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. Author manuscript; available in PMC: 2014 Apr 28.
Published in final edited form as: Workplace Health Saf. 2014 Feb;62(2):86. doi: 10.3928/21650799-20140121-07

Agency-Hired Hotel Housekeepers

An At-Risk Group for Adverse Health Outcomes

Marie-Anne V Sanon 1
PMCID: PMC4001253  NIHMSID: NIHMS570126  PMID: 24512722

Abstract

Hotel housekeepers experience unique workplace hazards and characteristics that increase their risks for poor health outcomes. Today’s agency-hiring practices may further marginalize hotel housekeepers and negatively impact their health. Yet the impact of such hiring practices on the health of this vulnerable worker group remains unexplored. This article presents the debate regarding agency-hiring practices and how these practices may influence the health and well-being of hotel housekeepers. Implications for occupational health nurses are also discussed.


Agency-hiring practices, an aspect of contingent work, are an emerging trend within the hotel industry with potential for significant health consequences for workers. Hotel housekeepers are the largest workforce within the hotel industry, numbering 1.8 million (Bureau of Labor Statistics, 2013). These workers are particularly vulnerable due to workplace hazards and characteristics. Yet the impact of hiring practices on the health of this vulnerable worker group remains unexplored. Debates on contingent work and workers’ health have focused on workers in general (Cummings & Kreiss, 2008; Guerrina, Burns, & Conlon, 2011; Quinlan, Mayhew, & Bohle, 2001; Virtanen et al., 2005) and less attention has been paid to vulnerable groups including hotel housekeepers. This article provides a brief overview of the discussion around contingent work in general and hotel housekeepers specifically to assess how this marginalized and underserved worker group may experience increased risk for poor health outcomes related to agency-hiring practices.

CONTINGENT WORK

Debates about the efficacy of contingent work have become more frequent in recent years (Benach, Amable, Muntaner, & Benavides, 2002; Benach & Muntaner, 2007; Cummings & Kreiss, 2008; Guerrina et al., 2011). Numbering approximately 43 million or one-third of the labor force in 2005, contingent workers are a major part of the U.S. workforce (Robertson, 2006). With increased globalization and changes in the culture of the labor market, U.S. employers now favor temporary contracts, often to match their fluctuating demand for workers (The Boston Consulting Group, 2012). Consequently, businesses partner with employment agencies to maintain consistent, economical, and accessible labor pools. The impact of contingent work on the labor force is evidenced by the reported 401,000 new jobs provided though private employment services in 2010 (The Boston Consulting Group, 2012) and the $400 billion spent by the U.S. federal government on temporary contractors in 2006 (Shane & Nixon, 2007).

Positive aspects of contingent work include (1) positive transition from education to work; (2) rapid recovery from unemployment to employment status and part-time to full-time work; (3) effective transition between careers and industry; (4) addressing unemployment rates; (5) skill development; and (6) a balanced life with flexibility and autonomy over personal time (The Boston Consulting Group, 2012). However, researchers have become more skeptical of the volatile nature of such hiring practices and have noted the negative impact these practices may have on workers, including their social, financial, and health statuses (Guerrina et al., 2011; Quinlan et al., 2001; Virtanen et al., 2005). However, these reports have failed to provide by-industry details, including the hotel industry.

Contingent Work and Workers’ Health

Contingent workers include agency temporary workers (temps), contract company workers, day laborers, direct-hire temps, independent contractors, on-call workers, self-employed workers, and standard part-time workers (Robertson, 2006). The ease in hiring temporary workers impacts not only the economy but also the health of workers. Studies have reported the negative health impact of contingent work on employees (Quinlan et al., 2001; Underhill & Quinlan, 2011; Virtanen et al., 2005). However, these studies have mostly focused on European workers (Underhill & Quinlan, 2011), indicating the need for further exploration among U.S. workers, and have yet to focus on the health outcomes of contingent hotel housekeepers, the most prominent workers in the hospitality industry.

