The Household Hazardous Sweeps (Phase 1) will be performed by the government using certified contractors. For Phase 2 debris removal, property owners can contact the California State Licensing Board to check if a contractor is licensed and insured.  Their telephone number is (800) 321-2752.
The Northern Engineering Contractors Association can provide you a list of contractors that can assist in developing your debris removal plan, including soil assessment and testing.  Their telephone number is (707) 546-5500.
North Coast Builders Exchange also has a list of contractors that can assist in debris removal plans.  Their telephone number is (707) 542-2027.