They are the highly trained, generally well-paid employees in the vanguard of American innovation: people who work in biotechnology labs. But the cutting edge can be a risky place to work. The estimated 232,000 employees in the nation's most sophisticated biotechnology labs work amid imponderable hazards. And some critics say the modern biolab often has fewer federal safety regulations than a typical blue-collar factory. At least three trends are stoking concern among safety advocates. In the wake of the 2001 anthrax attacks, the federal government stepped up research involving biowarfare threats, like anthrax, Ebola and many other of the world's deadliest pathogens. Another factor is that the new techniques of so-called synthetic biology allow scientists to make wholesale genetic changes in organisms rather than just changing one or two genes, potentially creating new hazards. The third trend involves the shifting focus of the pharmaceuticals industry. Drug makers, responding to competition from cheap generic medications, are moving beyond the traditional business of making pills in chemical factories to focus instead on vaccines and biologic drugs that are made in vats of living cells.