Workers encounter many noninfectious health hazards in hospitals, including chemical hazards, physical hazards, mutagens and teratogens, dermatologic hazards, and stress. The following subsections describe these hazards in terms of their location in the hospital, potential health effects, existing standards and recommendations for safe use, recommended environmental monitoring, existing exposure control methods, and recommended medical surveillance.
5.1 Chemical Hazards
5.1.1 Introduction
Chemicals may exert either acute or chronic effects on workers. The effects depend on (1) extent (concentration and duration) of exposure, (2) the route of exposure, and (3) the physical and chemical properties of the substance. The effects exerted by a substance may also be influenced by the presence of other chemicals and physical agents or by an individual’s use of tobacco, alcohol, or drugs. Basic principles of toxicology are reviewed in Doull et al. (1980).
5.1.1.1 Extent of Exposure
The exposure concentration of a substance is the mass per unit volume of air to which a worker is exposed. In the workplace, airborne concentrations are usually expressed in terms of milligrams of substance per cubic meter of air (mg/m3) or parts of substance per million parts of air (ppm). In the case of asbestos, concentration is expressed as fibers per cubic centimeter (f/cc) or fibers per cubic meter (f/m3) of air. The exposure dose is the amount of a substance that actually enters the body during the period of exposure. The substance continues to be present in the body until it is metabolized or eliminated. Although some chemicals are rapidly metabolized, others area not and may be excreted unchanged or stored in the fatty tissues (solvents), lungs (dusts and fibers), bone (lead and radium), or blood (soluble gases).
5.1.1.2 Route of Entry into the Body
Toxic substances can enter the body through several routes, including the intact skin, the respiratory system (inhalation), the mouth (inhalation and ingestion), the eyes, and by accidental needle punctures. Some substances can also damage the skin or eyes directly without being absorbed. Not all substances can enter the body through all routes. Inorganic lead, for example, can be inhaled or swallowed, but it does not penetrate the skin. (It should be noted that tetraethyl lead, a component of automotive gasolines, can be absorbed through the skin and therefore can contribute to the total absorbed dose.) Sometimes a chemical substance can enter through more than one route. Asbestos, for example, can be swallowed or inhaled, but the latter route appears to be more hazardous.
5.1.1.3 Physical and Chemical Properties
The physical properties of a chemical or physical agent include such characteristics as vapor pressure, solubility in water and organic solvents, boiling point, melting point, molecular weight, specific gravity, and morphology. chemical properties describe the reactivity of a substance with other chemicals.
5.1.1.4 Warning Properties
Some chemicals have characteristics that can be perceived by workers and can serve as a warning of the chemical’s presence. The most commonly discussed warning property is odor. Depending on a person’s ability to detect the odor of a substance, a chemical is considered to provide either good or poor warning of its presence. The lowest concentration at which the odor of a chemical can be detected is called the odor threshold. Some substances, such as asbestos, have no odor and therefore provide no warning of their presence. In many cases, the concentration of a chemical that can be detected by odor and the concentration that is capable of causing adverse effects are similar. For example, the odor threshold of ethylene oxide is about 700 ppm (Jay et al. 1982), a concentration that has been demonstrated to cause a variety of severe effects among exposed workers. In other cases, exposure to a chemical can cause olfactory fatigue that prevents a worker from continuing to smell the chemical. People cannot detect odors equally well. Thus some may be able to detect the odor of chlorine at a concentration of 0.02 ppm, and others cannot detect its presence until the concentration reaches 0.2 ppm (NIOSH 1976b). For these reasons, workers should not rely on their sense of smell to warn them of the presence of hazardous substances. Nevertheless, available information on odor thresholds has been included for the substances discussed here. A more complete discussion of odor as a warning property can be found in, Odor as an Aid to Chemical Safety: Odor Thresholds Compared with Threshold Limit Values and Volatilities for 214 Industrial Chemicals in Air and Water Dilution (Amoore and Hautala 1983) and Odor Threshold Determinations of 53 Odorant Chemicals (Leonardos et al. 1969).
