ON MONDAY, November 13, the National Cancer Institute (NCI) identified ethylene dibromide (EDB) as the most potent cancer-causing substance ever found in the 300 chemical NCI animal test program. Yet, aware of this finding, professors allowed the use of EDB in Tuesday and Wednesday (November 14 and 15) afternoon Natural Sciences 3, "Introduction to Chemistry," labs.

On Wednesday, November 15, the Nat Sci 3 staff found a successful alternative chemical, methylene chloride, which was used exclusively in the lab starting Thursday. The staff deserves credit for the quick action taken to find a substitute for EDB. But it was irresponsible to needlessly expose students to this suspected human carcinogen in the Tuesday and Wednesday labs.

Nat Sci 3 professor Bennie R. Ware, associate professor of Chemistry and Veronica Vaida, assistant professor of Chemistry, rightly point out that the high-dose NCI animal study does not conclusively prove that low levels of EDB can cause cancer in humans. But the scientific community is currently debating he validity of extrapolating animal carcinogencity data to humans. This debate is far from resolved, and many scientists feel that the discovery of potent cancer-causing ability in animals must be taken as strong presumptive evidence for a human cancer threat. That's the reason why NCI did its animal study in the first place.

In light of this uncertainty, and the unprecedented carcinogenicity displayed by EDB in the NCI animal study, it would seem that Ware and Vaida were taking temporary chances with other peoples' health, for the sake of an introductory chemistry lab. Their decision disregarded NCI's conclusion that its findings indicate a potential threat to human health.

Ware and Vaida also seem to take the position that the laboratory hazards are simply a part of laboratory work and that singling out EDB for scrutiny is unfair since it fails to take into account the many other hazards necessarily present in all labs, including the Nat Sci 3 lab. But teaching laboratories can be made safe, or at least safer than they are now, and they should be.

Ware and Vaida correctly contend that if handled properly, EDB is probably safe. But inexperienced students can not be expected to possess flawless laboratory technique. Science students must learn to deal with lab hazards, but they need not be exposed to risks they are not yet prepared to handle safely: training student scientists in a teaching laboratory with carcinogenic chemicals is like training bomb squads with live explosives.

In one respect we wholeheartedly agree with Professors Ware and Vaida: it is unfair to single out EDB without considering all the other potential hazards of the laboratory. Considering the attitude demonstrated in the case of EDB, it seems to be time for a thorough, independent review of all health and safety hazards in Harvard's research and teaching laboratories.