The U.S. Occupational Safety and Health Administration (OSHA) has certified these Water Crystals to be non-hazardous. The product has been certified under 29CFR1910.1200. OSHA does recommend that consumers use "good agricultural hygiene" when using them. In other words, don't mix the crystals with any kind of liquid that may endanger your plants or crop.
Water Crystals are inert. They will not be absorbed into plants or migrate into ground water.
Water Crystals fill and release. With rain, normal watering, or crop irrigation, the crystals expand to capture and retain excess moisture in the soil. This property reduces run-off. When they dehydrate or empty through feeding roots, their shrinkage causes the soil to naturally aerate, reducing compaction and hardness. Water Crystals have been shown to be 95% effective for as long as 12+ years in soil.