Title V of the Clean Air Act Amendments of 1990 require thousands of major industrial sources of air pollution to seek operating permits from local or state authorities. The Environmental Protection Agency's (EPA's) Pollution Prevention in Permitting Program (P4), begun in 1993 under Title V, seeks to encourage, through a structured process of permit negotiations, the technological innovations required to achieve pollution prevention. A close look at three such negotiations, involving Intel, Lasco Bathware, and Cytec Industries, reveals that P4 did, indeed, push firms to pursue pollution prevention more aggressively and achieved a better balance between the concerns of EPA and state regulators and the interests of the regulated companies than might otherwise have been achieved. Whether the negotiated permitting process also led to greater levels of pollution prevention than might otherwise have been achieved, however, it is not possible to say.