09013_Mitchell Formal_DMVapor 20050610

C/O CITY OF CHARLOTTE, NEIGHBORHOOD DEVELOPMENT
600 EAST FOURTH STREET, CHARLOTTE, NC 28202
PHONE [phone] - INTERNET www.ncbrownfields.org

NC Brownfields Program – Memo
DATE: June 10 ,2005
TO: Carolyn Minnich
FROM Sandra Moore
SUBJECT: Mitchell Formal Wear , After Hours Formal Wear, Inc.
115B Scaleybark Road, Charlotte, NC
Industrial Hygiene Exposure Assessment Summary
February 2005, performed by ERM
COMMENTS:
The assessment was conducted on January 18, 2005 to evaluate employee exposures to airborne
tetrachloroethylene (PCE). The method used to conduct the study was NIOSH 1003 with a low volume pump. No QA/QC for the analytical data was submitted with the report. At the time of the sampling the facility was
unoccupied and was being used as a storage warehouse. Eight area air samples were taken at four locations and
heights of 2 and 5 feet. An 8-hour TWA PCE exposure was determined.
Questions:
1. Was the HVAC or any other ventilation system in operation at the time of sampling? 2. Were any other constituents analyzed for or detected in the indoor air samples (for example, PCE breakdown
products)?
The results of the indoor air study were compared to the OSHA PELs, ACGIH TLVs and ACGIH BEIs.
Airborne PCE concentrations detected during the study were below these levels. The report states that the applicable standard is the OSHA PEL. However, OSHA PELS are not an appropriate standard for evaluating risk associated with indoor air vapor intrusion at BF sites. One exception to this might be for operations that are
directly regulated by OSHA such as spray booths, plating operations. OSHA PELS are not indices of toxicity and can not be assumed to protect all workers. OSHA PELs assume that workers have been trained in workplace regulations and that the worker is subject to routine biomedical monitoring, as necessary. Regular
office workers who are not trained, who do not have access to protective equipment, and are not protected by other environmental controls in the workplace may be at risk if OSHA PELs are invoked as standards at their
workplace.
Therefore, a risk-based indoor air PCE concentration was calculated for a commercial/industrial exposure
scenario using the equations in the USEPA’s Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air
Pathway from Groundwater and Soils located at http://www.epa.gov/epaoswer/hazwaste/ca/eis/vapor.htm . The calculated value for the commercial/industrial exposure scenario for PCE at a 10-5 or 1/10,000 cancer risk is 13.6
ug/m3. The levels detected in the eight indoor air samples taken at the former After Hours Formal Wear Facility
ranged from 130 to 12,000 ug/m3 and all exceed the calculated risk based value of 13.6 ug/m3.
Based on the information provided in this report, measures are needed at the former After Hours Formal Wear building to reduce indoor air concentrations of PCE to 13.6 ug/m3 or less for an industrial/commercial scenario. For a residential scenario an indoor air concentration of 0.81 ug/m3, which represents a 10-6 or 1/1,000,000
cancer risk, is recommended.
MICHAEL F. EASLEY, GOVERNOR
WILLIAM G. ROSS JR., SECRETARY
DEXTER R. MATTHEWS, DIRECTOR

NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES

DIVISION OF WASTE MANAGEMENT