1.  Regarding its public housing inventory (under Section 9 of the Housing Act of 1937; see Lead Safe Housing Rule subpart L), per the New York City Housing Authority Lead Action Plan, January 21, 2020, sec. B.1, pars. 1 and 3, p. 4:

      NYCHA owns and operates 172,447 apartments in 2,291 buildings across 311 developments.  Of these, approximately 134,000 apartments across 277 developments are in buildings constructed prior to 1978. ...  
      
      ... [Discussion of lead-based paint inspection procedures in multi-unit buildings] ...
      
      In the 2000s, NYCHA retained qualified vendors to conduct LBP inspections pursuant to the HUD Guidelines. Through this testing initiative, NYCHA identified 92 developments as having at least some LBP components in their apartments, and 277 developments as having at least some LBP components in their common areas. ....

As noted, about 134,000 apartments are in pre-1978 buildings and may have lead-based paint.  If needed for the Agency's analysis, the number of apartments that have lead-based paint may be estimated by multiplying that number by the fraction of pre-1978 developments with apartments that have some LBP components, i.e., 92/277 (33.2%), yielding (rounded to thousands, as in the 134,000 estimate), about 45,000 NYCHA public housing apartments with lead-based paint.

2.  Regarding NYCHA's project-based rental assistance (PBRA) housing inventory (under Section 8 of the Housing Act of 1937; see Lead Safe Housing Rule subpart H), HUD's Inventory Management/Public Housing Information Center (IMS/PIC) system shows, through its HA Profiles Details website (https://pic.hud.gov/pic/haprofiles/haprofiledetails.asp) (selecting for New York State and then NYCHA's HA Code of NY005) that NYCHA's section 8 inventory as of 9/17/2020 included 104,145 housing units.  This inventory is reasonably expected to be older than NYCHA's public housing inventory, which, as above, has 89% of its developments being of pre-1978 construction.  It is reasonable, therefore, to estimate that all of NYCHA's section 8 inventory is of pre-1978 construction.  

Unlike NYCHA's public housing inventory, its PBRA inventory was not the subject of HUD lead-based paint removal efforts in the 1970s and forward.  Accordingly, the estimates from the American Healthy Homes Survey I (AHHS I, conducted in 2005-2006) Table 4-1 on lead-based paint prevalence can be used:  First, for the Northeast Census Region, in which New York is located, 60.5% of housing units built before 1978 had lead-based paint, and, second, the relative prevalence of lead-based paint in Government-supported housing is 74.6% of that in housing overall; combining these yields an estimate of 45.1% of Government-supported Northeast housing having lead-based paint.

Assuming, as above that NYCHA's 104,145 PBRA housing units are pre-1978 and of them, 45.1% have lead-based paint, yields an estimate (rounded to thousands) of about 47,000 NYCHA PBRA units with lead-based paint.

3.  For the New York City Department of Housing Preservation and Development (HPD), for which its HA Code is NY110, HUD's IMS/PIC database's HA Profiles Details website (URL above) shows HPD's section 8 inventory, which is primarily housing choice voucher units (see Lead Safe Housing Rule subpart M), as of 9/12/2020 as 37,353 housing units.  Using the same housing age and Government support characteristic factors as in section 2 above, it is estimated that 45.1% of the 37,353 units, or (rounded to thousands) about 17,000 HPD housing choice voucher units have lead-based paint.
