A project of the Massachusetts Department of Public Health’s Occupational Health Surveillance Program,
the Massachusetts Thoracic Society, and the Massachusetts Allergy Society
Massachusetts Department of Public Health, Occupational Health Surveillance Program, 6th floor, 250 Washington Street,
Boston, MA 02108, Tel: (617) 624-5632, Fax: (617) 624-5696
evaluation was to determine if currently employed workers were at risk for developing asthma from exposures at this workplace. Mass SENSOR routinely interviews all occupational asthma cases reported to the program to learn more about the worksite Case History exposures which contributed to the patients’ conditions. For The case involved a 63 year-old male who began working for the some of these cases, worksite evaluations are conducted. Dear Health Care Provider: company in 1989. He was employed as a Ph.D. chemist primarily Worksite evaluations are considered a priority for cases where in charge of quality control testing. His job sometimes involved the asthma trigger is a known or suspected sensitizer and/or the mixing of chemicals, particularly isocyanates. The patient when co-workers appear to be at risk. began experiencing respiratory symptoms soon after beginning In this issue, we present the results of an interesting worksite work at the company. Two years after he began working there, the evaluation. The case, which was reported to Mass SENSOR, patient moved to a new facility. The severity of the worker’s involved a previously unrecognized source of isocyanate respiratory symptoms noticeably increased four years after moving exposure (orthopedic casts) and provided an opportunity for to the new facility. There were no changes in processes, exposure Mass SENSOR to work with the National Institute for controls, or job duties to correspond with this change in symptoms. Occupational Safety and Health (NIOSH) through their Health The patient did not have a pre-existing history of asthma or Hazard Evaluation (HHE) Program. Isocyanates are known allergies and had never smoked. He did not seek treatment until asthma causing agents. 1996 at which time he was diagnosed with new-onset work-related Health Care Providers may request an HHE from NIOSH on asthma. He began taking medication but found that he was behalf of their patients. If you see a case that you believe increasingly sensitive to chemicals in the workplace. By 1997, he warrants a worksite investigation, please let us know when you was no longer able to work and terminated his employment. report the case. Results Sincerely, In December 1999, NIOSH industrial hygienists traveled to the Catharine M. Tumpowsky, MPH workplace to gather information about the facility.
Workplace conditions and processes: The product research and
development activities at both facilities were primarily related to
synthetic orthopedic casting wraps. Job duties of the patient were
similar in both facilities, i.e. developing formulations and Orthopedic Casting Materials: An Unusual Source
troubleshooting products. Interviews with workers indicated that of Isocyanate Exposure exposure conditions at the old facility were worse than those at the new facility based upon qualitative observations. The primary Introduction tasks performed by the patient involved quality control testing of Upon request from employees, employee representatives, or synthetic casting wrap, which contained about 14% MDI (4,4-employers, NIOSH conducts field investigations of potential health diphenylmethane diisocyanate). His tasks included opening the hazards in the workplace. These investigations, called Health product container, dipping the casting wrap in water, and then Hazard Evaluations (HHEs) are conducted to determine whether or wrapping it on appendages of either coworkers or laboratory not any substance normally found in the place of employment has models. The employer required the use of natural rubber latex potentially toxic effects. During the summer of 1998, gloves to protect against skin exposure to isocyanates during cast MassSENSOR received a report of a case of work-related asthma wrapping. The primary exposure potential in the process of in a chemist who had worked for a manufacturer of orthopedic product quality control testing was thought to be when the materials. In November of 1998, after interviewing the patient to packages of casting wrap were opened and casting work was done. learn more about his exposures at the worksite, MassSENSOR requested assistance from NIOSH’s HHE program. In particular,
MassSENSOR requested NIOSH’s assistance in gathering
information about: chemicals in use; severity of inhalation
exposures; the potential for dermal absorption; the adequacy of
ventilation and work practices used to limit exposures. We were
also interested in knowing if the employer had a Hazard REPORT JULY-SEPTEMBER CASES NOW Communication program and employee training related to By October 31st, report all occupational lung disease cases exposures and controls. The specific purpose of the NIOSH seen for the first time between July and September, 1999. If you have NOT seen any cases, it is not necessary to return the
continued on other side SENSOR: Sentinel Event Notification System for Occupational Risk. Massachusetts SENSOR is funded by the National Institute for Occupational Safety and Health.
