WASHINGTON - The federal government has filed up to $1.3 billion in environmental cleanup claims against Asarco, a century-old mining and smelting company that sought bankruptcy protection last year amid allegations its Mexican owners had sold off its most lucrative assets. The federal claims represent only a portion of what Asarco may owe its creditors, including at least $500 million in asbestos exposure-related claims and hundreds of millions of dollars more to such states as Washington for their environmental cleanup costs. Tuesday was the deadline for filing the claims with a Connecticut-based claims administrator appointed by the federal bankruptcy judge in Corpus Christi, Texas, who is handling the Asarco case. The federal claims involve 31 Superfund and other sites in 14 states, including Washington, Idaho, Missouri, Kansas, California, Texas and Illinois.