thesynergist | NEWSWATCH
IARC: Firefighters’ Exposures Cause Cancer
The International Agency for Research on Cancer in July announced the classification of occupational exposure as a firefighter as a Group 1 carcinogen, the agency’s designation for agents that carry sufficient evidence of carcinogenicity in humans. A working group of 25 international experts convened by IARC concluded that there is sufficient evidence for mesothelioma and bladder cancer associated with firefighters’ occupational exposures. The group also noted limited evidence for firefighting’s association with colon cancer, prostate cancer, testicular cancer, melanoma of the skin, and non-Hodgkin lymphoma. The number of firefighters worldwide exceeds 15 million, according to IARC. Firefighters face a variety of occupational exposures, including combustion products from fires like polycyclic aromatic hydrocarbons, volatile organic compounds, metals, and particulates; diesel exhaust; and building materials such as asbestos. Other hazards can include heat stress, shift work, and ultraviolet and other radiation. Exposure to flame retardants in textiles and chemicals in firefighting foams, including synthetic chemicals like per- and polyfluoroalkyl substances (PFAS), is also of concern. IARC noted that firefighters often rely on personal protective equipment such as self-contained breathing apparatus but that “dermal absorption of chemicals can occur even in firefighters wearing PPE due to limitations of its design, fit, maintenance, or decontamination.” When IARC previously assessed the carcinogenicity of firefighting in 2007, the agency classified it in Group 2B as “possibly carcinogenic to humans.” Since then, new studies examining the association between occupational exposures among firefighters and cancer risk in people have been conducted. IARC’s new evaluation of firefighting considers 52 cohort and case-control studies, 12 case reports, and seven meta-analyses. According to the agency, some of the most informative research included more than 30 non-overlapping cohort studies that followed firefighters for cancer over time in Asia, Europe, North America, and Oceania. There are approximately 1.1 million firefighters in the United States, according to NIOSH. An agency study completed in 2015 of nearly 30,000 firefighters found higher rates of several types of cancers than in the U.S. population as a whole. The rate of mesothelioma among the study population was twice as high as in the general population, likely due to firefighters’ occupational exposure to asbestos. The study also found higher incidence of cancers of the respiratory, digestive, and urinary systems among firefighters. Within the study cohort, the amount of time spent at fires correlated to increased chance of lung cancer diagnoses, and the chance of death from leukemia increased with the number of fire runs. In 2018, Congress passed legislation requiring the establishment of a National Firefighter Cancer Registry to monitor incidence of cancer among firefighters. The voluntary registry is being established by NIOSH and was expected to begin accepting registrations in autumn of this year. For more information, visit the NIOSH website. NIOSH resources related to firefighters and cancer are also available from the agency. A summary of IARC’s evaluation is available online in The Lancet Oncology. The full article is available free of charge to registered users (registration is also free). Further details are available in an IARC press release (PDF). IARC’s detailed assessment of the carcinogenicity of firefighting will be published next year in Volume 132 of the IARC Monographs series.
NIOSH to Assess Fatigue in Oil and Gas Extraction
A new project proposed by NIOSH would evaluate sleep and fatigue among oil and gas extraction workers and examine these and other factors’ relationship to risks in the industry. Researchers plan to measure sleep and alertness among workers; gather information related to demographics, working hours, commute times, and sleep quality; and interview workers, supervisors, subject matter experts, and others regarding the challenges related to fatigue management. According to NIOSH, worker fatigue is commonly associated with nonstandard work schedules, stress, physically and mentally demanding tasks, and working in hot environments. Fatigue can result in slower reaction times, affect cognition and sleep, and contribute to numerous negative health effects, including cancer, cardiovascular disease, and psychological disorders. Investigations have found that worker fatigue has been a contributing factor to high-profile disasters, including the Three Mile Island nuclear meltdown and Exxon Valdez oil tanker accidents. For more information, read the Federal Register notice.