Quinlan, Mayhew, and Bohle (2001) reviewed 93 studies and found an association between temporary employment and a decline in occupational health and safety. They reported high injury rates, increased disease risks, heightened hazard exposure, and less knowledge of occupational health and safety regulations. Another review of 27 studies (Virtanen et al., 2005) explored the relationship between temporary employment and workers’ health and reported higher psychological morbidity among temporary workers compared to their permanently hired employees. Virtanen et al. (2005) also found higher risk for occupationally related injuries among contingent workers. Thus, contingent work poses a threat to workers’ health and impacts health outcome disparities between contingent and permanent workers.

Several factors may contribute to these health disparities. First, contingent workers are more likely to work at high-risk, low-skill jobs (Guerrina et al., 2011; Hintikka, 2011). Second, contingent workers are more likely to be ethnic minorities and immigrants (e.g., Hispanics) (Cummings & Kreiss, 2008) who often are undocumented, experience language barriers and discrimination, and fear reprisals from supervisors (Salazar, 2006). Another potential contributor to contingent workers’ health risks is their equivocal categorization and inclusion in labor laws and regulations such as the National Labor Relations Act (29 U.S.C. 151), the Employee Retirement Income Security Act (29 U.S.C. 1001), and the Health Insurance Portability and Accountability Act of 1996 (Pub.L.No.104-191) (Robertson, 2006). Compared to the 72% of full-time workers receiving health insurance coverage, only 9% to 50% of contingent workers (depending on type of work performed) enjoy insurance coverage (Robertson, 2006). Moreover, between 17% and 56% of contingent workers have a pension compared to 76% of full-time workers (Robertson, 2006).

AGENCY-HIRED HOTEL HOUSEKEEPERS

Rampant emphasis on globalization, technological advance, and international trade has resulted in a booming hotel industry, nationally and globally. The hospitality industry is the third largest industry in the United States (American Hotel & Lodging Association, 2013). With nearly 5 million guestrooms, a $21.6 billion pre-tax income, and more than $128 billion dollars in revenue, the hotel industry is a prominent contributor to the U.S. economy (American Hotel & Lodging Association, 2012). This industry is driven by increasing competition, high profits, low cost-productivity, and seasonal demand (Freedman & Kosová, 2011). These characteristics are reflected by employers’ attitudes toward employees and their hiring practices regardless of hotel size, type, location, services offered, or chain affiliation.

Hotel Housekeepers

Hotel housekeepers, also known as hotel maids, room cleaners, or housemen, constitute the single largest occupational group within the hotel industry, which employs 1.8 million workers (Bureau of Labor Statistics, 2013; Wial & Rickert, 2002). Hotel housekeepers are disproportionally composed of women of color and immigrants (Lee & Krause, 2002; Wial & Rickert, 2002). Hotel housekeepers and laundry workers occupy the lowest quality jobs within the hotel industry (Wial & Rickert, 2002), as evidenced by their multiple reports of musculoskeletal disorders and other occupationally related injuries (Buchanan et al., 2010; Krause, Scherzer, & Rugulies, 2005) and lack of opportunities for upward mobility both within and between departments (Wial & Rickert, 2002).

Hotel housekeepers often work alone with little interaction with other housekeepers while on the job (Wells, 2000). The annual median earnings of hotel housekeepers ($18,750) falls well below the earnings of housekeepers in other industries, such as hospitals ($22,090) (Bureau of Labor Statistics, 2013).

According to the Bureau of Labor Statistics (2013), the workload of hotel housekeepers results in high injury and illness rates surpassing the national average. The workload involves constant repositioning, changing body postures including bending, kneeling, lifting, stooping, squatting, twisting, and pushing, all of which can potentially lead to sprains and back injuries (Canadian Centre for Occupational Health and Safety, 2007). The workload of hotel housekeepers includes making beds, changing sheets and towels, dusting and polishing furniture, sweeping, waxing or polishing floors, vacuuming, cleaning toilets, bathtubs, windows, and walls, and emptying waste baskets (Bureau of Labor Statistics, 2013).

