California farmers are increasing their use of pesticides and other carcinogenic and harmful chemicals, according to a new study by the watchdog group Pesticide Action Network. In the first comprehensive investigation into pesticide use in California, the group found that more than 50 million pounds of harsh chemicals were applied to California farm fields in 1998 — an increase of 3 million pounds since 1994. In November, 150 residents of the farm town Earlimart had to be evacuated when a cloud of metam sodium, a suspected carcinogen being sprayed by a growing number of farmers, drifted over their neighborhood, and two dozen of them were hospitalized for burning eyes, vomiting, shortness of breath, and other problems. Strawberry growers are among the most heavy chemical users in California, while many growers of grapes and tree fruits like oranges are cutting back on their use of chemicals.