Oregon state officials plan to warn the public of elevated levels of arsenic in softshell clams along the Pacific coast, and to suggest consumption limits, says the Salem (Ore) Statesman Journal. An announcement was expected this week, said the newspaper, which obtained documents about the plan. The Oregon Health Authority was to recommend eating no more than four meals a month of whole clams, which had the highest arsenic levels. If the siphon sheaths are removed from clams, as they usually are, more meals per month would be allowed. Wildlife officials say few clamming trips focus on softshell clams. Arsenic is a naturally occurring substance that can, in large quantities, increase the risk of cancer.