Disclaimer: These guidelines were developed under contract using generally accepted secondary sources. The protocol used by the contractor for surveying these data sources was developed by the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA), and the Department of Energy (DOE). The information contained in these guidelines is intended for reference purposes only. None of the agencies have conducted a comprehensive check of the information and data contained in these sources. It provides a summary of information about chemicals that workers may be exposed to in their workplaces. The secondary sources used for supplements 111 and 1V were published before 1992 and 1993, respectively, and for the remainder of the guidelines the secondary sources used were published before September 1996. This information may be superseded by new developments in the field of industrial hygiene. Therefore readers are advised to determine whether new information is available.

OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR DIBUTYL PHTHALATE

INTRODUCTION

This guideline summarizes pertinent information about dibutyl phthalate for workers and employers as well as for physicians, industrial hygienists, and other occupational safety and health professionals who may need such information to conduct effective occupational safety and health programs. Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new information is available.

SUBSTANCE IDENTIFICATION

* Formula

C(16)H(22)O(4)

* Structure

(For Structure, see paper copy)

* Synonyms

DBP; dibutyl 1,2-benzenedicarboxylate; phthalic acid dibutyl ester;

1,2-benzenedicarboxylic acid dibutyl ester; n-butyl phthalate

* Identifiers

1. CAS No.: 84-74-2

2. RTECS No.: TI0875000

3. Specific DOT UN: None.

4. Specific DOT label: None.

* Appearance and odor

Dibutyl phthalate is a colorless, oily liquid with a very weak, aromatic odor.

CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

1. Molecular weight: 278.3

2. Boiling point (at 760 mm Hg): 340 degrees C (644 degrees F)

3. Specific gravity (water = 1): 1.05 at 20 degrees C (68 degrees F)

4. Vapor density: 9.6

5. Melting point: -35 degrees C (-31 degrees F)

6. Vapor pressure at 20 degrees C (68 degrees F): Less than 0.01 mm Hg

7. Solubility: Insoluble in water; soluble in alcohol, ether, and benzene.

8. Evaporation rate: Data not available.

* Reactivity

1. Conditions contributing to instability: Heat or flame.

2. Incompatibilities: Contact between dibutyl phthalate and nitrates, strong oxidizers, strong alkalies, strong acids, and chlorine should be avoided.

3. Hazardous decomposition products: Toxic gases such as carbon monoxide may be released in a fire involving dibutyl phthalate.

4. Special precautions: None reported.

* Flammability

The National Fire Protection Association has assigned a flammability rating of 1 (slight fire hazard) to dibutyl phthalate.

1. Flash point: 157 degrees C (315 degrees F) (closed cup)

2. Autoignition temperature: 402 degrees C (756 degrees F)

3. Flammable limits in air (percent by volume): Lower, 0.5%; upper, 2.5%

4. Extinguishant: Use water spray, dry chemical, carbon dioxide, or foam to fight fires involving dibutyl phthalate. Water or foam may cause frothing.

Fires involving dibutyl phthalate should be fought upwind from the maximum distance possible. Isolate the hazard area and deny access to unnecessary personnel. Cool fire-exposed containers with water spray. Firefighters should wear a full set of protective clothing and self-contained breathing apparatus when fighting fires involving dibutyl phthalate.

EXPOSURE LIMITS

* OSHA PEL

The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for dibutyl phthalate is 5.0 milligrams per cubic meter (mg/m(3)) of air as an 8-hour time-weighted average (TWA) concentration [29 CFR 1910.1000, Table Z-1].

* NIOSH REL

The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for dibutyl phthalate of 5.0 mg/m(3) as a TWA for up to a 10-hour workday and a 40-hour workweek [NIOSH 1992].

* ACGIH TLV

The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned dibutyl phthalate a threshold limit value (TLV) of 5.0 mg/m(3) as a TWA for a normal 8-hour workday and a 40-hour workweek [ACGIH 1994, p. 18].

* Rationale for Limits

The NIOSH limit is based on the risk of irritation to the eyes and respiratory tract from the heated substance [NIOSH 1992].

The ACGIH limit is based on the low order of toxicity associated with exposure to dibutyl phthalate [ACGIH 1991, p. 401].

HEALTH HAZARD INFORMATION

* Routes of Exposure

Exposure to dibutyl phthalate can occur through inhalation, ingestion, and eye or skin contact [Sittig 1991].

