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 This information may be superseded by new developments in the field of industrial hygiene.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

INTRODUCTION

This guideline summarizes pertinent information about dibutyl phenyl phosphate 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 Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new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(14)H(23)PO(4)

* Structure

(For Structure, see paper copy)

* Synonyms

DBPP; phosphoric acid, dibutyl phenyl ester

* Identifiers

1. CAS No.: 2528-36-1

2. RTECS No.: TB9626600

3. Specific DOT number: None

4. Specific DOT label: None

* Appearance and odor

Dibutyl phenyl phosphate is a clear, slightly yellow liquid with an odor similar to butanol.

CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

1. Molecular weight: 286.26

2. Boiling point (at 760 mm Hg): 131 degrees to 132 degrees C (267.8 degrees to 269.6 degrees F)

3. Specific gravity: Data not available.

4. Vapor density: Data not available.

5. Melting point: Data not available.

6. Vapor pressure at 25 degrees C (77 degrees F): 0.007 mm Hg

7. Solubility: Essentially insoluble in water.

8. Evaporation rate: Data not available.

* Reactivity

1. Conditions contributing to instability: None reported.

2. Incompatibilities: None reported.

3. Hazardous decomposition products: None reported.

4. Special precautions: None reported.

* Flammability

The National Fire Protection Association has not assigned a flammability rating to dibutyl phenyl phosphate. Other sources rate dibutyl phenyl phosphate as combustible when this substance is exposed to heat or open flame.

1. Flash point: 129 degrees C (264.2 degrees F) (closed cup)

2. Autoignition temperature: Data not available.

3. Flammable limits in air: Data not available.

4. Extinguishant: Use an extinguishant that is suitable for the materials involved in the surrounding fire.

Fires involving dibutyl phenyl phosphate should be fought upwind from the maximum distance possible. Isolate the hazard area and deny access to unnecessary personnel. Firefighters should wear a full set of protective clothing and self-contained breathing apparatus when fighting fires involving dibutyl phenyl phosphate.

EXPOSURE LIMITS

* OSHA PEL

The Occupational Safety and Health Administration (OSHA) does not currently regulate dibutyl phenyl phosphate.

* NIOSH REL

The National Institute for Occupational Safety and Health (NIOSH) has not established a recommended exposure limit for dibutyl phenyl phosphate.

* ACGIH TLV

The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned dibutyl phenyl phosphate a threshold limit value (TLV) of 0.3 part per million (ppm) parts of air (3.5 milligrams per cubic meter (mg/m(3))) as a TWA for a normal 8-hour workday and a 40-hour workweek. The ACGIH assigns a "Skin" notation, which indicates that the cutaneous route of exposure (including mucous membranes and eyes) contributes to overall exposure [ACGIH 1994, p. 19].

* Rationale for Limits

The ACGIH limit is based on the risk of irritation [ACGIH 1991, p. 398].

HEALTH HAZARD INFORMATION

* Routes of Exposure

Exposure to dibutyl phenyl phosphate can occur through inhalation, ingestion, and eye and skin contact [ACGIH 1991, page 397].

* Summary of toxicology

1. Effects on Animals: Dibutyl phenyl phosphate can damage the skin, nervous system, liver, bladder and the reproductive system in animals [ACGIH 1991; NIOSH 1994]. The dermal LD(50) in rabbits is greater than 5,000 mg/kg. The oral LD(50) in rats is 2,140 mg/kg [NIOSH 1994]. Dibutyl phenyl phosphate is a neurotoxic agent. Reduction in plasma, erythrocyte and brain cholinesterase activity was observed in rabbits exposed to 1,000 mg/kg/day, 5 days/week for 3 weeks; reduction in plasma cholinesterase activity was also observed in rabbits exposed to 100 mg/kg/day, but not in those animals exposed to 10 mg/kg/day [ACGIH 1991]. Decreased muscle tonality was observed in rabbits exposed daily by skin contact for 21 days; significant irritation was produced as well as edema, desquamation, coriaceous, and fissuring [ACGIH 1991]. Dibutyl phenyl phosphate can also affect the liver, lungs, urinary tract and reproductive system. Rats administered doses of 50, 150, or 500 mg/kg/day in the diet for 90 days developed multifocal hepatocellular degeneration, bladder transitional cell hyperplasia, and interstitial cell hypertrophy of the ovary [ACGIH 1991]. A reduction in platelets was also reported, and increased liver weights and decreased lung weights were observed in rats exposed to 150 or 500 mg/kg/day [ACGIH 1991]. No adverse effects were observed in a subsequent study at 5 mg/kg/day [ACGIH 1991]. Offspring of rats administered dibutyl phenyl phosphate orally had decreased viability [NIOSH 1994]. Dibutyl phenyl phosphate was not mutagenic in experimental test systems [ACGIH 1991].