A paucity of effective approaches to promote and maintain the health of this worker group and decrease their risks for hazard exposures has been reported. On the contrary, changes in the workplace continue to put this worker group at risk. For example, with increased demand for luxury rooms, the work of hotel housekeepers is more complicated. Housekeepers are expected to clean remodeled, yet more intensive areas (e.g., marble surfaces and heavier mattresses) at the same rate (Johnson, 2008; Krause et al., 2005; Seifert & Messing, 2006). Although union organizations such as UNITE HERE have promoted fair and safe work environments for hotel workers, a uniform, universal approach to regulate workload and wages still varies by state and by hotel. UNITE HERE represents more than 100,000 hotel workers in approximately 900 hotels across the United States and Canada (UNITE HERE, 2013). Despite the increase in the number of workers in local unions and periodic success in changing organizational practices (e.g., the agreement between Hyatt and UNITE HERE to increase worker wages) (UNITE HERE, 2013), much work regarding temporary workers remains. In addition, there is a lack of regulations regarding agency-hired workers injured on the job and their benefit coverage.

Hotel housekeepers are exposed not only to physical, but also to chemical, biological, and psychosocial hazards (Table 1) (Hsieh, Apostolopoulos, & Sönmez, 2013). Studies have demonstrated high risks for these workers. For example, in 2010, Buchanan et al. analyzed the Occupational Safety and Health Administration (OSHA) logs of five hotel companies. They found that the reported injury rate for hotel housekeepers (7.9) was higher than for other jobs within these companies. They also determined that the housekeepers had the highest rate of musculoskeletal disorders (3.2 in 100) among all other groups (Buchanan et al., 2010). In addition, Krause, Scherzer, and Ruguiles (2005) explored the prevalence of back and neck pain among 941 hotel housekeepers. Participants reported severe body pain (47%), neck pain (43%), upper back pain (59%), and lower back pain (63%).

Table 1. Hazards Associated With Hotel Housekeeping Work.

Type of
Hazards
Exposures/Risks Examples
Physical Ergonomic related such as sprains,
 pains, and falls
Chemical Cleaning products
Biological Blood and other waste
Psychosocial Coworker support, discrimination

Agency-Hired Hotel Housekeepers

Globalization, international trade, technological advances, and paradigm shifts within the culture of the labor force (e.g., fluctuating seasonal demands) have underscored the industry shift toward agency-hiring practices for hotel employers. Few researchers have addressed the agency-hiring practices specifically among hotel housekeepers. Soltani and Wilkinson (2010) explored the trend of agency-hiring practices within hotel housekeeping departments by interviewing hotel housekeeping managers (n = 42), employment agency managers (n = 21), and agency-hired workers within hotel housekeeping departments (n = 21). They found that cost was the main driver for hotel housekeeping managers. Consequently, temporary workers are at a disadvantage compared to permanent employees hired directly through the hotels in terms of training, pay, career development, and job security. They also found that temporary (flexible) housekeepers were not used efficiently, were less likely to be hired full time by the hotel employer, and felt a sense of isolation and social detachment. Lack of investment in human resources and an overemphasis on cost and labor control is pervasive around the globe within both western and non-western contexts (Soltani, 2008; Soltani, Lai, Phillips, & Liao, 2009).

Agency-hired Hotel Housekeepers and Health

Despite the growing trend toward agency-hired hotel housekeepers, little attention has been paid to potential effects of such practices on their health. An exploration of the existing literature failed to locate any specific studies that explored the direct impact of agency-hiring practices on the health of hotel housekeepers. Yet, current discussions on precarious work in general accentuate the need for such exploration (National Institute for Occupational Safety and Health, 2002). Further exploration of agency-hiring practices and worker health outcomes will not only provide an understanding of the phenomenon but also equip workers, employers, health professionals, and policy stakeholders with the necessary tools to address the practice and counteract the potential negative outcomes that contingent work may have on health.

Several factors affect the health of agency-hired hotel housekeepers and marginalize them. First, agency-hired housekeepers are more likely to earn their compensation based on the number of rooms cleaned per shift (per-room basis) (Oxenbridge & Moensted, 2011). This system provides workers with an incentive to clean more rooms to increase compensation, thus increasing the intensity of their workloads. Consequently, agency-hired hotel housekeepers may be more likely to engage in unsafe work practices to lessen the time per tasks and complete the intended quota (Oxenbridge & Moensted, 2011).