* Summary of toxicology

1. Effects on Animals: DBP is a mild eye and upper respiratory tract irritant in experimental animals. The acute oral LD(50) for dibutyl phthalate (DBP) in rats is between 8 and 10 g/kg. A 2-hour exposure of mice to an aerosol of DBP at 250 mg/m(3) resulted in eye and upper respiratory tract irritation. Higher levels of exposure caused labored breathing, ataxia, weakness, convulsions and death from respiratory paralysis. The LC(50) in mice was 25,000 mg/m(3) for an undefined exposure duration. Rats exposed to concentrations as low as 0.5 mg/m(3) of DBP mist for 6 hours/day for 6 months had smaller weight gains; and greater brain and lung weights than controls. In a 1.5 year gavage study, rats receiving a solution of DBP in oil at 1 ml/kg of body weight had no adverse changes in hematology, pathology of organ tissues, and organ weights. Several chronic carcinogenicity studies have demonstrated that DBP is not an animal carcinogen. Reduced testes weights and cellular injury were seen in mice and guinea pigs fed 2 g/kg/day for 10 days. In a study of pregnant female rats administered doses of DBP at 1/10, 1/5, and 1/3 the acute LD(50), significant dose-related fetal deaths and abnormalities occurred [Hathaway et al. 1991]. A 2-hour exposure of mice to 250 mg/m(3) of DBP aerosol induced eye irritation; however, undiluted DBP instilled in rabbit eyes caused no observable irritation [Hathaway et al. 1991]. Rats fed lethal doses of DBP exhibited edema of the eyelids and conjunctivitis [Grant 1986].

2. Effects on Humans: The acute toxicity of dibutyl phthalate is low. A worker who reportedly swallowed 10 grams of DBP became nauseated, dizzy, and developed photophobia, tearing, conjunctivitis, keratitis with loss of corneal epithelium, and signs of transitory toxic nephritis as evidenced by red and white blood cells and oxalate crystals in the urine. He recovered promptly and completely. There is, however, some doubt as to whether DBP was the substance ingested [Hathaway et al. 1991; Grant 1986]. Fifty-three volunteers dermally tested with 5 percent DBP solution (48 hour closed patch test) showed no reactions. Responses to cosmetic formulations containing up to 9 percent DBP ranged from nonirritating to slightly irritating in various patch test procedures. Sensitization and photosensitization did not occur [Hathaway et al. 1991]. In a study of 147 Russian workers exposed to several phthalate plasticizers in the artificial leather industry, significant adverse health effects were reported. The duration of employment was from 0.5 to 19 years, and the ambient air concentrations for the mixed phthalate esters varied from 1.7 to 66 mg/m(3). Beginning in the 6th to 7th year of work, pain, numbness, and spasms of the arms and legs were reported. This was followed by weakness of the extremities. Extensive neurological studies showed a 32 percent rate of polyneuritis among workers in the group studies [ACGIH 1991]. Women workers exposed to phthalates have been reported to have more menstrual disorders, miscarriages, reduced gestation and delivery rates than controls. Contact of the surface of the eye with DBP causes pain and tearing, but no permanent eye damage [Grant 1986].

* Signs and symptoms of exposure

1. Acute exposure: Splashing liquid DBP in the eyes causes immediate severe pain and profuse tearing. Exposure to dibutyl phthalate mist can cause nose and upper respiratory tract irritation. Reported effects after ingestion are nausea, dizziness, sensitivity to light, redness of the eyes, and transient kidney inflammation [Sittig 1991; Hathaway et al. 1991; Grant 1986].

2. Chronic exposure: Symptoms of chronic exposure to mixtures of dibutyl phthalate and other esters include pain, numbness, and spasms in the upper and lower extremities, followed by weakness of the upper and lower extremities. Polyneuritis may also occur [ACGIH 1991].

EMERGENCY MEDICAL PROCEDURES

* Emergency medical procedures: [NIOSH to supply]

5. Rescue: Remove an incapacitated worker from further exposure and implement appropriate emergency procedures (e.g., those listed on the Material Safety Data Sheet required by OSHA's Hazard Communication Standard [29 CFR 1910.1200]). All workers should be familiar with emergency procedures, the location and proper use of emergency equipment, and methods of protecting themselves during rescue operations.

