Having a side hustle is not a new concept. According to the U.S. Census Bureau, workers with more than one job have maintained a steady presence in the country’s workforce since 1970.

Neither is it new for OEHS professionals to monitor for potential exposures that occur in workers’ additional jobs. One example is from early in my career, when I was a Navy reservist in addition to an OEHS professional. Even though my primary employer typically had a strict “no moonlighting” policy, they supported Navy reserve service. Because my employer knew about my other job, my annual physicals included screening for asbestos exposure from my reserve duty, since the Navy was known to have asbestos on its ships.

Workers with multiple jobs or careers present unique challenges to OEHS professionals. Multiple jobholders have been found to be more vulnerable to illness and injury inside and outside of work. They may also experience more fatigue or stress due to competing job demands, gaps in health insurance coverage, or pressures that motivated them to take on more work in the first place. With the practice becoming more widely accepted, OEHS professionals should consider the hazards these workers might encounter outside their primary workplace, where a formal OEHS program may not exist to support them.

DIFFERENT KINDS OF MULTIPLE JOBHOLDERS People take on additional jobs for many reasons, such as to seek fulfillment beyond their “day jobs,” work more flexible hours that allow them to meet family demands, or obtain more job security in a world where employers aren’t perceived to have loyalty to employees. An article titled “Work in Multiple Jobs and Risk of Injury in the U.S. Working Population,” published in 2014 in the American Journal of Public Health, reported that economists cite two main incentives for working more than one job—needing extra income and advancing entrepreneurial skills and opportunities. “These different reasons for multiple job holding, however, are likely not mutually exclusive,” the article states.

For some workers, holding more than one job is a deliberate career choice. People with “slash careers” are generally “those making multiple income streams simultaneously from different careers,” according to a 2017 article in Forbes. The Forbes article explains that a single worker having multiple careers at once used to be associated with creative careers—for example, freelance photographers who are also writers. However, among millennial workers, having multiple careers is becoming more mainstream.

The term “slash career” arises from the slash commonly inserted between the two careers or job titles. Author and speaker Marci Alboher’s 2007 book, One Person, Multiple Careers: The Original Guide to the Slash Career, helped define a slash career and the benefits and challenges of this form of career path.

Guillibeau defines a “side hustle” as “a moneymaking project you start […] usually while still working a day job.” Side hustles can spring from workers’ hobbies or may simply be additional jobs unrelated to their regular employment. They may remain a secondary source of income or be added to a person’s skill portfolio to help them work toward a full-fledged slash career. A podcast titled The Side Hustle Show expands on the ideas in Guillibeau’s book.

There is likely some overlap between slash careerists and gig workers. Gig workers are defined by the human resources consulting company Garter as contingent workers, including independent contractors, freelancers, and contract firm workers, who are in temporary employment relationships and provide project-based, on-demand labor. By hiring gig workers, Garter’s website explains that organizations can “adjust headcounts based on business requirements, access niche skills, and quickly fill talent gaps.” However, gig work tends to be limited in time and not under workers’ control. Gig workers may work multiple jobs to make ends meet or stabilize their sources of income, while slash careerists may take gig jobs to develop specific skills to add to their portfolios.

Other populations related to the phenomenon of multiple jobholders may include students or educators who take on additional work between semesters, seasonal employees, and part-time workers.

WHO WORKS MULTIPLE JOBS? According to the U.S. Census Bureau’s Survey of Income and Program Participation (SIPP) data for 2013, 8.3 percent of the country’s employed population, or about 13 million people, held more than one job that year. That year, the four industries with the highest rates of both male and female workers holding multiple jobs were: • education services and healthcare and social assistance • arts, entertainment, and recreation, and accommodations and food services • professional, scientific, and management, and administrative and waste management services • retail trade

A 2018 study that used data from the 2017 Current Population Survey (CPS), which is sponsored jointly by the Census Bureau and Bureau of Labor Statistics, found that at least 50 percent of multiple jobholders held a full-time job as their main source of employment, plus a part-time job. In comparison, 30 percent of multiple jobholders held two part-time jobs, while only about 5 percent held two full-time jobs. A full-time job is defined as one in which the worker is employed for 35 hours or more per week; a part-time job is defined as one worked for more than one week during the course of a year but for less than 35 hours per week on average. The CPS data also showed that women, workers with advanced degrees, and people with more children are more likely to work more than one job. 

Also in 2018, researchers Mary Dorinda Allard and Anne E. Polivka used data from the U.S. Bureau of Labor Statistics’ American Time Use Survey (ATUS) to find that accounting for informal work, such as income generated from hobbies and crafts, would raise the rate of multiple jobholders by between 3.0 and 20.7 percent. Thus, national estimates about numbers of multiple job holders from the Bureau of Labor Statistics and the Census Bureau may be understating the real number of workers holding multiple jobs.

Despite the differences between data collection methods used for different surveys and by different agencies, Allard and Polivka’s article agreed with both of the previously mentioned studies, as well as a 2021 report that used the Census Bureau’s Longitudinal Employer-Household Dynamics Data, in finding that more women than men work multiple jobs. The 2021 report found that in 2018, 9.1 percent of women and 6.6 percent of men worked more than one job. It also identified a trend for the multiple jobholding rate to decline with age: from 8.9 percent among people aged 16–24, to 5.6 percent for those aged 65 and over.

