WTC environmental health assessment draft, May 2002

NYC 9/11 Public Portal Document

Lead

Tier Action Lead (settled dust) Lead (indoor air)

Level Basis Level Basis

I Aggressive >40 ug/ft^ 1) HUD standard >1.5 ug/tn’ NAAQS cleaning. If levels for floors (intended to persist, take 2) Residential keep 99.5 % of additional action to Lead Hazard children reduce exposure. Standard (TSCA chiWheod Section 403) population below 30 ug/dl)

n Maintain 40 ug/ft’ to 25 HUD screening 1.5 ug/m’ to 0.1 ug/m3 is recommended ug/ft^ (or level for floors 0.1 ug/m’ UBKLead cleaning methods. background) Model default Consider additional value for urban monitoring. background

m No further action <25 ug/ft^ (or HLD screening 0.1 ug/m’ (or Determination background) level or local background) of local background background Level could also Level could also be set at that be set at that found in found in background, or background, or unaffected, areas, unaffected, so that no areas, so that no increase in risk increase in risk due to lead due to lead would be would be expected. expected.

<need more explanation ofmethodology>

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CONFIDENTIAL, CITY_21MC100_003423794 SUBJECT TO PROTECTIVE ORDER NO. 2, SEPT. 2008

NYC-WTC_000176165