California Gov. Gray Davis’s (D) administration yesterday announced controversial new rules restricting use of the pesticide methyl bromide, which is highly toxic to humans and contributes to depletion of the ozone layer. The measures would expand required buffer zones around sprayed areas and require better public notification when the fumigant is used. The state was forced to impose the new regulations by a lawsuit that environmentalists won last year. Still, enviros say the new rules don’t go nearly far enough to protect public health. Under an international treaty to protect the ozone layer, methyl bromide must be phased out from most agricultural uses by 2005 and manufacturers must cut worldwide production by 50 percent next year and 70 percent in 2003.