THREE months after 19,000 gallons of pesticide spilled into the Sacramento River, a state study shows the area's aquatic life will take 20 to 50 years to recover.A Southern Pacific train car carrying the toxic chemical metam-sodium derailed July 14, poisoning 45 miles of river and devastating fish, wildlife, and plants. "The basic gist of the report is that we have ourselves a nonfunctioning ecosystem," says Banky Curtis, Regional Manager for the California Department of Fish and Game, which released the findings. Virtually all aquatic life was destroyed, including the fish, algae, and insects that were essential food sources for everything from aquatic and terrestrial animals to birds. Since toxins from the spill were dissipated or removed within one week of the derailment, between 30 and 60 botanists as well as 300 volunteers have been assessing impacts. "The complex of interrelationships is so profound that we now have an entire bioregion that simply can't function the way it did," says Gary Stacey, environmental supervisor for the Department of Fish and Game. Loss of one insect species may affect the pregnancy rates of bats, for instance. Loss of fish means depleted food supplies for heron, egret, otter, merganser, and water oozle. The report shows that insects, algae, and moss are recovering most quickly, though full restoration will take 3 to 5 years. Species of trout and suckerfish are estimated to take 10 to 15 years to reach pre-spill levels. Forest alongside the river - where 40- to 50-year-old willows and cottonwoods were affected - will be the slowest to recover. For court cases that are to follow, ongoing studies will try to assign a dollar estimate to such damages. Impact estimates will include decreased recreational and tourist use. Southern Pacific has been charged with causing the accident by improperly sequencing its rail cars and using a locomotive that was inadequate to pull them. Though state officials say the state will seek to recover maximum compensation from Southern Pacific, railroad spokesman Mike Furtney says the firm has admitted no liability whatsoever. Claims may be filed also against the builder of the tank car carrying the pesticide and other parties involved in the shipping process, according to Mr. Curtis. Curtis and other agency officials have said the multiagency response to the spill was first-rate and cooperative. Those who first reached the spill site, however, were significantly delayed for lack of knowledge about the dangers of the chemical. The United States Environmental Protection Agency (EPA) has acknowledged that its failure to list the health hazards of metam-sodium contributed to the delay both in getting cleanup measures started and in warning residents. Rep. Barbara Boxer (D) of California, head of the House government operations subcommittee investigating the accident, is still inquiring whether or not Southern Pacific personnel may have caused the spill by puncturing the train car while trying to remove it from the river. "We are examining apparent inconsistencies between dispatcher transcripts and later testimony by Southern Pacific officials," says staffer Tim Morrison. Ms. Boxer also has introduced three bills or amendments since the spill. One requires the Department of Transportation (DOT) to adopt a broader list of hazardous materials - including metam-sodium - currently used by the US Coast Guard. Another requires DOT to list chemicals that threaten the environment rather than just those considered injurious to humans. A third would tighten reports to federal authorities on safety. "We were on the scene within 30 minutes, but we had a major problem knowing what the chemical was," says Mr. Stacey. "There was nothing we could do to deal with it." "We are moving to identify those chemicals that are toxic to the environment but are not currently regulated by DOT," says Jim Jones, assistant administrator to Linda J. Fisher, the EPA's administrator for toxic substances. "The process which led to this situation needs to be fixed," Ms. Fisher said in testimony before the House panel. "EPA is extremely concerned about ... gaps in regulatory coverage that have been revealed by this incident."