New Toxicological Profile Published for Ethylene Oxide
A new final toxicological profile for ethylene oxide (EtO) is available from the Agency for Toxic Substances and Disease Registry. EtO is a flammable gas used to make the chemical ethylene glycol, which in turn is used to make antifreeze and polyester. EtO is also used to sterilize food products as well as medical equipment and supplies in hospitals or sterilization facilities. Workers who perform routine sterilization of equipment in hospitals or other workplaces may be exposed to relatively high levels of EtO, and those who work where EtO is made or used are also at risk of exposure via inhalation or contact with the skin. Individuals who live near industrial facilities that release EtO may be exposed to higher levels of the gas than those who live elsewhere.
ATSDR warns that workers exposed to high levels of EtO in air for short time periods reported lung irritation. Those exposed to high concentrations for both short and long periods reported effects including headaches, memory loss, numbness, nausea, and vomiting. According to OSHA, acute exposures to EtO gas may also result in lung injury, diarrhea, shortness of breath, and cyanosis, a condition characterized by bluish discoloration of the skin, usually due to deficient oxygenation of the blood.
“Chronic exposure [to EtO] has been associated with the occurrence of cancer, reproductive effects, mutagenic changes, neurotoxicity, and sensitization,” OSHA’s website explains.
The U.S. National Toxicology Program has determined that EtO is known to be a human carcinogen (PDF). EPA also considers EtO to be a human carcinogen.
The new toxicological profile for EtO can be found on the ATSDR website.
National Academies Recommends Testing for PFAS Exposure
A report released in August by the National Academies for the Sciences, Engineering, and Medicine (NAS) recommends that people in certain occupations and who live in areas contaminated with perfluoroalkyl and polyfluoroalkyl substances (PFAS) should have their blood tested to determine the extent of their exposure. Those whose PFAS exposure levels are associated with increased risk of adverse health effects should receive regular screenings, the report states.
PFAS are a group of synthetic chemicals that were in widespread use for decades in consumer products and across industries. PFAS exposure is associated with increased risk of lowered antibody response, high cholesterol, decreased infant and fetal growth, and increased risk of kidney cancer, according to the NAS report. Their persistence in the environment has earned PFAS the nickname “forever chemicals.”
Intended to inform CDC guidance to clinicians, the NAS report says that PFAS blood testing should be offered to patients who are likely to have a history of elevated exposure, a group that includes people who work in fluorochemical manufacturing, electroplating, painting, carpet installation and treatment, firefighting, and in jobs that require handling of ski wax. Food workers and others in the hospitality industry who handle food packaging as part of their jobs may also have elevated exposure to PFAS. People who live in areas known to be contaminated with PFAS should also be tested, according to the report.
The report can be downloaded as a free PDF from the NAS website. For more information, read the NAS news release and visit an interactive website that explores findings from the report.
NIOSH: Approved Respirators Cannot Be Altered to Improve Fit
Concerns regarding the user instructions for several filtering facepiece respirators (FFRs) manufactured by NIOSH approval holders prompted the agency to publish a notice stressing that agency-approved respirators cannot be altered to improve fit. According to the notice, NIOSH has identified some statements instructing users to modify FFRs—for example, by tying knots in the headbands to create a tighter fit. The agency cautions users that some FFRs with instructions containing similar statements were distributed when NIOSH failed to identify the concern before issuing approvals. NIOSH says that it is notifying approval holders to correct their user instructions as issues are identified. NIOSH’s notice reminds those who are required to use respiratory protection in occupational settings that if a user cannot achieve a proper fit, the respirator configuration should not be modified in any way. Instead, another product should be selected for use, the agency says.
Heat Checklist Added to Handbook for Small Businesses
The Small Business Safety and Health Handbook, a publication developed by NIOSH and OSHA to provide information on implementing workplace safety and health programs for employers with small businesses, was recently revised to include a checklist for the prevention of heat-related illnesses. The handbook also includes self-inspection checklists that employers can use to identify hazards for various work processes in general industry workplaces, including fire protection, hazard communication, and respiratory protection as well as issues related to permit-required confined spaces and noise exposure.