5.1.1.5 Synergistic Effects of Various Hazards
Possible interactions may occur as a result of the multiple exposures that exist in a hospital environment. These interactions may involve (1) exposures to chemical and/or physical agents, (2) an individual’s use of tobacco, alcohol, or drugs, or (3) the physiological or psychological state of the worker. Limited data are available on interactions of physical and chemical agents; however two studies of other occupations have shown increased toxicity resulting from the synergistic effects of solvent mixtures (Murphy 1984; Struwe and Wennberg 1983). Information is also available on the interactions of chemical and physical agents and the consumption of tobacco, alcohol, or drugs (Bos et al. 1982; Robbin 1979; Hills and Venable 1982). NIOSH Current Intelligence Bulletin 31 includes a discussion of the adverse health effects of smoking in the work environment. To determine an exposure, it is imperative to consider other possible exposures or factors that might influence the results.
5.1.2 Asbestos
Asbestos refers to a group of impure magnesium silicate minerals that occur in fibrous form. Asbestos is defined to be chrysotile, crocidolite, and fibrous cummingtonite-grunerite including amosite, fibrous tremolite, fibrous actinolite, and fibrous anthophyllite (NIOSH 1980b). Because of the limitations of the analytical method, only fibers that are 5 micrometers or more in length and have a length-to-diameter ratio of 3:1 or greater are considered when determining a worker’s asbestos exposure (29 CFR* 1910.1001).
Because asbestos is an extremely hazardous material and compliance with all relevant aspects of the OSHA asbestos regulations must be assured, hospitals should develop a policy for working with asbestos. All workers who may have reason to work with this substance should receive training.
A hospital asbestos policy must outline specific OSHA requirements (29 CFR* 1910.1001) for the following:
5.1.2.1 Hazard Location
Hospitals use asbestos for many purposes, including the noncombustible, nonconducting, or chemically resistant materials required for fireproof clothing, curtains, and roofing. Before the early 1970’s, asbestos was used as insulation throughout most buildings (including hospitals). Significant asbestos exposures can occur when insulation in old buildings is removed during renovation. Maintenance personnel in most hospitals do not know and often are not trained in the proper methods of performing repairs on systems that contain asbestos. They frequently perform spot repairs without protecting themselves, patients, or staff from exposure. Asbestos is also used to make heat-resistant protective gloves for central supply and laboratories. With time, these gloves may become worn and disintegrate, releasing fibers into the air.
5.1.2.2 Potential Health Effects
Asbestos causes asbestosis (a fibrosis or scarring of the lung tissue) and cancer. These diseases may develop 15 to 30 years after the first exposure.
Asbestosis belongs to the group of pulmonary diseases called pneumoconioses; these include coal workers’ pneumoconiosis (often called black lung disease) among coal workers and silicosis among workers with prolonged exposure to sand blasting or other operations in which silica-containing rock is crushed, drilled, or used. Pneumoconiosis is characterized by restriction of lung function, which eventually increases the load on the circulatory system so that the fully developed disease usually involves heart failure as well. The only hospital workers most likely to encounter enough asbestos to produce asbestosis are engineers who work in furnace rooms where boilers are lined with asbestos, and maintenance workers who frequently repair old piping or do minor renovation. These workers must take special care to protect themselves and to ensure that asbestos is not spread throughout the facility when they perform tasks involving this substance.
Inhaling asbestos, even in small amounts, may result in lung cancer, gastrointestinal cancer, or mesothelioma (a cancer of the lung and abdomen lining). An association has also been suggested between the ingestion of asbestos and the development of gastrointestinal cancer, but no studies have yet confirmed this Persons with less than a month of exposure have been known to develop mesotheliomas 20 or 30 years later. Because there is no know safe level of asbestos exposure, any hospital worker who is exposed to moderate or high concentrations of asbestos for even a relatively short time may be at increased risk of developing asbestos-related diseases.