Second, agency-hired hotel housekeepers are hired with lower terms, conditions, and compensation, thus limiting their access to resources compared to in-house housekeepers. For example, in their study of 85 hotel housekeepers (33 of whom were agency-hired), Evans et al. (2007) found that those hired though agencies received lower wages, were more likely to receive little to no holiday pay, and often took on tasks that were beyond their job description for no additional pay. They also found that although two-thirds of the in-house housekeepers were compensated for sick days, less than one-third of the agency-hired workers received sick pay (Evans et al., 2007). Another study of 27 Haitian immigrant hotel housekeepers found that those hired through agencies reported more difficulty managing hypertension, including lack of health insurance (i.e., less benefits compared to the in-house hires), which prevented them from routinely accessing providers and purchasing prescribed medications, and lower wages than in-house hires (Sanon, 2013). Knox (2010) found that hotel employers were attracted to agency-hiring practices because it spared them worker compensation claims. Thus, unless the partnered agency provides compensation for on-the job injuries, the agency-hired hotel housekeeper is left with no coverage and no avenues to access treatment for illnesses and injuries.

Third, agency-hired workers are at risk for psychological distress as they continue to experience conflicts within the workplace. Knox (2010) reported conflicts and a sense of differentiation between in-house staff and agency hires. This risk for psychological distress is also reflected in workers’ reports that employers would rather replace them than invest in their personal and professional development (Knox, 2010). Sanon’s (2013) study also supported this notion of discordance between in-house and agency-hired workers.

Fourth, given their concurrent characteristics as immigrants and individuals of color, hotel housekeepers are vulnerable populations. For example, studies report health disparities among immigrants and individuals of color due to intrinsic (e.g., experiences of discrimination) and extrinsic (e.g., wage discrepancy, policy) factors (Guerrina et al., 2011). Agency-hired work can further marginalize hotel housekeepers because these individuals are more likely to lack resources and experience a heightened sense of objective and subjective job insecurity associated with psychological ill health (e.g., depression) (Ferrie, Shipley, Stansfeld, & Marmot, 2002).

IMPLICATIONS FOR OCCUPATIONAL HEALTH NURSES

Salazar (2006) has noted several ways contingent work can affect occupational health nursing practice and how occupational health nurses can promote contingent workers’ health despite notable challenges:

  1. Increased encounters with and service provision to temporary workers,

  2. Challenges in promoting, maintaining, and monitoring treatment plans due to lack of health insurance,

  3. Improved knowledge of federal laws pertaining to workers’ rights and safety, and

  4. Active involvement in contractual agreements between employers and agencies.

Within this context, occupational health nurses working with agency-hired hotel housekeepers can promote the health of this vulnerable worker group. First, they can aid these workers in understanding occupational health and safety risks. For example, occupational health nurses can develop or tailor culturally appropriate educational programs including those about biological, psychosocial, chemical, and physical hazards to minimize injuries as these workers rush to complete their tasks and reach their quotas. Second, they can provide information about where this group of workers can access resources (e.g., health care coverage) that are not available to them through their employers. Third, they can also partner with hotel employers, particularly housekeeping managers, to determine the best way to maximize productivity, a benefit to the employers, and ways to promote the health and well-being of the workers. Fourth, occupational health nurses can advocate for these workers via policies to regulate partnerships between hotels and the agencies supplying workers (e.g., supply and demand and the individual responsible to provide coverage [e.g., compensation] for these temporary workers).

In addition to the aforementioned clinical implications, this issue has research implications. Studies are needed to explore the health outcomes of agency-hired workers. Ongoing exploration of the factors contributing to agency-hired-workers’ health compared to that of in-house-hired counterparts is needed. Intervention research studies can also promote coworker support and positive coworker dynamics among those hired by both the hotels and agencies.

CONCLUSION

Agency-hiring practices are inevitable among hotels because it has been shown that agency-hired workers demonstrate high productivity and minimal cost while meeting the fluctuating demand for workers in the industry. It has been shown that employers and partnering agencies are more likely to benefit from this arrangement than workers themselves. An unexplored topic is the direct effect of agency-hiring practices on the health of hotel housekeepers. Occupational health nurses should explore these health risks and needs, providing practical approaches to mitigate identified issues and protect the health and well-being of this vulnerable worker group.

IN SUMMARY.

Agency-Hired Hotel Housekeepers

An At-Risk Group for Adverse Health Outcomes

Sanon, M.-A. V.

Workplace Health & Safety 2014;62(2), 81-85.

