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Federal Register Notice: March 29, 1990 Revisions to the Toxicity Characteristic Final Rule

With this March 29, 1990 Federal Register notice, EPA finalized revisions to the hazardous waste toxicity characteristic. The rule retains many of the features of the June 13, 1986 proposal including:

  • replacing the Extraction Procedure leach test with the Toxicity Characteristic Leaching Procedure (TCLP);
  • adding 25 organic chemicals to the list of toxic constituents of concern; and
  • establishing regulatory levels for these organic chemicals based on health-based concentration thresholds and a dilution/attenuation factor that was developed using a subsurface fate and transport model.

In response to comments received on the proposed rule and related notices, this final rule incorporates a number of modifications in the leaching procedure, the list of toxicants, the chronic toxicity reference levels, and the fate and transport model.

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