All asbestos-exposed workers have a higher risk of lung cancer than nonexposed workers, but exposed workers who smoke cigarettes have a markedly greater risk of lung cancer than nonsmoking exposed workers (29 CFR 1910.1001).
5.1.2.3 Standards and Recommendations
The current OSHA PEL for asbestos is an 8-hour TWA concentration of 0.2 f/cc (200,000 f/m3) for fibers that are 5 micrometers or longer and that have a length-to-diameter ratio of 3:1 (29 CFR 1910.1001). The asbestos standard is very detailed and has specific requirements for training, labeling, protective equipment, medical surveillance, and environmental monitoring. Questions regarding the implementation of the standard should be referred to the State or Federal OSHA program, which has a consultation service. The NIOSH REL for asbestos (fibers longer than 5 micrometers with a length-to-diameter ratio of 3:1 or greater) is an 8-hr TWA concentration of 100000 f/m3 (0.1 f/cc) (NIOSH 1984b).
5.1.2.4 Environmental Monitoring
Sampling should be conducted in a manner and on a schedule that will provide an accurate depiction of job-specific asbestos exposures. All analyses should be done by laboratories accredited by the American Industrial Hygiene Association (AIHA). The minimum schedule for monitoring is established by OSHA regulation ((29 CFR 1910.1001).
5.1.2.5 Exposure Control Methods
5.1.2.5.1 Removal and encapsulation
Whenever asbestos fibers are exposed, they present a hazard that can be eliminated by removing or encapsulating (covering) them so that they will not be released. Asbestos must only be removed by fully trained personnel using methods and protective equipment mandated by OSHA (29 CFR 1910.1001).
5.1.2.5.2 Protective equipment
Complete physical covering and a NIOSH/MSHA-certified, positive-pressure, air-supplied respirator are required for any worker exposed to asbestos. The OSHA asbestos standard should be consulted along with the NIOSH/EPA document entitled A Guide to Respiratory Protection for the Asbestos Abatement Industry (NIOSH/EPA 1986).
5.1.2.5.3 Work practices
Only workers fully trained in asbestos handling should be allowed in areas where asbestos is exposed. The work practices appropriate for handling asbestos are set out in detail in the OSHA regulation (29 CFR 1910.1001).
5.1.3 Chemical Disinfectants
Because of the variety of needs for disinfectants within the hospital, a number of different substances are used. The most important are:
5.1.3.1 Isopropyl Alcohol
5.1.3.1.1 Hazard location
Isopropyl alcohol is a widely used antiseptic and disinfectant; it is used mostly to disinfect thermometers, needles, anesthesia equipment, and various other instruments.
5.1.3.1.2 Potential health effects
The odor of isopropyl alcohol may be detected at concentrations of 40 to 200 ppm (NIOSH 1976a). Exposure to isopropyl alcohol can cause irritation of the eyes and mucous membranes. Contact with the liquid may also cause skin rashes.
5.1.3.1.3 Standards and recommendations
The OSHA PEL for isopropyl alcohol is 400 ppm (980 mg/m3) as an 8-hr TWA (29 CFR 1910.1000, Table Z-1). The NIOSH REL for isopropyl alcohol is 400 ppm (984 mg/m3) for up to a 10-hr TWA with a ceiling of 800 ppm (1,968 mg/m3) for 15 min (NIOSH 1976a).
5.1.3.1.4 Exposure control methods
Workers should be provided with and required to use appropriate protective clothing (see Section 2.3.5) such as gloves and face shields to prevent repeated or prolonged skin contact with isopropyl alcohol. Splash-proof safety goggles should also be provided and required for use where isopropyl alcohol may contact the eyes.
