There are 69,000 chemicals in commercial use today and, so far, safe exposure limits have been set for fewer than 1 percent of them. Clearly a Herculean task lies ahead for the regulatory process - that most-favored target of the "too much government" critics. Last Friday, that process labored and brought forth an order suspending use of the pesticide DBCP pending hearings on a permanent ban. How this came about - the history of DBCP since its introduction in the 1950s - says a lot about government regulation: what it can and cannot yet do, and whether it deserves the blanket maligning it is getting.

After a decade of use, DBCP was first registered by the Department of Agriculture in 1961. It had been tested and shown to cause sterility in rats, but only under high doses and prolonged exposure. At the time, regulators looked for immediate, acute effects, and they saw little to worry them in DBCP, Chronic health effects, and the long latencies characteristic of so many forms of cancer were simply not yet recognized as a serious concern. So Agriculture set standards for DBCP's proper use by farmworkers. There was no Occupational Safety and Health Administration (OSHA) then and no one charged with wondering what was happening to workers in the factories making DBCP. Quite separately, the Food and Drug Administration, concerned that consumers might be eating DBCP on their fruits and vegetables, began testing its chronic effects and found that DBCP was a fairly potent carcinogen.

In 1970, the newly created Environmental Protection Agency inherited responsibility for DBCP and a basement full of data on it on thousands of other chemicals. While EPA struggled to keep up with the new chemicals coming on the market, it slowly began reviewing those records. Five years later, the agency flagged DBCP as a potentially dangerous substance, indicating that permission for its continued use was in doubt.

Scientific testing continued, but in 1977 the system was finally jolted into real action by a discovery from an unexpected source. A group of workers at a chemical plant chatting during their lunch hour found a strange coincidence: None of them seemed able to produce children. Half of the workers in the plant, it turned out, were either completely or partially sterile. Within a matter of weeks, OSHA had set exposure limits for workers, FDA began field testing, and EPA suspended the chemical's use on 19 crops where it believed the danger to be highest. EPA also set new standards of use, requiring that a "licensed application" be present. The standards have been widely criticized as unrealistic and inadequate, honored mostly in the breach and offering little protection to those with the least knowledge of the dangers. EPA's tests on field workers found sterility and revealed a direct relationship between sperm count and length of exposure.

As tests with better and better equipment continued, DBCP kept turning up where it was thought not to be. Meanwhile, EPA wrestled with the political process. Congress had directed only that the angency should decide whether use of the pesticide posed "an unreasonable risk" and that it must "balance" whether the health risks (about which more questions remained open than answered) outweighed the$50 million cost of a ban. An apples and oranges problem if ever there was on.

The last straw came a few weeks back. The state of California discovered drinking water contaminated with DBCP. The finding was particularly chilling since DBCP had been banned in that state two years ago. Contaminated water was soon found elsewhere. EPA suspended the chemical's remaining uses.

What does the record show?First, it shows the existence of a growing scientific understanding of chemical dangers, rising standards of care for workers and consumers, and better coordination among agencies and between state and federal government. It also shows little evidence of the overzealous government regulator so popularized of late. But it reveals as well a system with so many built-in checks and balances that, perhaps rightly, it can only move slowly unless some dramatic headline upsets its normal course. Unfortunately for all of us, that dramatic event can mean serious, often irrevocable harm for some. The DBCP story hints, finally, at the tremendous catch-up jobs still ahead and the frightening likelihood of many more DBCPs to come. CAPTION: Illustration, no caption, By Geoffrey Moss for The Washington Post