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 This information may be superseded by new developments in the field of industrial hygiene.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 DIMETHYLPHTHALATE

INTRODUCTION

This guideline summarizes pertinent information about dimethylphthalate 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 Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new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(10)H(10)O(4)

* Structure

(For Structure, see paper copy)

* Synonyms

DMP; dimethyl 1,2-benzenedicarboxylate; phthalic acid dimethyl ester;

1,2-benzenedicarboxylic acid dimethyl ester; fermine; mipax; NTM, solvanom; solvarone; palation M; avolin; methyl phthalate

* Identifiers

1. CAS No.: 131-11-3

2. RTECS No.: TI1575000

3. Specific DOT number: None.

4. Specific DOT label: None.

* Appearance and odor

Dimethylphthalate is a colorless, oily liquid with a slight ester odor. It occurs as a pale yellow crystalline substance at temperatures below 0-2degreesC (32-35.6degreesF).

CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

1. Molecular weight: 194.2

2. Boiling point (at 760 mm Hg): 283.7 degrees C (542.7 degrees F)

3. Specific gravity (water = 1): 1.19 at 20 degrees C (68 degrees F)

4. Vapor density: 6.7

5. Melting point: 5.5 degrees C (41.9 degrees F)

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

7. Solubility: Practically insoluble in water; miscible with alcohol, ether, and chloroform.

8. Evaporation rate: Data not available.

* Reactivity

1. Conditions contributing to instability: Heat or flame.

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

3. Hazardous decomposition products: Toxic gases and vapors (such as oxides of carbon) may be released in a fire involving dimethylphthalate.

4. Special precautions: None reported.

* Flammability

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

1. Flash point: 146 degrees C (295 degrees F)

2. Autoignition temperature: 555 degrees C (1031 degrees F)

3. Flammable limits in air (percent by volume): Lower, 0.94; upper, data not available

4. Extinguishant: For fires involving dimethylphthalate use water spray, dry chemical, carbon dioxide, or foam.

Fires involving dimethylphthalate should be fought upwind from the maximum distance possible. Use water spray to cool fire exposed containers and other combustibles. Water or foam may cause frothing. Firefighters should wear a full set of protective clothing and self-contained breathing apparatus when fighting fires involving dimethylphthalate.

EXPOSURE LIMITS

The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for dimethylphthalate is 5 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 dimethylphthalate of 5 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 dimethylphthalate a threshold limit value (TLV) of 5 mg/m(3) as a TWA for a normal 8-hour workday and a 40-hour workweek [ACGIH 1994, p. 20].

* Rationale for Limits

The NIOSH limit is based on the risk of eye and upper respiratory irritation [NIOSH 1992].

The ACGIH limit is based on controlling excess mist rather than to protect against toxic effects [ACGIH 1991, p. 495].

HEALTH HAZARD INFORMATION

* Routes of Exposure

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

* Summary of toxicology

1. Effects on Animals: Dimethylphthalate has a low order of acute toxicity but is embryotoxic and teratogenic in mice and rats. In the litters of rat dams injected with 10 percent, 33 percent, or 50 percent of the LD(50) dose of dimethylphthalate on the fifth, tenth, and fifteenth days of gestation, an increased incidence of fetal resorption and skeletal abnormalities was observed [Hathaway et al. 1991]. The acute oral LD(50) for exposure to dimethylphthalate is 4.4 g/kg in rabbits, 2.4 g/kg for guinea pigs, and 6.8 g/kg for rats [NIOSH 1991]. The LD(50) for acute dermal exposure is greater than 20 ml/kg in rabbits [Clayton and Clayton 1982]. In chronic feeding studies of 4 percent and 8 percent dimethylphthalate, rats exposed for 2 years all showed growth changes that were slight but significant. In the animals exposed orally to 8 percent, kidney damage was noted. These animals did not show an increase in mortality [Hathaway et al. 1991]. When applied to 10 percent of the body surface of rabbits for 90 days, exposure to 4.0 ml dimethylphthalate per kilogram of body weight caused some deaths. Autopsy findings included pulmonary edema and kidney damage. When undiluted dimethylphthalate was instilled into the eyes of rabbits, no observable effects were noted after 48 hours [Hathaway et al. 1991].