Any clothing that becomes wet with isopropyl alcohol should be removed immediately and reworn only after the compound has been removed. clothing wet with isopropyl alcohol should be stored in closed containers until it can be discarded or cleaned. The worker who is laundering or cleaning such clothes should be informed of isopropyl alcohol’s hazardous properties.
Skin that becomes wet with liquid isopropyl alcohol should be promptly washed or showered.
Adequate exhaust ventilation must be supplied in the hospital to remove isopropyl alcohol vapor in the work area.
5.1.3.2 Sodium Hypochlorite (Chlorine)
Chlorine can be generated from solutions of sodium hypochlorite. Chlorine is effective against bacteria and viruses, and it can destroy some spores, depending on the concentration.
5.1.3.2.1 Hazard location
Chlorine is used for disinfecting water tanks, bathtubs, toilets, and bathrooms; it is also used as a bleach for laundries, a sanitizer for dishwashing, and a disinfectant for floors. Chlorine-containing cleaning materials should never be mixed with ammonia or ammonia-containing materials because the reaction may produce a toxic gas.
5.1.3.2.2 Potential health effects
Chlorine is released slowly from cleaning and bleaching solutions as they are used. Repeated exposure to chlorine may cause a runny nose, coughing, wheezing, and other respiratory problems (NIOSH 1976b). Mild irritation of the mucous membranes can occur at exposure concentrations of 0.5 ppm (ACGIH 1986).
5.1.3.2.3 Standards and recommendations
The OSHA PEL for chlorine is a ceiling of 1 ppm (3 mg/m3) (29 CFR 1910.1000, Table Z-1). The NIOSH REL is a ceiling of 0.5 ppm for 15 min (NIOSH 1976b). Chlorine has an odor threshold between 0.02 and 0.2 ppm, but since the sense of smell is dulled by continued chlorine exposure, odor does not provide adequate warning (NIOSH 1976b).
The ACGIH recommends a TLV of 1 ppm (3.0 mg/m3) as an 8-hr TWA and a short-term exposure limit (STEL) of 3 ppm ( 9 mg/m3) but has published a notice of intended change to a TLV of 0.5 ppm (1.5 mg/m3) as an 8-hr TWA and a STEL of 1 ppm (3 mg/m3) (ACGIH 1987).
5.1.3.2.4 Exposure control methods
Workers should be provided with and required to use splash-proof safety goggles where there is any possibility that chlorine-containing solutions may contact the eyes. To prevent any possibility of skin contact with chlorine-containing liquids, workers should be provided with and required to use appropriate personal protective equipment (see Section 2.3.5) such as gloves, face shields, and respirators (see Section 2.3.5.6) as necessary. Nonimpervious clothing that becomes contaminated with chlorine-containing solutions should be removed immediately and reworn only after the chlorine-containing solution is removed from the clothing. Skin that becomes contaminated with chlorine should be immediately washed to remove any chlorine. Additional control measures for chlorine include process enclosure and good exhaust ventilation.
5.1.3.3 Iodine
Iodine is a general disinfectant; it can be mixed with alcohol for use as a skin antiseptic or with other substances for general disinfecting purposes.
5.1.3.3.1 Hazard location
Iodine can be found throughout the hospital.
5.1.3.3.2 Potential health effects
Symptoms of iodine exposure include irritation of the eyes and mucous membranes, headaches, and breathing difficulties (ACGIH 1986). Crystalline iodine or strong solutions of iodine may cause severe skin irritation: it is not easily removed from the skin and may cause burns.
5.1.3.3.3 Standards and recommendations
The OSHA PEL for iodine is a ceiling of 0.1 ppm (1.0 mg/m3) (29 CFR 1910.1001, Table Z-1). The ACGIH recommends a TLV of 0.1 ppm (1.0 mg/m3) as a ceiling (ACGIH 1987). NIOSH has no REL for iodine.
5.1.3.3.4 Exposure control methods
To prevent skin contact with solids or liquids containing iodine, workers should be provided with and required to use personal protective equipment such as gloves, face shields, and any other appropriate protective clothing deemed necessary (see Section 2.3.5).
