Tetrachloroethylene levels in residential dry cleaner buildings in diverse communities in New York City

Environmental Health Perspectives, Oct, 2005 by Michael J. McDermott, Kimberly A. Mazor, Stephen J. Shost, Rajinder S. Narang, Kenneth M. Aldous, Jan E. Storm

Fugitive tetrachloroethylene (PCE, perc) emissions from dry cleaners operating in apartment buildings can contaminate residential indoor air. In 1997, New York State and New York City adopted regulations to reduce and contain perc emissions from dry cleaners located in residential and other buildings. As part of a New York State Department of Health (NYSDOH) study, indoor air perc levels were determined in 65 apartments located in 24 buildings in New York City where dry cleaners used perc on site. Sampling occurred during 2001-2003, and sampled buildings were dispersed across minority and nonminority as well as low-income and higher income neighborhoods. For the entire study area, the mean apartment perc level was 34 [micro]g/[m.sup.3], 10-fold lower than mean apartment levels of 340-360 [micro]g/[m.sup.3] documented before 1997. The maximum detected perc level was 5,000 [micro]g/[m.sup.3], 5-fold lower than the maximum of 25,000 [micro]g/[m.sup.3] documented before 1997. Despite these accomplishments, perc levels in 17 sampled apartments still exceeded the NYSDOH residential air guideline of 100 [micro]g/[m.sup.3], and perc levels in 4 sampled apartments exceeded 1,000 [micro]g/[m.sup.3]. Moreover, mean indoor air perc levels in minority neighborhoods (75 [micro]g/[m.sup.3]) were four times higher than in nonminority households (19 [micro]g/[m.sup.3]) and were > 10 times higher in low-income neighborhoods (256 [micro]g/[m.sup.3]) than in higher income neighborhoods (23 [micro]g/[m.sup.3]). Logistic regression suitable for clustered data (apartments within buildings) indicated that perc levels on floors 1-4 were significantly more likely to exceed 100 [micro]g/[m.sup.3] in buildings located in minority neighborhoods (odds ratio = 6.7; 95% confidence interval, 1.5-30.5) than in nonminority neighborhoods. Factors that may be contributing to the elevated perc levels detected, especially in minority and low-income neighborhoods, are being explored. Key words: dry cleaners, environmental justice, PCE, perc, race/ethnicity, socioeconomic status, tetrachloroethylene.

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Tetrachloroethylene (PCE), commonly referred to as perc, is the most frequently used solvent in the dry cleaning industry (Earnest 1996). In New York City and many other urban areas, dry cleaners using perc are sometimes colocated with residences, offices, retail businesses, or food establishments and emit fugitive perc emissions that contaminate indoor air throughout the buildings where they are located (Schreiber et al. 1993, 2002; Wallace et al. 1995). Perc levels in buildings with an operating dry cleaner, or simply near a dry cleaner, have ranged up to 55,000 [micro]g/[m.sup.3] (Altmann et al. 1995; Schreiber et al. 1993, 2002; Wallace et al. 1995).

In the workplace, air perc levels averaging about 30,000-80,000 [micro]g/[m.sup.3] have been associated with alterations in color vision and cognitive function (Gobba 2000), and levels of 1,800-2,400 [micro]/[m.sup.3] have been reported to decrease visual contrast sensitivity (VCS) (Schreiber et al. 2002). Residential indoor air perc levels averaging about 5,000 [micro]g/[m.sup.3] have been associated with small but statistically significant deficits in cognitive performance (e.g., deficits in short-term memory, decreased reaction time) (Altmann et al. 1995), and residential indoor air levels averaging about 700 [micro]g/[m.sup.3] have been associated with decreases in visual function, although decreases were not significant, and residents' function was still within a normal range (Schreiber et al. 2002; Storm and Mazor 2004).

These observations together have raised concern that residents of buildings where dry cleaners are using perc on site (i.e., residential dry cleaner buildings) may experience longterm, involuntary, and possibly harmful perc exposures. Based on this concern and evaluation of visual and other health effects associated with perc exposure, the New York State Department of Health (NYSDOH) derived a health-based guideline of 100 [micro]g/[m.sup.3] perc for residential air, considering continuous lifetime exposure and sensitive people (NYSDOH 1997, 2003). The NYSDOH currently considers this level to be a useful guideline in aiding decisions about the nature and urgency of efforts to reduce residential exposures to perc. Actions to reduce exposure are recommended by the NYSDOH if perc levels ate above background even if they are < 100 [micro]g/[m.sup.3], but an increase in the scale and urgency of such actions is recommended when air levels are > 100 [micro]g/[m.sup.3]. The NYSDOH recommends immediate action when an air level is [greater than or equal to] 1,000 [micro]g/[m.sup.3].

Perc exposures have also been addressed by the federal govermnent. In 1993, the U.S. Environmental Protection Agency issued regulations to control air emissions of perc from dry cleaners (U.S. Environmental Protection Agency 1993). However, these regulations did not specifically address fugitive perc emissions from dry cleaners in residential buildings. Hence, the New York State Department of Environmental Conservation (NYSDEC) and the New York City Department of Environmental Protection (NYCDEP) adopted additional dry cleaner regulations intended to reduce and contain fugitive perc emissions in 1997 and 1998, respectively, which specifically addressed dry cleaners in residential buildings (New York City 1998; NYSDEC 1997). Deadlines for compliance with specific components of the regulations were staggered over several years depending upon the type ("generation") of dry cleaning equipment being used and the type of building (commercial or mixed use) where the dry cleaner was located. The dry cleaner regulations also mandated training and required submission of annual inspection reports by state-approved, third-party inspectors that are used to help document compliance.

Concurrent with adoption of these additional dry cleaner regulations, the NYCDEP and the New York City Department of Health and Mental Hygiene (NYCDOHMH) initiated a process to specifically address complaints from apartment building residents concerned about perc emissions from dry cleaners. Upon receipt of a citizen complaint regarding perc, the NYCDOHMH determines indoor air perc levels in complainants' residences. Depending upon the level of perc detected, the dry cleaning equipment is sealed (perc > 1,000 [micro]g/[m.sup.3]) or a notice of violation to the dry cleaner operator is issued (100 [micro]g/[m.sup.3] < perc < 1,000 [micro]g/[m.sup.3]). In either case, the NYCDEP conducts an on-site investigation of the dry cleaner to determine compliance with dry cleaner regulations and to identify remedial actions required to reduce fugitive perc emissions. This complaint response process is a valuable component of dry cleaner regulation enforcement in New York City while also providing anecdotal information on perc levels in "complaint" buildings.

In 2000, the NYSDOH began recruitment for the New York City Perc Project (NYC Perc Project), a study intended to document perc exposures and possible associated visual function effects among residents of dry cleaner buildings. Indoor air perc levels and biologic (exhaled breath, blood) measures of perc exposure were obtained for residents in buildings with and without dry cleaners, and visual function was assessed using measures of VCS and color vision, previously shown to be adversely affected by perc or solvent exposure (Frenette et al. 1991; Gobba 2000; Iregren et al. 2002; Mergler 1991; Mergler and Blain 1987; Mergler et al. 1987, 1996; Schreiber et al. 2002).