The revision to the handbook comes a few months after OSHA implemented the first-ever National Emphasis Program intended to protect U.S. workers from heat illnesses and injuries. The NEP aims to improve OSHA’s enforcement and compliance efforts related to heat and involves the agency proactively initiating inspections in more than 70 high-risk industries when the National Weather Service issues heat warnings or advisories in local areas. Earlier, in October 2021, OSHA published an advance notice of proposed rulemaking to start the process of creating a federal heat standard. According to the Department of Labor’s regulatory agenda, OSHA is analyzing the comments it received from the ANPRM.
The Small Business Safety and Health Handbook is available on NIOSH’s website. Topic pages from OSHA on working in outdoor and indoor heat environments and from NIOSH on heat stress provide further resources related to heat hazards.
Study Evaluates PPE Use Among Healthcare Workers Exposed to Monkeypox
A study of Colorado healthcare workers found low adherence to CDC recommendations for personal protective equipment when caring for patients with suspected or confirmed monkeypox, according to a publication in the agency’s Morbidity and Mortality Weekly Report. From May 1 through July 31, researchers with the Colorado Department of Public Health and Environment evaluated exposures among 313 healthcare workers caring for patients who were later diagnosed to have monkeypox infections. Only 23 percent of the healthcare workers wore all recommended PPE, which includes respirators, gloves, gowns, and eye protection. In addition, among the 87 workers whose exposures were determined to be of intermediate or high risk, fewer than half opted to receive a vaccine for monkeypox.
Despite the low adherence to CDC’s recommendations, none of the exposed healthcare workers contracted monkeypox during the 21 days researchers monitored them. Six workers developed symptoms, but their PCR test results were negative. A seventh worker’s symptoms were linked to a reaction to a medication. According to the report, the absence of transmission in these cases is consistent with previous outbreaks in the United States and with reports of cases imported from other countries, which have shown that occupationally acquired monkeypox is unlikely when infection prevention and control recommendations are followed. Still, the lack of adherence to PPE recommendations in this study suggests that better training is needed for frontline healthcare workers, the researchers conclude.
As of Sept. 30, there were approximately 26,000 confirmed cases of monkeypox in the current U.S. outbreak, with one death, according to CDC data. More information about monkeypox for healthcare professionals is available from the agency's website.
EPA Proposes to Designate PFOA and PFOS as Hazardous Substances
A new proposed rule would designate two perfluoroalkyl and polyfluoroalkyl substances (PFAS) as hazardous substances under CERCLA, the Comprehensive Environmental Response, Compensation, and Liability Act. The rule would apply to perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), as well as their salts and structural isomers.
Designation as a CERCLA hazardous substance requires entities responsible for PFOA and PFOS to immediately inform federal, state, and local authorities of any release of these chemicals that meets or exceeds the “reportable quantity.” EPA has set the reportable quantity for PFOA and PFOS at one pound in a 24-hour period. Entities potentially affected by the rule include manufacturers and processors of PFOA and PFOS, manufacturers of products that contain these chemicals, downstream manufacturers and users, and waste management and wastewater treatment facilities.
For more information, download the rule as a PDF.
Study on Cancer Burden: Asbestos Exposure Remains a Leading Risk Factor
Occupational exposure to asbestos is among the top risk factors contributing to the burden of cancer worldwide, according to research published Aug. 20 in The Lancet. The research is based on the 2019 iteration of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD), a long-running project led by the University of Washington that provides estimates of global health for causes of death and disability and their associated risk factors.
The GBD uses disability-adjusted life years, or DALYs, to estimate the burden of cancer attributable to more than 80 risk factors. According to the 2019 iteration of GBD, the leading age-adjusted risk factors contributing to worldwide cancer burden in 2019 were almost identical to those in 2010. Occupational exposure to asbestos ranked seventh in both years, with 61.1 DALYs per 100,000 person years in 2010 and 50.9 DALYs per 100,000 person years in 2019. The percentage change of 16.7 DALYs for occupational asbestos exposure was the largest drop among the top ten risk factors but not enough to change its position in the rankings.
For more information about the GBD, see "By the Numbers" in this issue or the website of The Lancet.
