The steam whistle blasted precisely at 10 a.m. today, proclaiming a well-publicized mock disaster at Union Carbide Corp.'s plant here.

But a couple of hundred yards away at West Virginia State College, the short bursts could not be heard indoors. Students in the library did not look up from their books. In the college union building, a young man at a Pac-Man machine never loosened his grip on the joy stick. Some outside mistook the two-minute warning for the sound of a passing train.

The drill was part of an elaborate set of safety preparations being taken for the startup, tentatively set for April 1, of Carbide's methyl isocyanate unit, which has been shut down since a leak in a similar unit at the company's sister plant in Bhopal, India, killed at least 2,000 people on Dec. 3.

Carbide officials gave today's drill mixed reviews, saying that some persons as far as six miles from the plant reported hearing the whistle, while acknowledging that persons indoors may not have been alerted.

Residents were forewarned of the drill by leaflets mailed to 27,000 homes, and advertisements on radio, television and in newspapers.

And today, when the drill began, the word was sent out via emergency announcements on two television and 12 radio stations.

Edward H. Kivett, Carbide's safety director who is also chairman of the Kanawha Valley Emergency Planning Council, an industry-supported organization that sponsored today's test, said the communications phase worked well. "People who heard the whistle knew what to do -- turn on their radio or TV for instructions," and no one panicked. On the other hand, Kivett said, the whistle "did not penetrate buildings nearly as well as we expected," although it was heard outside three to six miles, "farther than expected."

Kivett said it may be necessary to activate the fire alarm at the college in future drills.

He said the council may conduct a simulated evacuation drill in the future. State and local police took up positions along evacuation routes today, but did not set up roadblocks.

At the West Virginia Rehabilitation Center, a residential facility for the physically and mentaly handicapped whose campus adjoins the plant, administrator John P. Williams said the school's 300 students, some of them blind, in wheelchairs or on crutches, had assembled in the gymnasium with 200 staff members before the whistle sounded.

Carbide's board chairman, Warren M. Anderson, told Carbide workers at two meetings in nearby Charleston on Tuesday that the company is "starting down the road" of working with the community to solve the "unique problems" resulting from its location, bordered on one side by a mountain and another by the Kanawha River.