EXPOSURE SOURCES AND CONTROL METHODS

The following operations may involve dibutyl phthalate and lead to worker exposures to this substance:

* The manufacture and transportation of dibutyl phthalate

* Liberated during application of polyvinyl acetate surface coating by spraying, dipping, or crushing; liberated during spray application of polyester and epoxy resins; use as a resin solvent

* Used during spray application of nitrocellulose lacquer surface coatings, including paper coatings

* Liberated during brush application of nitrocellulose surface coatings; during manufacture of polyester and epoxy resins; used as a plasticizer in nitrocellulose lacquers, elastomers, explosives, nail polish, and solid rocket propellants; use in plasticizing cellulose esters and vinyl acetate emulsion systems; in the manufacture of cellophane, lacquers, dyes, and leather; use as component of polyvinyl chloride plastic for carpet backing

* Used as a solvent for perfume oils and as a perfume fixative; as a textile lubricating agent, as an insecticide and insect repellant for textiles; used in the manufacture of safety glass and printing inks; used as manometer fluid

* Use in the measurement of void volume for carbon blacks; as a desensitizing agent to make nitroglycerine stable for transport

Methods that are effective in controlling worker exposures to dibutyl phthalate, depending on the feasibility of implementation, are as follows:

* Process enclosure
* Local exhaust ventilation
* General dilution ventilation
* Personal protective equipment

Workers responding to a release or potential release of a hazardous substance must be protected as required by paragraph (q) of OSHA's Hazardous Waste Operations and Emergency Response Standard [29 CFR 1910.120].

Good sources of information about control methods are as follows:

1. ACGIH [1992]. Industrial ventilation--a manual of recommended practice. 21st ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

2. Burton DJ [1986]. Industrial ventilation--a self study companion. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

3. Alden JL, Kane JM [1982]. Design of industrial ventilation systems. New York, NY: Industrial Press, Inc.

4. Wadden RA, Scheff PA [1987]. Engineering design for control of workplace hazards. New York, NY: McGraw-Hill.

5. Plog BA [1988]. Fundamentals of industrial hygiene. Chicago, IL: National Safety Council.

MEDICAL SURVEILLANCE

OSHA is currently developing requirements for medical surveillance. When these requirements are promulgated, readers should refer to them for additional information and to determine whether employers whose employees are exposed to dibutyl phthalate are required to implement medical surveillance procedures.

* Medical Screening

Workers who may be exposed to chemical hazards should be monitored in a systematic program of medical surveillance that is intended to prevent occupational injury and disease. The program should include education of employers and workers about work-related hazards, early detection of adverse health effects, and referral of workers for diagnosis and treatment. The occurrence of disease or other work-related adverse health effects should prompt immediate evaluation of primary preventive measures (e.g., industrial hygiene monitoring, engineering controls, and personal protective equipment). A medical surveillance program is intended to supplement, not replace, such measures. To detect and control work-related health effects, medical evaluations should be performed (1) before job placement, (2) periodically during the term of employment, and (3) at the time of job transfer or termination.

* Preplacement medical evaluation

Before a worker is placed in a job with a potential for exposure to dibutyl phthalate, a licensed health care professional should evaluate and document the worker's baseline health status with thorough medical, environmental, and occupational histories, a physical examination, and physiologic and laboratory tests appropriate for the anticipated occupational risks. These should concentrate on the function and integrity of the respiratory and gastrointestinal systems [Sittig 1991, p. 554]. Medical surveillance for respiratory disease should be conducted using the principles and methods recommended by the American Thoracic Society [ATS 1987].

A preplacement medical evaluation is recommended to assess medical conditions that may be aggravated or may result in increased risk when a worker is exposed to dibutyl phthalate at or below the prescribed exposure limit. The health care professional should consider the probable frequency, intensity, and duration of exposure as well as the nature and degree of any applicable medical condition. Such conditions (which should not be regarded as absolute contraindications to job placement) include a history and other findings consistent with diseases of the respiratory or gastrointestinal systems.

* Periodic medical evaluations

Occupational health interviews and physical examinations should be performed at regular intervals during the employment period, as mandated by any applicable Federal, State, or local standard. Where no standard exists and the hazard is minimal, evaluations should be conducted every 3 to 5 years or as frequently as recommended by an experienced occupational health physician. Additional examinations may be necessary if a worker develops symptoms attributable to dibutyl phthalate exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of dibutyl phthalate on the respiratory or gastrointestinal systems. Current health status should be compared with the baseline health status of the individual worker or with expected values for a suitable reference population.

* Termination medical evaluations

The medical, environmental, and occupational history interviews, the physical examination, and selected physiologic or laboratory tests that were conducted at the time of placement should be repeated at the time of job transfer or termination to determine the worker's medical status at the end of his or her employment. Any changes in the worker's health status should be compared with those expected for a suitable reference population.