If there is any possibility that clothing ahs been contaminated with solid iodine or liquids containing iodine, a worker should change into uncontaminated clothing before leaving the work area. Clothing contaminated with iodine should be stored in closed containers until provision is made to remove the iodine. The person laundering or cleaning such clothes should be informed of iodine’s hazardous properties.
Skin that becomes contaminated with solids or liquids containing iodine should be immediately washed with soap or mild detergent and rinsed with water. Workers who handle solid iodine or liquids containing iodine should wash their hands thoroughly with soap or mild detergent and water before eating, smoking, or using toilet facilities.
5.1.3.4 Phenolics
Phenolics were among the first disinfectants used in hospitals. Certain detergent disinfectants belong to the phenol group, including phenol, para-tertiary butylphenol (ptBP), and para-tertiary amylphenol (ptAP). They are generally used for a wide range of bacteria, but they are not effective against spores.
5.1.3.4.1 Hazard location
Phenolics are widely used on floors, walls, furnishings, glassware, and instruments.
5.1.3.4.2 Potential health effects
Phenol may be detected by odor at a concentration of about 0.05 ppm. Serious health effects may follow exposure to phenol through skin adsorption, inhalation, or ingestion. These effects may include local tissue irritation and necrosis, severe burns of the eyes and skin, irregular pulse, stertorous breathing (harsh snoring or gasping sound), darkened urine, convulsions, coma, collapse, and death (NIOSH 1976d). Both ptBP and ptAP have caused hospital worker to experience loss of skin pigment that was not reversed one year after use of the compounds was discontinued (Kahn 1970).
5.1.3.4.3 Standards and recommendations
The OSHA PEL for phenol is 5 ppm (19 mg/m3) as an 8-hr TWA (Skin) (29 CFR 1910.1000, Table Z-1). The NIOSH REL for phenol is 20 mg/m3 (5.2 ppm) for up to a 10-hr TWA with a 15-min ceiling of 60 mg/m3 (15.6 ppm) (NIOSH 1976d). Neither OSHA nor NIOSH has established exposure limits for ptBP or ptAP.
5.1.3.4.4 Exposure control methods
When working with phenol, workers should be provided with and required to use protective clothing (see Section 2.3.5), gloves, face shields, splash-proof safety goggles, and other appropriate protective clothing necessary to prevent any possibility of skin or eye contact with solid or liquid phenol or liquids containing phenol.
If there is any possibility that the clothing has been contaminated with phenol, a worker should change into uncontaminated clothing before leaving the work area and the suspect clothing should be stored in closed containers until it can be discarded or until provision is made for removal of the phenol. The worker laundering or cleaning such clothes should be informed of phenol’s hazardous properties.
Skin that becomes contaminated with phenol should be immediately washed with soap or mild detergent and rinsed with water. Eating and smoking should not be permitted in areas where solid or liquid phenol or liquids containing phenol are handled, processed, or stored. Workers who handle solid or liquid phenol or liquids containing phenol should wash their hands thoroughly with soap or mild detergent and water before eating, smoking, or using toilet facilities.
Additional measures to control phenol exposure include process enclosure, local exhaust ventilation, and personal protective equipment.
5.1.3.5 Quaternary Ammonium Compounds
5.1.3.5.1 Hazard location
Quaternary ammonium compounds are widely used as disinfectants in hospitals, and they have the major disadvantage of being ineffective against tuberculosis and gram-negative bacteria. Quaternary ammonium compounds area most likely to be encountered by workers in central supply, housekeeping, patient, and surgical services areas. The detergent benzalkonium chloride is the most widely used quaternary ammonium compound and is found in the following commercial products (Cohen 1987):
5.1.3.5.2 Potential health effects
Quaternary ammonium compounds can cause contact dermatitis, but they tend to be less irritating to hands than other substances. They can also cause nasal irritation.