Traditionally, the industrial hygiene and occupational All work other than casting was conducted within laboratory hoods. medicine communities have centered their research and
intervention efforts on airborne isocyanate exposures. Recent Exposure Monitoring: The company conducted extensive sampling animal studies show that dermal exposures to diisocyanates play an for airborne MDI, all of which indicated non-detectable important role in the development and progression of respiratory concentrations upon analysis. The employer had equipped the sensitization. This finding has yet to be tested in dermally exposed laboratory with a closed-circuit television camera for use when the workers, but may explain why this worker developed asthma in the patient worked with isocyanate-containing products. In the event absence of measurable airborne MDI exposure. that the patient had to work alone in the laboratory, the camera was It is interesting to note that the worker was reported to have used activated by security. The purpose of this self-initiated added latex rubber gloves when exposed to isocyanates. For some security effort was to ensure that assistance could be provided if workers, exposure to latex results in sensitization reactions the worker experienced a severe reaction to the product. The including asthma. No medical information was available to allow patient did not experience such a reaction while working in the NIOSH to determine if a specific agent challenge test was done to laboratories, but was witnessed experiencing milder respiratory establish MDI as the causative exposure. It is plausible that the symptoms at work. Air flow through laboratory hoods was etiologic agent could have been either MDI or the latex gloves. monitored and controlled by a computerized variable air volume The choice of protective gloves should be appropriate for the system designed to increase air flow to each hood in the event of a exposure. Guidelines for glove selection based on the chemical of sensed pressure drop. Supply air for the ventilation system was exposure have been established by the American Society for pulled from the manufacturing area. Testing and Materials (ASTM). NIOSH recommended that the company provide a laminate glove for protection against skin Hazard Communication: The employer had an extensive Hazard exposure to MDI. Natural rubber latex gloves of the thickness Communication Program in place both while the patient was commonly used with medical supplies provide poor protection for employed and when NIOSH visited the workplace. Interviews exposure to organic chemicals that permeate through the material indicated that the Hazard Communication Program did not include very quickly. a teaching unit specific to isocyanates, but did include information about where to find information on the chemicals with which the laboratory researchers worked. Interviewed co-workers were aware of the hazards associated with isocyanate exposure. Wheezing at Work Other cases: A literature search was conducted and one case The Massachusetts Nurses Association, with funding from related to the use of orthopedic casting products was identified as the Department of Industrial Accidents, has developed a was a case of skin sensitization related to the use of isocyanate-training program for nurses and other health care professionals containing casting products. who suffer from latex allergy or work-related asthma. Two training sessions will be offered on November 8, 1999 Discussion at Olympus Specialty Hospital in Springfield, MA. For more The most common and debilitating health effect associated with information, please call Susan Clish in the MNA Nursing isocyanate exposure is respiratory sensitization. This condition is Department at 800-882-2056, X723. indistinguishable from asthma, and is commonly referred to as isocyanate-induced asthma; i.e. a generalized airway obstruction
that is usually reversible. Prevalence estimates for isocyanate-
induced asthma in exposed worker populations vary from 5 – 30%. A worker with this disease will present with acute symptoms of asthma; e.g. coughing, wheezing, shortness of breath, tightness in
Number of Work-Related Asthma Cases Reported the chest, and nocturnal awakening. After sensitization, any
exposure to isocyanates, even to levels below any occupational to Massachusetts SENSOR, March 1992- June 1999 exposure limit or standard, can produce an asthmatic response, which may progress to respiratory distress. This asthmatic reaction April May June Total to Date may occur minutes after workplace exposure (immediate), hours 1999 1999 1999 (3/92-6/99) after exposure (late), or a combination of both immediate and late 61* 6 1 711 components after exposure (dual). The percentage of sensitized
workers with persistent symptoms of asthma after years of no *The majority of these cases came from one occupational health clinic which isocyanate exposure may be 50% or higher. Studies have shown reports to Mass SENSOR on a quarterly basis. that workers with persistent asthma have a significantly longer duration of symptoms prior to diagnosis, larger decrements in pulmonary function, and a severe degree of nospecific bronchial hyperactivity at diagnosis. Hypersensitivity pneumonitis (allergic alveolitis) has been described in workers exposed to diisocyanates,
but is considered a rare event.