5.2.4.5 Ultrasound

5.2.4.5.1 Hazard location

Ultrasound is the mechanical vibration of an elastic medium that is produced in the form of alternating compressions and expansions. The vibration may be produced by continuous or impulse sound in the form of a sequel of interrupted vibrations. The medical uses of ultrasound include therapeutic surgical, and diagnostic procedures.

5.2.4.5.2 Potential health effects

Although exposure to ultrasound does not appear to pose a human health risk, exposure to audible high-frequency radiation above 10 kHz can result in a syndrome involving nausea, headaches, tinnitus, pain, dizziness, and fatigue. Temporary hearing loss and threshold shifts are also possible from high-frequency ultrasound radiation.

Low-frequency ultrasound radiation may produce local effects when a person touches parts of materials being processed by ultrasound. The hands are often involved in the area where ultrasound acts most strongly. Exposure to powerful sources of ultrasound may result in damage to peripheral nervous and vascular structures at the points of contact. Airborne ultrasound vibration may produce effects on the central nervous system and on other systems and organs through the ear and through extra-auditory routes.

5.2.4.5.3 Standards and recommendations

No OSHA standard or NIOSH recommendation exists for ultrasound. ACGIH has proposed the following TLVs for permissible exposure to airborne upper sonic and ultrasonic acoustic radiation (ACGIH 1987):

5.2.4.5.4 Exposure control methods

Exposure to ultrasonic vibration can be reduced by the use of enclosures and shields. Sound-isolating panels on ultrasonic equipment should be free of any openings and should be isolated from the floor by rubber seals. Workers operating or repairing ultrasonic equipment should be provided with appropriate protective equipment that is selected based on the task being performed and the likelihood of exposure to radiation above 10 kHz or to contact with low-frequency sources.

5.2.4.6 Video Display Terminals

5.2.4.6.1 Hazard location

Video display terminals, VDTs have rapidly replaced other word processing and data management systems in many hospital departments.

5.2.4.6.2 Potential health effects

VDT’s are a frequent source of worker complaints. Eyestrain, back, neck, and arm discomfort, and symptoms of stress have all been associated with VDT work. These problems may be controlled or improved with ergonomic measures such as adjusting the position of the screen and keyboard, the chair, the lighting and glare, the color contrast, and the frequency of rest periods. Whether long-term VDT use causes significant visual dysfunction or degeneration is unknown. Extensive radiation measurements and health data have indicated that VDT's do not appear to present a radiation hazard to the operators (Pomroy and Noel 1984) or to the developing fetuses of pregnant operations (NIOSH 1984a). However, clusters of miscarriages and birth defects have been reported among VDT operators and warrant further investigation (NIOSH 1984a).

5.2.4.6.3 Recommendations

NIOSH studies have resulted in a report entitled Potential Health Effects of Video Display Terminals (NIOSH 1981h) which contains specific recommendations for the installation, maintenance, and use of VDT's. NIOSH recommends the following general guidelines for VDT work (NIOSH 1984a).

Workstation design: VDT units, supporting tables, and operator chairs should be designed with maximum flexibility. VDT's should have detachable keyboards, and work tables should be adjustable for height. Chairs should be adjustable for height and should provide proper back support.

• Illumination: Sources of glare should be controlled through VDT placement, i.e. parallel to windows, and parallel to and between lights, proper lighting, and the use of glare-control devices on the VDT screen surface. For VDT tasks requiring screen-intensive work, illumination levels should be lower than those needed when working with hard copy, which may require local lighting in addition to normal office lighting.

• Work regimens: Continuous work with VDT's should be interrupted periodically by rest breaks or other work activities that do not produce visual fatigue or muscular tension. As a minimum, a break should be taken after 2 hr of continuous VDT work. Breaks should be more frequent as visual, mental, and muscular burdens increase.

• Vision testing: VDT workers should have visual testing before beginning VDT work and periodically thereafter to ensure that they have adequately corrected vision to handle such work.

