Indoor COCs benchmark levels discussion, March-April 2002

Z Z FINAL (Octoto 11,2001) ATSDR, CDC, ERA, OSHA Environmental Assessment Workgroup Asbestos Action Levels for World Trade Center Response o o io Action Level & Analysis Method

NYC Background’ PCM/PCMe’ f/cc General PublitVRecommendations'

• No restriction on access to anyarea. Supporting hformation’

AHERA standards (40 CFR Comments

• Remediation goal is to adiieve background levels. ♦ co

■D I c o (see footnotes 2 and 3) 763); ATSDR Toxicological • AHERA guidance for schools requires that when schools are remediated for CT o o Profile for Asbestos; OSHA asbestos, the indoor air levels ofasbestos should besimilar to local outdoor air o' o U co 29 CFR 1926.1101 levels. o 3. • Lowest attainablecancer risk 91 CD O NYC Background to 0.01 fee PCM/PCMe' • No restriction on access to streets and public/ AHERA standards (40 CW • No significant cancer risk for short-term occupancy for residential and o o commercial building; continue to monitor 763); ATSDR Toxicological school buildings. c 3 ------ • Evaluate to determine if tong-tom access is acceptable; Profile for Asbestos; RIS; • AHERA guidance for schools requires that when schools are remediated for CD

I evaluate trends over months. OSHA 29 CFR 1926.1101 asbestos, the indoor air levels ofasbestos should besimilar to local outdoor air ■ Identify source levels ■ Take action, as practical, to reduce levels to background

70 structures/mm- TEM • If < than 70 s/nm\ no restrictions on access to buildings AHERA standards (40 CW • AHERA standards applyonly to schools, and byNYC ordinance to • If > 70 s/mm^ resample to confirm and analyze field 763) buildings. blanks; takeaction to identify source and reduce levels to < NYC Clearance standard for • Method sensitivity and counting rules should follow Appendix A (Table I) 70 s/mm- buildings in AHERA 40 CFR 763; Method sensitivity based on # grids analyzed and air sample volume and must be maintained at 0.005 fee.

0.01 -0.1 fee PCM/PCMe’ • Continueto monitor; consider the need for additional Lowest limit set at 1/10 • Long-taro exposures may inaease cancer risk in the general public sampling sites. PEL/REI7TLV; AHERA • Unlike workers the general population, indudes children and sensitive • If air levels are consistaitly between 0.01 to 0.1 fee, standards (40 CW 763); persons, does not receive exposure monitoring and dos not participate in annual evaluate the need for advisories, the need to limit ATSDR Toxicological Profile health screening access and the need for dust suppression.. for Asbestos; RIS; OSHA 29 CFR 1926.1101;

>0.1 Pec PCM/PCMe’ • Evaluate the need to restrict general public access. Unacceptable cancer risk General public should not beexposed to levels suspected of adverse health • Continue to monitor; consider the need for additional following longterm effects upon longterm exposure sampling sites.. exposure; AHERA standards (40 CFR 763); ATSDR Toxicological Profile for Asbestos; RIS; OSHA 29 CFR 1926.1101

Action levels (f/cc) for workers involved in Disaster Response and Recovery Workers Basis Comments emergency response and recovery activities (follow applicable OSHA standards)

0.1 PCM only • Respiratoryprotection required for workers, based on an 8 PEL Value, 0.1 fee based on an eight hour time weighted average, is the hour time weighted average (TWA) of exposure of 0.1 PCM. Occupational Safety and Health Administration’s (OSHA) Permissible Longer shift work, i.e., tower levels ofexposure Exposure; Limit for asbestos, as specified in the OSHA Construction Industry Regulation for Asbestos, 29 CW 1926.1101.