in the early 1990s, starch-based packing peanuts were developed as a more environment-friendly alternative. the starch in the peanuts comes from crop-based sources rather than petroleum-based polystyrene, and is non-toxic. one of the first brands of biodegradable peanuts, biofoam, is made from the grain sorghum; other brands are made from corn starch. biodegradable foam peanuts have no electrostatic charge, another benefit over polystyrene. being biodegradable and nontoxic, they are also safe for humans and pets if ingested accidentally. however, they are not produced in food-safe conditions, and are not recommended for eating. also, during the manufacturing process, the nutritional value is removed from starch-based packing peanuts. this removes edible components, such as sugars, that would otherwise attract rodents and bugs. their main drawbacks compared with polystyrene are lower resilience, higher weight (6.5 to 13 g per litre/0.4 to 0.8 lb per cubic foot), dust creation, potential attraction of rodents, and higher price. starch-based peanuts are soluble in water, and polystyrene peanuts are soluble in acetone, but not vice versa. starch based products can be disposed with down the sink, dissolving on contact with the water.