The COVID-19 pandemic also impacted the number of people working multiple jobs. In July 2022, CBS News reported that the number of people holding multiple jobs had increased by nearly 1 percentage point since the pandemic erupted in 2020. As the Federal Reserve estimated that 4 percent of U.S. workers held multiple jobs in 2020, the rate having declined since previous years, this represents a nearly 25 percent increase. This included an increase in the number of people working two full-time jobs, from 308,000 in February 2020 to 426,000 in June 2022, CBS stated.

The trend toward remote work among white-collar workers, in combination with the effects of the Great Resignation, has likely fueled workers’ interest in side hustles. In a survey of 1,250 full-time remote workers in the U.S., Business Insider reported that two-thirds of the participants said they worked two jobs.

WHY SHOULD OEHS PROFESSIONALS THINK ABOUT SLASH CAREERS? According to the 2014 AJPH article, multiple job holders have a 27 percent higher rate of work-related injury and a 34 percent higher rate of non-work-related injury compared to single job holders. The elevated injury rates suggest greater risk exposures for those who work multiple jobs. Key factors contributing to higher rates of injury among multiple job holders include fatigue from working more than 40 hours a week, mental stress related to task-switching between jobs, lower employer support in occupational health and safety for part-time workers, and job inexperience.

As occupational and environmental health and safety professionals, it should concern us what types of exposures workers with multiple careers might encounter in workplaces that we cannot protect by applying the hierarchy of controls. After-hours firearm instructors are a common example of workers whose side hustles create occupational exposures, specifically exposures to noise and lead. While range safety officers typically monitor for instructors and patrons’ use of eye and hearing protection, they rarely monitor handwashing and tobacco use or check the noise reduction ratings of hearing protection, particularly for the impact noise arising from discharging firearms. Similar issues arise from people who fix cars, clean houses, teach ceramics, landscape, or raise livestock outside their primary work environments, which are under OEHS programs. These types of side hustles create exposures to hazardous chemicals, heat stress, biological hazards, and ergonomics challenges. Fatigue from their second jobs, and from having reduced time to rest, can cross over into their “main careers.”

The “exposome” concept is a helpful tool for looking at the potential exposures that slash careers or side hustles can contribute to a person’s total exposures. NIOSH defines the exposome as “the measure of all the exposures of an individual in a lifetime and how those exposures relate to health.” These exposures begin before birth and include insults from environmental and occupational sources, the agency’s website explains. A side hustle or additional job is likely to add to a person’s lifetime exposures from occupational sources.

PROTECTING MULTIPLE JOBHOLDERS Strategies that can assist OEHS professionals in protecting workers who might have multiple jobs start with understanding their workplaces’ human resources and talent management policies. Unlike in years gone by, when employers prohibited moonlighting, many employers now embrace workers who cultivate their interests into side hustles, since these endeavors tend to create more fulfilled workforces. Slash career blogger Tanya Mimi believes that employers such as startup or high-growth companies are actually looking for slash careerists. “The more experience you have across different areas (for example – data analysis, design, marketing), the more attractive you become to employers,” she writes. “A person with many projects is motivated, focused, and proactive.”

While the conversation about slash careers tends to focus on white collar workers who are seeking fulfillment, many workers take on more than one job to make ends meet. In addition, some employers support workers having multiple jobs in recognition of these workers’ reality. Shivi Thusoo, MBA, CIH, ROH, CSP, the health, safety, and environment manager for a Canadian infrastructure company, shared with me that in the western Canadian oilfield, many field production operators work full time for oil and gas companies, and also run their own farms or help run part of their families’ farms. In some cases, their partners might be the family-run businesses’ primary “employees,” but the field production operators support them during peak periods, such as seeding, harvesting, and calving seasons. In an effort to combat workers’ total fatigue, some oil and gas companies are reducing shift lengths from 10 or 12 hours down to 8 hours. The oilfield operators must expand the number of days they work to achieve a 40-hour work week in their primary jobs, but their employers are seeking to accommodate this very large segment of their workforces.

Thusoo also related that the Canadian healthcare system offers 0.2 and 0.3 full-time equivalent positions. This reduces the costs that employers must pay for employee benefits and promotes job sharing in critical occupations such as nursing. Similarly, the U.S. federal government offers job sharing opportunities for certain positions. These types of employment policies may encourage gig work or slash careers. At the same time, it raises concerns about ensuring living wages, health insurance, and retirement benefits for all workers.

Understanding employers’ policies regarding employees with multiple jobs may provide OEHS professionals with ways of learning about employees’ side hustles and second jobs without violating their privacy. One way that OEHS professionals can offer assistance is by communicating their ability to answer employees’ questions about potential exposures they may encounter in their side hustles or second jobs. Many side hustles are likely to raise few concerns, but establishing open-door policies for sharing information in nonpunitive ways, in cooperation with human resources, legal advisors, and medical professionals, could be another step to take if exposures are a possibility.

Another strategy is to maintain close relationships with supervisors and employees, since many may volunteer information about their side hustles hoping to grow their businesses. OEHS professionals have long supported off-the-job safety and provided tips for seasonal hazards, a practice that may benefit slash careerists and multiple job holders. Being tuned into employees’ side hustles can feed into our profession’s goal to protect all workers.