(FORTUNE Magazine) – If all the hands severed last year in industrial accidents were joined thumb to pinkie, how high would they stretch? Higher, possibly, than a ten-story building. ''Possibly'' is about as accurate as such figures ever get, because the Bureau of Labor Statistics doesn't make national estimates of the incidence of specific injuries. Assuming such tallies could be made, who would want them? Labor unions, certainly, since they believe -- but cannot prove -- that the Reagan Administration's lax enforcement of Occupational Safety and Health Administration (OSHA) standards has made the U.S. workplace more dangerous. A second group also wants the data, but not for political ends. Knowing more about injuries could help safety equipment manufacturers. The information could show them how to design better products and might protect them from liability suits. Since worker compensation laws in many states limit the damages an employee can collect from an employer, plaintiffs' attorneys have begun to sue manufacturers. ''We're very sensitive to these suits,'' says Richard H. Prince, vice president of North Safety Equipment, a maker of safety , glasses, hard hats, and respirators. Absent better data, companies are designing products that exceed OSHA standards. E.D. Bullard, the company that invented the hard hat in 1919, introduced a new, harder model on its own initiative. Says Jed Bullard, president: ''OSHA's standards are lagging behind safety technology by several years. We felt vulnerable, so we designed a product based on what we knew was possible.'' Minnesota Mining & Manufacturing took the same course in creating a new generation of respirators. A.F.