppm and <100 ppm	Biodegradation² occurs within 28 days without products of concern³	Could be improved
3	>10 ppm and <100 ppm	Biodegradation² occurs within a 10-day window without products of concern³	Acceptable
4	≥100 ppm	Biodegradation² occurs within 28 days without products of concern³	Acceptable

1. In general, there is a predictable relationship between acute aquatic toxicity and chronic aquatic toxicity for organic chemicals, i.e.
chemicals that have high acute aquatic toxicity also have high chronic aquatic toxicity. Since acute aquatic toxicity data are more readily available, the DfE Screens use these data to screen chemicals that may be toxic to aquatic life.
2. Generally, >60% mineralization (to CO2 and water).
3. Products of concern are compounds with high acute aquatic toxicity (L/E/IC50 ≤ 10ppm) and a slow rate of biodegradation (greater than 28 days).

Formulators who subscribe to the CleanGredients® database can find a list of surfactants and a developing list of solvents that meet the DfE Screens. Suppliers who subscribe can have their chemicals reviewed against the screen and listed in the database. Nearly 300 formulators are finding safer surfactants on CleanGredients®.