EPA Revises Risk Determination for Pigment Violet 29
A revised risk determination finalized by EPA on Sept. 6 finds that pigment violet 29 (PV29) presents an “unreasonable risk of injury to human health,” particularly for long-term inhalation exposure. PV29 is used as an intermediate to create or adjust color of other perylene pigments and is incorporated into paints and coatings used in the automobile industry, plastic and rubber products used in automobiles and industrial carpeting, and in merchant ink for commercial printing and in consumer watercolors.
Long-term exposure to PV29 in air can cause lung toxicity effects such as alveolar hyperplasia, which is “an adverse increase in the number of cells in the lungs where oxygen transfer occurs,” EPA notes. The revised risk determination differs from previous risk evaluations of PV29 in that it represents a “whole chemical determination” instead of separate determinations for individual conditions of use, and does not assume that all workers exposed to the chemical substance always or properly wear personal protective equipment.
EPA intends to develop a risk management rule for PV29 to protect workers who handle the chemical while on the job.
For more information, read the revised risk determination, EPA’s press release, and its risk evaluation webpage for PV29.
Valley Fever a Concern for Wildland Firefighters in the Southwestern U.S.
A recent outbreak of Valley Fever, or coccidioidomycosis, among wildland firefighters highlights the importance of respiratory protection and training to better protect these workers. According to an article published in the Aug. 26 issue of CDC’s Morbidity and Mortality Weekly Report, seven firefighters who came down with respiratory illness in the summer of 2021 each visited an emergency department two or three times due to cough, chest pain, or shortness of breath. Three firefighters who were hospitalized tested positive for coccidioidomycosis and were treated with antifungal medication.
Valley Fever is caused by the inhalation of Coccidioides fungal spores, which are present in the soil of semiarid areas such as Arizona and California in the southwestern United States as well as parts of Mexico and Central and South America. The disease can cause fatigue, cough, fever, shortness of breath, headaches, body aches, joint pain, and rash. Severe cases can result in hospitalization or death.
The firefighters were likely exposed to Coccidioides while responding to a fire near the Tehachapi Mountains, which form part of the boundary between the San Joaquin Valley and the Mojave Desert. The firefighters dug trenches and “mopped up” the fire, tasks that involved digging and moving soil “with heavy dust exposure and without respiratory protection,” according to MMWR. The report urges fire agencies to evaluate the feasibility of respirator use under certain conditions—during dust-generating activities away from active burning, for example.
The MMWR report is available from CDC’s website.
IARC Releases Monograph on 1,1,1-Trichloroethane, Other Industrial Chemicals
The International Agency for Research on Cancer has classified the industrial chemical 1,1,1-trichloroethane as a Group 2A carcinogen, the agency’s designation for substances that are probably carcinogenic to humans. IARC’s evaluation of research on 1,1,1-trichloroethane concluded that positive associations exist between exposure and the blood cancer multiple myeloma. The findings appear in a new edition of the agency’s monographs series. A previous IARC monograph published in 1998 had designated 1,1,1-trichloroethane as Group 3, or not classifiable as to its carcinogenicity to humans.
1,1,1-Trichloroethane was widely used as a degreasing solvent in the 1970s and 1980s, and it was an ingredient in many household products such as adhesives, lubricants, glues, and fabric finishes. By the early 2000s, the chemical was used almost exclusively as a precursor in the manufacture of hydrofluorocarbons.
The potential for occupational exposures to 1,1,1-trichloroethane occurred in its manufacture as well as in industries that used it for cleaning furniture, metal products, and electronic equipment, and in industries where the chemical was used in the manufacturing of paints, inks, and aerosol and adhesive products.
The new monograph also assesses 1,2-diphenylhydrazine, previously used globally as a precursor in the production of dyes; diphenylamine, a component of lubricants, greases, metalworking fluids, and other products; n-methylolacrylamide, which is used in the manufacture of polymers with acrylic and vinylic monomers; and isophorone, a widely used solvent and chemical intermediate. IARC classifies all four of these substances as Group 2B, possibly carcinogenic to humans.
The new volume of the IARC monographs series is available on the agency’s website.