  1. The impact of agency-hiring practices on the health of hotel housekeepers remain unexplored despite their significant contributions to the growth and sustainability of the industry.

  2. Agency-hired hotel housekeepers are at risk for negative health outcomes and are more vulnerable than their in-house counterparts because of their workloads, which are often based on a per-room payment system, lower or unregulated wages, lack of access to benefits and compensation, and job insecurity.

  3. Occupational health professionals must provide practical measures to address the health needs of agency-hired hotel housekeepers at the individual, organizational, and policy levels.

Footnotes

The author discloses that she has no significant financial interests in any product or class of products discussed directly or indirectly in this activity, including research support.

The author thanks Dr. Robin Evans-Agnew for constructive feedback on an earlier version of this work.

REFERENCES

  1. American Hotel & Lodging Association FAQs. 2012 Retrieved from http://www.ahla.com/content.aspx?id=3114.
  2. American Hotel & Lodging Association Updated: AH&LA responds to recent hotel cleanliness incidents. 2013 Retrieved from http://www.ahla.com/pressrelease.aspx?id=21104&terms=housekeepers.
  3. Benach J, Amable M, Muntaner C, Benavides FG. The consequences of flexible work for health: Are we looking at the right place? Journal of Epidemiology and Community Health. 2002;56:405–406. doi: 10.1136/jech.56.6.405. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Benach J, Muntaner C. Precarious employment and health: Developing a research agenda. Journal of Epidemiology and Community Health. 2007;61:276–277. doi: 10.1136/jech.2005.045237. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Buchanan S, Vossenas P, Krause N, Moriarty J, Frumin E, Shimek JAM, Punnett L. Occupational injury disparities in the US hotel industry. American Journal of Industrial Medicine. 2010;53:116–125. doi: 10.1002/ajim.20724. [DOI] [PubMed] [Google Scholar]
  6. Bureau of Labor Statistics Occupational outlook handbook, Maids and housekeeping cleaners: Pay. 2013 2012-2013 edition. Retrieved from http://www.bls.gov/ooh/building-and-grounds-cleaning/maids-and-housekeeping-cleaners.htm#tab-5.
  7. Canadian Centre for Occupational Health and Safety Occupations and workplace: Hotel housekeeping. 2007 Retrieved from http://www.ccohs.ca/oshanswers/occup_workplace/hotel_housekeeping.html.
  8. Cummings KJ, Kreiss K. Contingent workers and contingent health. JAMA: The Journal of the American Medical Association. 2008;299:448–450. doi: 10.1001/jama.299.4.448. [DOI] [PubMed] [Google Scholar]
  9. Evans Y, Wills J, Datta K, Herbert J, McIlwaine C, May J. ‘Subcontracting by stealth’ in London’s hotels: Impacts and implications for labour organising. Just Labour: A Canadian Journal of Work and Society. 2007;10:85–97. [Google Scholar]
  10. Ferrie JE, Shipley MJ, Stansfeld SA, Marmot MG. Effects of chronic job insecurity and change in job security on self reported health, minor psychiatric morbidity, physiological measures, and health related behaviours in British civil servants: The Whitehall II study. Journal of Epidemiology and Community Health. 2002;56:450–454. doi: 10.1136/jech.56.6.450. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Freedman M, Kosová R. Agency and compensation: Evidence from the hotel industry. Journal of Law, Economics & Organization. 2011 [Google Scholar]
  12. Guerrina RT, Burns CM, Conlon H. Contingent workers. AAOHN Journal. 2011;59:107–109. doi: 10.3928/08910162-20110223-04. [DOI] [PubMed] [Google Scholar]
  13. Hintikka N. Accidents at work during temporary agency work in Finland: Comparisons between certain major industries and other industries. Safety Science. 2011;49:473–483. doi: http://dx.doi.org/10.1016/j.ssci.2010.11.004. [Google Scholar]
  14. Hsieh YC, Apostolopoulos Y, Sönmez S. The world at work: Hotel cleaners. Occupational and Environmental Medicine. 2013;70:360–364. doi: 10.1136/oemed-2012-100986. [DOI] [PubMed] [Google Scholar]
  15. Johnson JV. Services sector. Journal of Safety Research. 2008;39:191–194. doi: 10.1016/j.jsr.2008.02.003. [DOI] [PubMed] [Google Scholar]
