Tier Action Lead (settled dust) Lead (indoor air)
Screening Basis Screening Basis
Value Value
I Aggressive cleaning. >40 ug/ft2 1) HUD standard >1.5 ug/m3 NAAQS
If levels persist, take for floors (intended to
additional action to 2) Residential keep 99.5 % of
reduce exposure. Lead Hazard childhood
Standard (TSCA population
Section 403) below 30 ug/dl)
II Maintain 25 ug/ft2 (or HUD screening 0.1 ug/m3 to 0.1 ug/m3 is
recommended background) level for floors 1.5 ug/m3 UBK Lead
cleaning methods. to 40 ug/ft2 Model default
Consider additional value for urban
monitoring. background
III No further action <25 ug/ft2 (or HUD screening 0.1 ug/m3 (or Determination
background) level or local background) of local
background background
<need more explanation of methodology>
NYC-WTC_000164846
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NYC-WTC_000164846Source: NYC Law Department, mirrored locally