* Biological monitoring

Biological monitoring involves sampling and analyzing body tissues or fluids to provide an index of exposure to a toxic substance or metabolite. No biological monitoring test acceptable for routine use has yet been developed for dibutyl phthalate.

WORKPLACE MONITORING AND MEASUREMENT

Determination of a worker's exposure to airborne dibutyl phthalate is made using an OSHA Versatile Sampler (OVS-Tenax) - 13 mm Tenax tube (140/70 mg sections) with a glass fiber filter enclosed. Samples are collected at a maximum flow rate of 1.0 liter/minute until a maximum collection volume of 240 liters is reached. The sample is then treated with toluene. Analysis is conducted by gas chromatography using a flame ionization detector (GC/FID). This method (OSHA # 104) is described in the OSHA Computerized Information System [OSHA 1994] and is fully validated. NIOSH Method No. 5020 (dibutyl phthalate) can also be used to determine a worker's exposure to airborne dibutyl phthalate [NIOSH 1994b].

PERSONAL HYGIENE PROCEDURES

If dibutyl phthalate contacts the skin, workers should flush the affected areas immediately with plenty of water, followed by washing with soap and water.

Clothing contaminated with dibutyl phthalate should be removed immediately, and provisions should be made for the safe removal of the chemical from the clothing. Persons laundering the clothes should be informed of the hazardous properties of dibutyl phthalate, particularly its potential for causing irritation.

A worker who handles dibutyl phthalate should thoroughly wash hands, forearms, and face with soap and water before eating, using tobacco products, using toilet facilities, applying cosmetics, or taking medication.

Workers should not eat, drink, use tobacco products, apply cosmetics, or take medication in areas where dibutyl phthalate or a solution containing dibutyl phthalate is handled, processed, or stored.

STORAGE

Dibutyl phthalate should be stored in a cool, dry, well-ventilated area in tightly sealed containers that are labeled in accordance with OSHA's Hazard Communication Standard [29 CFR 1910.1200]. Containers of dibutyl phthalate should be protected from physical damage and ignition sources, and should be stored separately from nitrates, strong oxidizers, strong alkalies, strong acids, and chlorine.

SPILLS AND LEAKS

In the event of a spill or leak involving dibutyl phthalate, persons not wearing protective equipment and clothing should be restricted from contaminated areas until cleanup has been completed. The following steps should be undertaken following a spill or leak:

1. Notify safety personnel.

2. Remove all sources of heat and ignition.

3. Ventilate potentially explosive atmospheres.

4. Do not touch the spilled material; stop the leak if it is possible to do so without risk.

5. Use non-sparking tools.

6. Water spray may be used to reduce vapors; prevent flushing waste to a sewer or watercourse.

7. For small spills, take up with sand or other noncombustible absorbent material and place into closed containers for later disposal.

8. For large spills, build dikes far ahead of the spill to contain the dibutyl phthalate for later reclamation or disposal.

SPECIAL REQUIREMENTS

U.S. Environmental Protection Agency (EPA) requirements for emergency planning, reportable quantities of hazardous releases, community right-to-know, and hazardous waste management may change over time. Users are therefore advised to determine periodically whether new information is available.

* Emergency planning requirements

Dibutyl phthalate is not subject to EPA emergency planning requirements under the Superfund Amendments and Reauthorization Act (SARA) (Title III) in 42 USC 11022.

* Reportable quantity requirements for hazardous releases

A hazardous substance release is defined by EPA as any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment (including the abandonment or discarding of contaminated containers) of hazardous substances. In the event of a release that is above the reportable quantity for that chemical, employers are required to notify the proper Federal, State, and local authorities [40 CFR 355.40].

The reportable quantity of dibutyl phthalate is 10 pounds. If an amount equal to or greater than this quantity is released within a 24-hour period in a manner that will expose persons outside the facility, employers are required to do the following:

- Notify the National Response Center immediately at (800) 424-8802 or at (202) 426-2675 in Washington, D.C. [40 CFR 302.6].

* Community right-to-know requirements

Employers who own or operate facilities in SIC codes 20 to 39 that employ 10 or more workers and that manufacture 25,000 pounds or more of dibutyl phthalate per calendar year or otherwise use 10,000 pounds or more of dibutyl phthalate per calendar year are required by EPA [40 CFR Part 372.30] to submit a Toxic Chemical Release Inventory form (Form R) to EPA reporting the amount of dibutyl phthalate emitted or released from their facility annually.

