Older powder formulations contain nonylphenol ethoxylate, a non-ionic surfactant used to provide wetting and increase detergency. This ingredient is petroleum-based and not quickly biodegradable. Phosphates in powdered detergent soften water and aid in the suspension of dirt particles. Phosphates can cause algae formation in ponds and lakes, which can reduce oxygen levels and suffocate plants. Sodium silicate provides alkaline washwater but can be corrosive to eyes and skin. Ethylenediaminetetrsacetate (EDTA) controls hardness but may be carcinogenic.
Most powdered laundry detergents contain ingredients labeled as "optic brighteners." These are fluorescent chemicals that enhance whites so that the clothes appear brighter and cleaner. The brighteners convert ultraviolet light to a blue-white light, providing the illusion of a dazzling, ultra white for your clothes. These brighteners biodegrade slowly and are toxic to some species of aquatic life.
Newer powders contain no phosphates or optical brighteners and are non-toxic and readily biodegradable. Many products substitute vegetable-derived surfactants for petroleum-based products. A good example is alkyl polyglycoside, a biodegradable surfactant derived from the fatty acids of corn or sugar beets. Another environmentally friendly surfactant, linear alcohol ethoxylates, is produced from readily biodegradable primary alcohols. Sodium citrate, formed by citric acid and sodium bicarbonate, safely softens water for better cleaning results.
All powdered formulations use boron and baking powder or sodium bicarbonate to control hardness ions and provide a more efficient cleaning process. Other ingredients may not be as easily identified by the user. Product labels and MSDS may list non-specific items such as fragrance, color protectant, cleaning agent, soil suspending agent, water softeners and fabric brightening agent. Acute effects from exposure to some powders are often listed as transitory or as a result of prolonged contact.