2. Effects on Humans: Dibutyl phenyl phosphate can injure the eyes and is irritating to the skin and upper respiratory tract in humans [ACGIH 1991]. Contact of the eyes with dibutyl phenyl phosphate caused marked pain [ACGIH 1991]. Repeated dermal contact with dibutyl phenyl phosphate has caused drying and cracking of exposed skin [ACGIH 1991]. Exposure to aerosolized or vaporized dibutyl phenyl phosphate has caused nose and throat irritation accompanied by coughing and wheezing [ACGIH 1991]. Based on the results of patch tests on human volunteers, dibutyl phenyl phosphate is not considered a primary irritant or a sensitizing agent [ACGIH 1991].

* Signs and symptoms of exposure

1. Acute exposure: Acute exposure to dibutyl phenyl phosphate may cause irritation to the eyes and mucous membranes.

2. Chronic exposure: Chronic dermal exposure to dibutyl phenyl phosphate may cause dermatitis.

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 phenyl phosphate and lead to worker exposures to this substance:

* The manufacture and transportation of dibutyl phenyl phosphate

* Use in hydraulic fluids

Methods that are effective in controlling worker exposures to dibutyl phenyl phosphate, 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 phenyl phosphate 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 phenyl phosphate, 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 skin, eyes, and upper respiratory tract.

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 phenyl phosphate 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 skin, eyes, or upper respiratory tract.

* 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 phenyl phosphate exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of dibutyl phenyl phosphate on the skin, eyes, or upper respiratory tract. 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 phenyl phosphate.

WORKPLACE MONITORING AND MEASUREMENT

No method for the determination of a worker's exposure to airborne dibutyl phenyl phosphate has been published.

PERSONAL HYGIENE PROCEDURES

If dibutyl phenyl phosphate 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 phenyl phosphate 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 phenyl phosphate.

A worker who handles dibutyl phenyl phosphate 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 phenyl phosphate or a solution containing dibutyl phenyl phosphate is handled, processed, or stored.

STORAGE

Dibutyl phenyl phosphate 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 phenyl phosphate should be protected from physical damage and heat and should be stored separately from incompatible chemicals.

SPILLS AND LEAKS

In the event of a spill or leak involving dibutyl phenyl phosphate, 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. Do not touch the spilled material; stop the leak if it is possible to do so without risk.

2. Notify safety personnel of large spills or leaks.

3. Remove all sources of heat and ignition.

4. Ventilate the area of the spill or leak.

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

6. For large liquid spills, build dikes far ahead of the spill to contain the dibutyl phenyl phosphate 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 phenyl phosphate 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].

Employers are not required by the emergency release notification provisions in 40 CFR Part 355.40 to notify the National Response Center of an accidental release of dibutyl phenyl phosphate; there is no reportable quantity for this substance.

* Community right-to-know requirements

Employers are not required by EPA in 40 CFR Part 372.30 to submit a Toxic Chemical Release Inventory form (Form R) to EPA reporting the amount of dibutyl phenyl phosphate 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. Although dibutyl phenyl phosphate is not specifically listed as a hazardous waste under RCRA, EPA requires employers to treat waste as hazardous if it exhibits any of the characteristics discussed above.

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 phenyl phosphate 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 phenyl phosphate. 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 phenyl phosphate.

There are no published reports on the resistance of various materials to permeation by dibutyl phenyl phosphate.

To evaluate the use of PPE materials with dibutyl phenyl phosphate, 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 phenyl phosphate.

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.

REFERENCES

ACGIH [1991]. Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

ACGIH [1994]. 1994-1995 Threshold limit values for chemical substances and physical agents and biological exposure indices. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

CFR. Code of Federal regulations. Washington, DC: U.S. Government Printing Office, Office of the Federal Register.

Lewis RJ, ed. [1993]. Hawley's condensed chemical dictionary. 12th ed. New York, NY: Van Nostrand Reinhold Company.

Mickelsen RL, Hall RC [1987]. A breakthrough time comparison of nitrile and neoprene glove materials produced by different glove manufacturers. Am Ind Hyg Assoc J 48(11): 941-947.

Mickelsen RL, Hall RC, Chern RT, Myers JR [1991]. Evaluation of a simple weight-loss method for determining the permeation of organic liquids through rubber films. Am Ind Hyg Assoc J 52(10): 445-447.

NIOSH [1987a]. NIOSH guide to industrial respiratory protection. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-116.

NIOSH [1987b]. NIOSH respirator decision logic. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-108.

NIOSH [1994]. Registry of toxic effects of chemical substances: Dibutyl phenyl phosphate. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Division of Standards Development and Technology Transfer, Technical Information Branch.

NLM [1993]. Hazardous substances data bank: Dibutyl phenyl phosphate. Bethesda, MD: National Library of Medicine.

USC. United States code. Washington. DC: U.S. Government Printing Office.