5.1.3.5.3 Standards and recommendations
No OSHA PEL, NIOSH REL, or ACGIH TLV exists for quaternary ammonium compounds.
5.1.3.6 Glutaraldehyde
Although glutaradelhyde is available in 50%, 25%, 10% and 2% solutions, most hospitals use 2% Glutaraldehyde solutions buffered to pH 7.5 to 8.5 before use. Glutaraldehyde solutions also contain surfactants to promote wetting and rinsing of surfaces, sodium nitrite to inhibit corrosion, peppermint oil as an odorant, and FD&C yellow and blue dyes to indicate activation of the solution (NIOSH 1983b). One disadvantage of buffered glutaraldehyde solutions is that they are stable for less than 2 weeks, so solutions must be dated and made as needed (Gorman et al. 1980). Another disadvantage is that at 20 degrees C (68°F), a 50% solution of glutaraldehyde has a vapor pressure of 0.015 mmHg (ACGIH 1986) and thus can generate an atmosphere that contains as much as 20 ppm of glutaraldehyde. This concentration is well above that shown to cause adverse health effects in animals and humans.
5.1.3.6.1 Hazard location
Glutaraldehyde is a newer disinfectant that is especially effective for cold sterilization of instruments; it has recently been used as a substitute for formaldehyde during embalming. Glutaraldehyde has been used in pulmonary physiology units, at nurses’ stations, and in research laboratories. As a disinfectant, glutaraldehyde has been used to clean sputum mouthpieces, suction bottles and tubing, and equipment used for ear, nose, and throat treatment (NIOSH 1983b).
5.1.3.6.2 Potential health effects
Glutaraldehyde may be absorbed into the body by inhalation, ingestion, and skin contact. Extensive skin contact may cause allergic eczema and may also affect the nervous system. Glutaraldehyde has an odor threshold of about 0.04 ppm, is highly toxic, and is irritating to the skin and mucous membranes at concentrations of about 0.3 ppm (1.05 mg/m3) (ACGIH 1986). In a study of 541 members of a hospital cleaning department, 39.1% of the workers had skin disease during their employment. In 21% of the workers, contact dermatitis was attributed to the use of glutaraldehyde, formaldehyde, and chloramine (Hansen, 1983).
A NIOSH investigation (NIOSH 1983b) determined that airborne glutaraldehyde concentrations of 0.4 ppm (1.5 mg/m3) were responsible for symptoms of irritation in 9 of 11 (82%) exposed workers. Eye, throat, and lung irritation were reported among 45% of the workers. Other symptoms, including cough, chest tightness, headache, skin irritation, and asthma-like symptoms, were also reported.
Glutaraldehyde exposure has been associated with fetotoxicity in mice, DNA damage in chickens and hamsters, and mutagenicity in microorganisms (NIOSH 1985).
5.1.3.6.3 Standards and recommendations
The ACGIH recommended ceiling limit for glutaraldehyde is 0.2 ppm (0.8 mg/m3) (ACGIH 1986). OSHA does not have a PEL for glutaraldehyde, and NIOSH and no REL.
5.1.3.6.4 Exposure control methods
Workers should avoid breathing glutaraldehyde vapors. They should also be provided with and required to use splash-proof safety goggles where there is any possibility of contaminating the eyes with glutaraldehyde. To prevent any possibility of skin contact, workers should be provided with and required to use protective clothing (See Section 2.3.5). If clothing becomes contaminated with glutaraldehyde, it should be promptly removed and not reworn until the glutaraldehyde has been removed. The worker who is laundering or cleaning such clothes should be informed of glutaraldehyde hazardous properties. Skin that becomes contaminated with glutaraldehyde should be washed immediately or showered.
5.1.3.7 Formaldehyde
formaldehyde is used for cold sterilization of various instruments and as an embalming agent. This compound is fully discussed later in this Section (5.1.6).