* Hazardous waste management requirements

EPA considers a waste to be hazardous if it exhibits any of the following characteristics: ignitability, corrosivity, reactivity, or toxicity as defined in 40 CFR 261.21-261.24. Under the Resource Conservation and Recovery Act (RCRA) [40 USC 6901 et seq.], EPA has specifically listed many chemical wastes as hazardous. Dibutyl phthalate is listed as a hazardous waste under RCRA and has been assigned EPA Hazardous Waste No. U069. It is approved for land disposal after treatment and only if the concentration of dibutyl phthalate in the waste or treatment residual does not exceed 28 mg/kg.

Providing detailed information about the removal and disposal of specific chemicals is beyond the scope of this guideline. The U.S. Department of Transportation, EPA, and State and local regulations should be followed to ensure that removal, transport, and disposal of this substance are conducted in accordance with existing regulations. To be certain that chemical waste disposal meets EPA regulatory requirements, employers should address any questions to the RCRA hotline at (703) 412-9810 (in the Washington, D.C. area) or toll-free at (800) 424-9346 (outside Washington, D.C.). In addition, relevant State and local authorities should be contacted for information on any requirements they may have for the waste removal and disposal of this substance.

RESPIRATORY PROTECTION

* Conditions for respirator use

Good industrial hygiene practice requires that engineering controls be used where feasible to reduce workplace concentrations of hazardous materials to the prescribed exposure limit. However, some situations may require the use of respirators to control exposure. Respirators must be worn if the ambient concentration of dibutyl phthalate exceeds prescribed exposure limits. Respirators may be used (1) before engineering controls have been installed, (2) during work operations such as maintenance or repair activities that involve unknown exposures, (3) during operations that require entry into tanks or closed vessels, and (4) during emergencies. Workers should only use respirators that have been approved by NIOSH and the Mine Safety and Health Administration (MSHA).

* Respiratory protection program

Employers should institute a complete respiratory protection program that, at a minimum, complies with the requirements of OSHA's Respiratory Protection Standard [29 CFR 1910.134]. Such a program must include respirator selection, an evaluation of the worker's ability to perform the work while wearing a respirator, the regular training of personnel, respirator fit testing, periodic workplace monitoring, and regular respirator maintenance, inspection, and cleaning. The implementation of an adequate respiratory protection program (including selection of the correct respirator) requires that a knowledgeable person be in charge of the program and that the program be evaluated regularly. For additional information on the selection and use of respirators and on the medical screening of respirator users, consult the latest edition of the NIOSH Respirator Decision Logic [NIOSH 1987b] and the NIOSH Guide to Industrial Respiratory Protection [NIOSH 1987a].

PERSONAL PROTECTIVE EQUIPMENT

Workers should use appropriate personal protective clothing and equipment that must be carefully selected, used, and maintained to be effective in preventing skin contact with dibutyl phthalate. The selection of the appropriate personal protective equipment (PPE) (e.g., gloves, sleeves, encapsulating suits) should be based on the extent of the worker's potential exposure to dibutyl phthalate. The resistance of various materials to permeation by dibutyl phthalate is shown below:

(*) Not recommended, degradation may occur

To evaluate the use of these PPE materials with dibutyl phthalate, users should consult the best available performance data and manufacturers' recommendations. Significant differences have been demonstrated in the chemical resistance of generically similar PPE materials (e.g., butyl) produced by different manufacturers. In addition, the chemical resistance of a mixture may be significantly different from that of any of its neat components.

Any chemical-resistant clothing that is used should be periodically evaluated to determine its effectiveness in preventing dermal contact. Safety showers and eye wash stations should be located close to operations that involve dibutyl phthalate.

Splash-proof chemical safety goggles or face shields (20 to 30 cm long, minimum) should be worn during any operation in which a solvent, caustic, or other toxic substance may be splashed into the eyes.

In addition to the possible need for wearing protective outer apparel (e.g., aprons, encapsulating suits), workers should wear work uniforms, coveralls, or similar full-body coverings that are laundered each day. Employers should provide lockers or other closed areas to store work and street clothing separately. Employers should collect work clothing at the end of each work shift and provide for its laundering. Laundry personnel should be informed about the potential hazards of handling contaminated clothing and instructed about measures to minimize their health risk.

Protective clothing should be kept free of oil and grease and should be inspected and maintained regularly to preserve its effectiveness.

Protective clothing may interfere with the body's heat dissipation, especially during hot weather or during work in hot or poorly ventilated work environments.

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