5.3 MUTAGENS and TERATOGENS

5.3.1 Introduction

Measures for locating mutagens and teratogens, controlling worker exposures, and conducting medical surveillance of exposed workers are also discussed by specific agent in Section 4 and in the other subsections of Section 5.

Health care workers may be exposed to a number of agents that are considered to be mutagenic or teratogenic. These agents include the following (Yager 1973):

Biological agents


Rubella virus
Cytomegalovirus
Hepatitis B virus

Chemicals


Ethylene oxide
Organic solvents

Pharmaceuticals


Anesthetic gases
Antibiotics
Cytotoxic drugs

Physical agents


Ionizing radiation

5.3.2 Effects of Exposure

Estimates indicate that up to 4 million women employed in hospitals may be exposed to reproductive hazards (Kooker 1987). Lists of teratogenic agents present in the hospital environment have been compiled by Beckman and Brent (1986) and Schardein (1985). Despite the presence of known human teratogens in the hospital, there is no clear evidence that exposure conditions in hospitals have resulted in an excess rate of birth defects among the offspring of hospital workers. For example, cytomegalovirus is recognized as a human teratogen, but exposed nursery and pediatric care personnel do not appear to be at increased risk of cytomegalovirus-induced birth defects (U.S. Congress 1985).

A number of studies have supported more general associations between employment in hospitals or laboratories in general, and an increased risk of adverse reproductive effects, primarily spontaneous abortion. For example, spontaneous abortions and birth defects have been associated with exposure of female operating room personnel to waste anesthetic gases; a similar relationship was also suggested for the wives of exposed men (NIOSH 1977a). Exposure to sterilizing agents, primarily ethylene oxide, has also been associated with increased frequencies of spontaneous abortions (Hemminki et al. 1982) and with chromosomal abnormalities in circulating lymphocytes (Hogstedt et al. 1983; Laurent et al. 1984).

5.4 DERMATOLOGICAL HAZARDS

5.4.1 Introduction

Skin injuries and diseases account for a large proportion of all occupational injuries and diseases (ASPH/NIOSH 1988). Skin injuries in the hospital environment include cuts, lacerations, punctures, abrasions, and burns. Skin diseases and conditions of hospital workers include dermatitis, allergic sensitization, infections such as herpes, and skin cancer. In 1984, dermatologic diseases accounted for more than 34% of all chronic occupational illnesses in the United States. Of workers who develop a dermatologic disease, 20% to 25% lose an average of 11 working days each year. In the service industries, which include the health service industry, nearly 8,000 cases of dermatologic diseases were reported to the Bureau of Labor Statistics in 1984 -- an incidence of 5 cases per 10,000 fulltime workers (ASPH/NIOSH 1988).

5.4.2 Hazard location

Skin problems among hospital workers have been associated with work in every part of the hospital, but they are especially common among housekeeping personnel, maintenance workers, orderlies, and aides. In one hospital, 60% of the workers with occupational dermatitis of the hands were aides and housekeepers, even though these two categories made up only 17% of the total workers in the hospital (Dahlquist and Fregart 1970). Half of the workers with dermatitis had suffered with the skin problem for 6 months or more.

The NIOSH publication Occupational Diseases: A Guide to Their Recognition (NIOSH 1977d) contains an extensive list of occupational irritants and causes of dermatologic allergy. Listed below are some of the common causes of skin problems for some categories of hospital workers:

5.4.3 Potential Health Effects

Chemicals can directly irritate the skin or cause an allergic sensitization. Physical agents can also damage the skin, and skin that has been chemically or physically damaged is vulnerable to infection.

5.4.3.1 Effects of Chemical Agents

Skin reactions, dermatitis, are the most common and often the most easily preventable of all job-related health problems. The skin is the natural defense system of the body: it has a rough, waxy coating, a layer of protein, keratin, and an outer layer of dead cells to help prevent chemicals from penetrating the tissues and being absorbed into the blood.