  16. Knox A. ‘Lost in translation’: An analysis of temporary work agency employment in hotels. Work, Employment & Society. 2010;24:449–467. [Google Scholar]
  17. Krause N, Scherzer T, Rugulies R. Physical workload, work intensification, and prevalence of pain in low wage workers: Results from a participatory research project with hotel room cleaners in Las Vegas. American Journal of Industrial Medicine. 2005;48:326–337. doi: 10.1002/ajim.20221. [DOI] [PubMed] [Google Scholar]
  18. Lee PT, Krause N. The impact of a worker health study on working conditions. Journal of Public Health Policy. 2002:268–285. [PubMed] [Google Scholar]
  19. National Institute for Occupational Safety and Health . The changing organization of work and the safety and health of working people: Knowledge gaps and research directions. Centers for Disease Control and Prevention; Atlanta: 2002. DHHS (NIOSH) Publication Number 2002-116. [Google Scholar]
  20. Oxenbridge S, Moensted ML. The relationship between payment systems, work intensification and health and safety outcomes: a study of hotel room attendants. Policy and Practice in Health and Safety. 2011;9:7–26. [Google Scholar]
  21. Quinlan M, Mayhew C, Bohle P. The global expansion of precarious employment, work disorganization, and consequences for occupational health: A review of recent research. International Journal of Health Services. 2001;31:335–414. doi: 10.2190/607H-TTV0-QCN6-YLT4. [DOI] [PubMed] [Google Scholar]
  22. Robertson RE. Employment arrangements: Improvement out-reach could help ensure proper worker classification. U.S. Government Accountability Office; Washington, DC: 2006. [Google Scholar]
  23. Salazar MK. Core curriculum for occupational and environmental health nursing. W.B. Saunders Co.; Philadelphia: 2006. [PubMed] [Google Scholar]
  24. Sanon MA. Hotel housekeeping work influences on hypertension management. American Journal of Industrial Medicine. 2013 doi: 10.1002/ajim.22209. Advance online publication. doi: 10.1002/ajim.22209. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Seifert AM, Messing K. Cleaning up after globalization: An ergonomic analysis of work activity of hotel cleaners. Antipode. 2006;38:557–578. [Google Scholar]
  26. Shane S, Nixon R. In Washington, contractors take on biggest role ever. New York Times. 2007 Feb 3; Retrieved from http://www.nytimes.com/2007/02/04/washington/04contract.html?_r=0. [Google Scholar]
  27. Soltani E. Understanding management’s rationale for pursuing labour flexibility: Hotel sector versus employment agencies. 2008. Kent State Working Paper Series. [Google Scholar]
  28. Soltani E, Lai PC, Phillips P, Liao YY. The triangular supply chain relationship: labour dispatch agencies, hospitality sector, and flexible workers: The Taiwan experience. The Service Industries Journal. 2009;29:1317–1339. [Google Scholar]
  29. Soltani E, Wilkinson A. What is happening to flexible workers in the supply chain partnerships between hotel housekeeping departments and their partner employment agencies? International Journal of Hospitality Management. 2010;29:108–119. [Google Scholar]
  30. The Boston Consulting Group . Adapting to change: How private employment services facilitate adaptation to change, better labour markets and decent work. Author; Boston: 2012. [Google Scholar]
  31. Underhill E, Quinlan M. How precarious employment affects health and safety at work: the case of temporary agency workers. Relations Industrielles. 2011;66 [Google Scholar]
  32. UNITE HERE Hotels. 2013 Retrieved from http://www.org/about/hotels.php.
  33. Virtanen M, Kivimäki M, Joensuu M, Virtanen P, Elovainio M, Vahtera J. Temporary employment and health: A review. International Journal of Epidemiology. 2005;34:610–622. doi: 10.1093/ije/dyi024. [DOI] [PubMed] [Google Scholar]
  34. Wells MJ. Unionization and immigrant incorporation in San Francisco hotels. Social Problems. 2000:241–265. [Google Scholar]
  35. Wial H, Rickert J. US hotels and their workers: Room for improvement. 2002 Retrieved from http://www.hotel-online.com/News/PR2002_3rd/Aug02_HotelJobs.html.

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