2. Effects on Humans: Dimethylphthalate has been used as an insect repellant since World War II; there are no reported cases of skin irritation or sensitization. This substance is only very slowly absorbed through the skin. Ingestion causes gastrointestinal irritation, hypotension, and coma. It is also reported to be a central nervous system depressant. In one fatal case of a suicidal ingestion of a mixture containing dimethylphthalate and ketone peroxides, the principal toxic symptoms were marked esophagitis and gastritis with hemorrhage [NLM 1992; Clayton and Clayton 1982]. Dimethylphthalate has been reported to be irritating to the nose, mouth, and throat [Sittig 1991]. If splashed in the eyes, it causes considerable eye pain but no, or very slight, reversible damage [Grant 1986].

* Signs and symptoms of exposure

1. Acute exposure: If splashed into the eye, dimethylphthalate causes pain and may cause mild and transient damage [Grant 1986]. Ingestion causes irritation of the esophagus and stomach with hemorrhage, vomiting, diarrhea, possible central nervous system depression, coma, and hypotension. It is also reported to cause burning of the lips, tongue, and mouth. Inhalation produces coughing [Sittig 1991; Genium 1987].

2. Chronic exposure: No signs or symptoms of chronic exposure to dimethylphthalate have been reported in humans.

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 dimethylphthalate and lead to worker exposures to this substance:

* The manufacture and transportation of dimethylphthalate

* Used as a plasticizer in compounding of plastics, primarily cellulose acetate, nitrocellulose, ethylcellulose, cellulose acetate butyrate, polystyrene, polyvinyl acetate, polyvinyl butyral, and polyvinyl chloride

* Used during manufacture of surface coatings containing plasticized resins and polymers, including furniture lacquers, printing inks, textile and paper coatings, molding powders, moistureproof coatings for cellophane, and safety glass

* Used in solid rocket propellants

* Liberated during molding, casting, extrusion, or other processing of heated, plasticized resins and polymers in manufacture of plastic articles

* Liberated during manufacture and use of insect repellant formulations, perfumes, and hair sprays

Methods that are effective in controlling worker exposures to dimethylphthalate, 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 dimethylphthalate 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 dimethylphthalate, 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 system. Medical surveillance for respiratory disease should be conducted using the principles and methods recommended by the American Thoracic Society.

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 dimethylphthalate 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 system.

* 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 dimethylphthalate exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of dimethylphthalate on the respiratory system. 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 dimethylphthalate.

WORKPLACE MONITORING AND MEASUREMENT

Determination of a worker's exposure to airborne dimethylphthalate 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 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 fully validated and described in the OSHA Computerized Information System [OSHA 1994].

PERSONAL HYGIENE PROCEDURES

If dimethylphthalate contacts the skin, workers should immediately wash the affected areas with soap and water.

Clothing contaminated with dimethylphthalate 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 dimethylphthalate, particularly its potential for causing eye and mucous membrane irritation.

A worker who handles dimethylphthalate 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 dimethylphthalate or a solution containing dimethylphthalate is handled, processed, or stored.

STORAGE

Dimethylphthalate 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 dimethylphthalate should be protected from physical damage and ignition sources, and should be stored separately from nitrates, strong oxidizers, strong alkalies, and strong acids.

SPILLS AND LEAKS

In the event of a spill or leak involving dimethylphthalate, persons not wearing protective equipment and fully-encapsulating, vapor-protective 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. Use water spray to reduce vapors.

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

Dimethylphthalate 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 dimethylphthalate is 5,000 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 dimethylphthalate per calendar year or otherwise use 10,000 pounds or more of dimethylphthalate 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 dimethylphthalate 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. Dimethylphthalate is listed as a hazardous waste under RCRA and has been assigned EPA Hazardous Waste No. U102. It is approved for land disposal after treatment and only if the concentration of dimethylphthalate 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 dimethylphthalate 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 dimethylphthalate. 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 dimethylphthalate. Few reports have been published on the resistance of various materials to permeation by dimethylphthalate. However, the resistance of one material to permeation by the chemically similar diethylphthalate is shown below:

To evaluate the use of this or other PPE materials with dimethylphthalate, 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 dimethylphthalate.

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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