5.4.3.1.1 Direct irritation

Many chemicals cause irritation on contact with the skin, irritant contact dermatitis, by dissolving the protective fats or keratin protein layer, dehydrating the skin, or killing skin cells. Symptoms of this kind of irritation are red, itchy, peeling, dry, or cracking skin. Some chemicals are not irritants under normal conditions, but they will irritate skin that has already been damaged by sunburn, scratching, prolonged soaking, or other means. Tars, oils, and solvents can plug the skin pores and hair follicles, causing blackheads, pimples, and folliculitis.

Irritant contact dermatitis is diagnosed by a history of contact with a chemical and by the improvement or disappearance of symptoms when contact is discontinued.

Data from California (ASPH/NIOSH 1988) suggest that the following five types of agents are responsible for the greatest number of workers’ compensation claims:

• Soaps, detergents, cleaning agents

• Solvents

• Hard, particulate dusts

• Food products

• Plastics and resins

5.4.3.1.2 Allergic contact dermatitis

Some persons become sensitized to chemicals days, months, or even years after their first exposure. This allergic reaction does not occur in every worker who contacts the chemical. Symptoms are red, itchy, and blistering skin, like a poison oak or ivy reaction, and may be much more severe than the direct irritation described in the previous subsection.

Sensitization is usually diagnosed by a history of contact and by patch testing, in which a physician applies a small amount of the suspect chemical to the skin under a patch to observe the reaction over 48 hr. Workers who are sensitized to a chemical will usually continue to have severe reactions unless all contact is prevented by substituting another chemical or transferring to another job. Common contact allergens include (ASPH/NIOSH 1988) the following:

• Metallic salts (i.e. salts of nickel, chrome, cobalt, gold, mercury)

• Rubber accelerators and antioxidants (these may leach from rubber gloves) such as thiurans, dithiocarbamates, mercapto compounds, and paraphenylenediamine derivatives

• Plastic resins such as epoxies, phenolics, and acrylics

• Organic dyes such as those in photographic color-developing solutions

• First aid cabinet preparations such as neomycin, themerosal, and benzocaine

• Common laboratory chemicals such as phenol and formaldehyde.

5.4.3.2 Effects of Physical Agents

The skin can be damaged in a variety of ways including:

• Mechanical trauma (i.e. cuts lacerations, abrasions, punctures)

• Burns from physical agents, electricity, heat, or UV radiation

• Chemical burns

Although there are no data describing skin injuries among hospital workers specifically, data from the Bureau of Labor Statistics for 1983 indicate that almost 10% of the workers’ compensation claims for skin injuries from 30 reporting states occurred among cooks and food service workers (ASPH/NIOSH 1988).

5.4.3.3 Skin cancer

The association between basal and squamous cell carcinomas and ultraviolet radiation has been well established. The association between skin cancer and exposure to other agents is less well documented, but ionizing radiation and antineoplastic drugs have been implicated. Other evidence indicates that malignant transformation of cells damaged by chronic allergic contact dermatitis may occur (ASPH/NIOSH 1988).

5.4.3.4 Effects of Biologic Agents

The skin can be damaged by a variety of microorganisms, including bacteria, fungi, viruses, and parasites. Herpes simplex is the most common dermatologic infection among dentists, physicians, and nurses. About 5% of all workers’ compensation claims for skin diseases in 1985 were the result of primary skin infections. Biologic agents can also cause secondary skin infections when skin has been damaged chemically or physically. Secondary infections are particularly likely if good personal hygiene is not practiced (NIOSH 1987a).

5.4.4 Standards and Recommendations

There are no OSHA standards or NIOSH recommendations that specifically address dermatitis.

5.4.5 Exposure Control Methods

Relatively simple precautions can considerably reduce skin hazards. Effective measures include work practices and engineering controls that limit solvent exposure, the use of personal protective equipment, substitution of less irritating chemicals, and the institution of a good hygiene program. A more complete discussion of methods for controlling dermatologic hazards is contained in A Proposed National Strategy for the Prevention of Occupational Dermatologic Conditions (ASPH/NIOSH 1988).