WASHINGTON (AP) _ Police and firemen urgently need more training so they can respond properly to accidents involving trucks, trains and barges carrying nuclear materials and hazardous chemicals, congressional researchers say.

''Three-quarters of the first responders are not adequately trained to deal with hazardous substances,'' according to Edith Page, who directed an Office of Technology Assessment study critical of the nation's accident response ability.

''Additional training for public safety personnel in hazardous materials emergency response is urgently needed,'' OTA, a non-partisan congressional research agency, said in the study released Monday.

The researchers warned, however, that dangers to man and the environment don't end with the prompt dispatch of a crack, well-trained response team.

OTA quoted state officials as saying that from 25 percent to 50 percent of the identification placards required on hazardous material shipments are incorrect and that shipping documents identifying a hazardous load ''are sometimes incomplete or inaccessible.''

''Emergency crews must assess the risks of the hazardous material and make decisions on how to respond based on information that may or may not be accurate,'' the study said.

''The wrong response ... endangers both emergency personnel and the neighboring communities,'' said the study, which urged the federal government to establish training and response standards to replace widely varying state requirements.

OTA said the most pressing need is intensified training of safety personnel to handle accidents involving some of the 500,000 shipments of hazardous materials moving daily on highways, rail lines and waterways.

Ms. Page told a news conference that a joke among hazardous response personnel is that you bring tennis shoes and binoculars to an accident - using the shoes to flee to a safe distance and the binoculars to read the placard.

''Then you call for expert help,'' she said. ''This is often said in jest, but there's a strong element of truth in it.''

OTA said that while some states and metropolitan areas have good response programs, ''most first responders in smaller urban and rural areas have not been trained to deal with hazardous materials, despite many existing training programs.

''No national standards for training programs are currently in place, leading to the independent development of different training programs, some of which are inadequate,'' the study said.

Although it did not specifically urge more federal spending, OTA said continued support for state enforcement programs ''is important, since federal inspection forces are shrinking due to budget constraints.''

OTA recommended better training and a national license for operators of vehicles carrying hazardous substances to reduce the average of 11,462 accidents the Transportation Department says occurred yearly between 1973 and 1983.

In most states, Ms. Page said, a truck driver needs no special license for hazardous cargoes. ''The nephew or son of the owner can drive a gasoline truck,'' she said.

Ms. Page said OTA doesn't trust Transportation Department figures that indicate the incidence of accidents involving hazardous materials is decreasing.

''The data collected is so poor we don't know whether things are getting better or worse,'' said Ms. Page, adding that OTA found ''substantial underreporting'' in federal accident statistics.