The leaking methyl isocyanate that killed at least 2,000 people at Union Carbide Corp.'s pesticide plant in Bhopal, India, initially was thought to be water, and a supervisor took a tea break before investigating it, according to The New York Times.

A Carbide spokesman, Tom Failla, said yesterday that "we won't contribute to the speculation" as to the cause of the Dec. 3 tragedy, the worst industrial accident in history, until its own investigation is complete.

But Carbide released some new information as the result of newspaper inquiries. It said a spare tank, which should have been empty so that the deadly chemical could be transferred to it if a leak developed in the primary tank, already contained some methyl isocyanate on the day of the leak. "We do not know when and how the MIC got into the spare tank," the company said.

There had been speculation that the leaking tank had been nearly filled, but Carbide said it had a capacity of 15,000 gallons and contained 11,000 gallons on the day of the accident -- "well below the recommended minimum."

The newspaper said that as a result of a seven-week investigation, which included interviews with present and former Carbide employes, company technical documents and the Indian government's chief scientist, it found evidence of at least 10 violations of standard company procedures and concluded that the leak resulted from a combination of operating errors, design flaws, maintenance failures and training deficiencies.

The source of the runaway chemical reaction, according to the newspaper, may have been water, used two hours before the leak was noticed, to wash an improperly sealed pipe.

The supervisor apparently decided to wait until after his next tea break to investigate the leak because, as one employe put it, "internal leaks never bothered us." Another worker was quoted as saying that he ignored initial readings showing a fivefold increase in pressure in the tank in one hour because the instruments were unreliable.

The newspaper said employes relied on watering eyes to alert them to any escaping chemical, which becomes a gas upon entering the atmosphere, because the plant was not equipped with the computerized monitoring system used at a sister plant in Insitute, W.Va.

But Carbide officials maintain, as they have since initial discussions comparing the two plants, that the computer system at Insitute was used only for data gathering and could not have served to alert employes to a leak.

The Times also said that three key safety systems could not cope with the leak; one had been out of operation for several days, and another had been out of service for maintenance for several weeks. And it said a refrigeration plant used to cool the chemical and inhibit a reaction had been shut down several months earlier.

Carbide said the Bhopal plant had been losing money since 1982, but it would not respond to suggestions that the number and training of employes had been reduced and that some equipment had not been maintained as a result of the financial problems.

Among reasons cited for not responding to most of the points raised by The Times were lawsuits seeking billions of dollars in damages, pending in India and the United States. In addition to the deaths, more than 200,000 people were injured.

A technical team from Carbide headquarters in Danbury, Conn., spent 24 days at the Bhopal plant after the accident but was denied access to certain information by the Indian government, some of which, The Times said, was made available to its reporters.