IN A LETTER published on this page last Sunday, Rep. George Miller (D-Calif.) predicted that passage of the Simpson-Mazzoli bill would result in the temporary admission of a half-million agricultural workers who would take jobs from Americans. His figure is really just a worst-case guess--no one knows with certainty what the real numbers might be--but the problem he raises is a real one.

U.S. immigration laws now allow the temporary admission of workers to perform jobs for which Americans are not available. These are not permament immigrant visas but limited passes to work for a specific time in a specified job. They are called H2 visas and are most widely used to bring in agricultural workers at harvest time. Labor Department regulations make it very difficult to obtain these visas. Employers must certify that they have tried to recruit workers nationwide, that no Americans are available to fill the positions, that housing will be provided for the workers and fair labor standards will be observed. Between 20,000 and 30,000 H2 visas are issued each year, primarily for workers in the eastern states, where they are needed seasonally to pick fruit and cut cane.

Growers in the West do not use the H2 visa program extensively because there is such a large pool of illegal immigrants available to fill agricultural jobs. If the immigration reform legislation now pending in Congress becomes law and sanctions are imposed on those who hire undocumented workers, western growers will have to use the H2 program, and they would like to ease some of the requirements now imposed by the Labor Department. They are willing, for example, to search for American workers in their own region, but believe it is unduly burdensome to have to look throughout the country. They want to be able to bring in foreign workers if they can't find Americans who are not only available, but "able, willing and qualified" for the job. They want to be able to offer housing allowances if they can't supply housing.

Labor organizations want to preserve all the current requirements for the H2 visa, add a few new ones and enact the protective regulations into law. Without such a change, they believe that a flood of cheap temporary labor will take jobs from Americans. The western growers, on the other hand, are certain that tough bureaucratic requirements will leave them without workers at harvest time or will result in skyrocketing food prices. Both sides have legitimate concerns.

The H2 visa program is only a small part of the comprehensive immigration reform package this country so badly needs. Yet stalemate on the question could sink the whole bill. House and Senate subcommittees meeting this week have the difficult but urgent task of reassuring all parties and hammering out an acceptable compromise.