Federal regulators have set a safety level for the industrial chemical melamine in infant formula... and are urging consumers to keep using U.S.-made formula.Officials for the food and drug administration set a threshold of one part per million of melamine in formula, so long as a related chemical isn't also present.Under the new threshold, the amount of melamine found in FDA testing is now defined as safe.The safety level is far below the amount of melamine found in infant formula in China, which has been blamed for killing at least three babies and making thousands ill.