Strawman benchmarks for indoor contaminants of concern, March 2002

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o FINAL (October 11, 2001) ATSDR, CDC, EPA, OSHA Environmental Assessment Workgroup Asbestos Action Levels for World Trade Center Response o i 1^ Action Level & Analysis Method

NYC Background’ PCM/PCMe' f/cc General Public/Recommendations'

• No restriction on access to any area. Supporting Information’

AHERA standards (40 CFR Comments

• Remediation goal is to achieve background levels. co

U o 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 29 asbestos, the indoor air levels of asbestos should be similar to local outdoor air cn U CFR 1926.1101 levels. O oo 3. Ca5 • Lowest attainable cancer risk 03 CD

NYC Background to 0.01 f/cc PCM/PCMe’ • No restriction on access to streets and public/ AHERA standards (40 CFR • No significant cancer risk for short-term occupancy for residential and school o o o commercial building; continue to monitor 763); ATSDR Toxicological buildings. c • Evaluate to determine if long-term access is acceptable; Profile for Asbestos; IRIS; • AHERA guidance for schools requites that when schools are remediated for 3 Q evaluate trends over months. OSHA 29 CFR 1926.1101 asbestos, the indoor air levels of asbestos should be similar to local outdoor air 3

■ Identify source levels ■ Take action, as practical, to reduce levels to background

70 structures/mm’ TEM • If < than 70 s/mm’, no restrictions on access to buildings AHERA standards (40 CFR • AHERA standards apply only to schools, and by NYC ordinance to buildings. • If > 70 s/mm’, resample to confirm and analyze field blanks; 763) • Method sensitivity and counting rules should follow Appendix A (Table 1) in take action to identify source and reduce levels to < 70 s/mm’ NYC Clearance standard for AHERA 40 CFR 763; Method sensitivity based on # grids analyzed and air sample buildings volume and must be maintained at 0.005 f/cc.

0.01 - 0.1 f/cc PCM/PCMe’ • Continue to monitor; consider the need for additional Lowest limit set at 1/10 • Long-term exposures may increase cancer risk in the general public. sampling sites. PEiyRElTTLV; AHERA • Unlike workers the general population, includes children and sensitive persons, • If air levels are consistently between 0.01 to 0.1 f/cc, standards (40 CFR 763); does not receive exposure monitoring and does not participate in annual health evaluate the need for advisories, the need to limit ATSDR Toxicological Profile screening access and the need for dust suppression.. for Asbestos; IRIS; OSHA 29 CFR 1926.1101;

>0.1 f/cc PCM/PCMe’ • Evaluate the need to restrict general public access. Unacceptable cancer risk General public should not be exposed to levels suspected of adverse health effects • Continue to monitor; consider the need for additional following long-term exposure; upon long-term exposure. sampling sites.. AHERA standards (40 CFR 763); ATSDR Toxicological Profile for Asbestos; IRIS; OSHA 29CFRI926.II01

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

1.0 PCM only • The maximum allowable level for workers average over 30 STEL Value, 1.0 f/cc measured over a 30-minute period, is the Occupational Safety and minute period (OSHA short term exposure level). Health Administration’s (OSHA) Short-Term Exposure Limit for asbestos, as • PPE required above 1.0 f/cc PCM. specified in the OSHA Construction Industry Regulation for Asbestos, 29 CFR 1926.1101.

1. General public includes adults and children not directly involved in emergency response and recovery activities. 2. Documents and information that were considered in setting the action level. 3. Background levels for NYC ate being determined. 4. PCM equivalents (PCMe) is determined using TEM analysis and counting fibers > 0.3 ^zm in diameter and > 5 pm in length. PCMe should be determined using consistent methods to provide comparable concentrations. If PCM is exceeded, may need to determine PCMe using TEM. Use professional judgement to determine if PCMe is needed by evaluating the frequency and magnitude of exceedance, size of geographic area involved, and trends in data.