This chapter considers federalism concerns raised by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) in the context of common law claims for relief following hazardous substance contamination. Congress enacted CERCLA in 1980 to provide a vehicle for the federal government, state and local governments, tribes and private parties to recover costs associated with contamination from releases of hazardous substances that occurred in the past, often decades ago, during a time when there were few requirements for the disposal of hazardous substances. But CERCLA did not provide a remedy for plaintiffs to recover other damages associated with hazardous substance contamination such as lost profits, lost rents, personal injury, diminution in value to property, or punitive damages, instead leaving those damages to be addressed by existing and developing state law. Thus, a central federalism question posed by CERCLA is how the provisions of CERCLA should impact, if at all, state statutory and common law claims to recover damages associated with past releases of hazardous substances. Like most federalism issues involving the impact of federal statutes on state law, the answer is a matter of determining the extent to which Congress intended CERCLA to preempt (that is, displace) state law. This chapter concludes that to the extent state law provides remedies for harm caused by releases of hazardous substances that go beyond the remedies provided in CERCLA, CERCLA should not bar such remedies except to the extent there is a direct conflict between state and federal law. Moreover, where CERCLA is ambiguous, courts should look to the remedial purposes of CERCLA in resolving those ambiguities. This chapter explains these conclusions by exploring (1) preemption of state statutory and common law claims for relief that provide remedies in addition to CERCLA and (2) preemption of state statutes of limitations and statutes of repose that may apply to state law claims for relief associated with hazardous substance contamination.