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 This information may be superseded by new developments in the field of industrial hygiene.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

INTRODUCTION

This guideline summarizes pertinent information about furfural 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 Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new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(5)H(4)O(2)

* Structure

(For Structure, see paper copy)

* Synonyms

2-Furaldehyde, furfuraldehyde, artificial ant oil, fural, 2-furancarboxaldehyde, pyromucic aldehyde, 2-formylfuran, 2-furyl-methanal

* Identifiers

1. CAS No.: 98-01-1

2. RTECS No.: LT7000000

3. DOT UN: 1199 29

4. DOT label: Flammable liquid

* Appearance and odor

Furfural is a colorless to yellow, oily, combustible liquid that darkens to red-brown on exposure to light and air. It has an almond-like odor with an air odor threshold concentration of 0.078 part per million (ppm) part of air.

CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

1. Molecular weight: 96.08

2. Boiling point (at 760 mm Hg): 161.7 degrees C (323.06 degrees F)

3. Specific gravity: 1.1563 at 25 degrees C (77 degrees F)

4. Vapor density: 3.3

5. Melting point: -36.5 degrees C (-33.7 degrees F)

6. Vapor pressure at 20 degrees C (68 degrees F): 2 mm Hg

7. Solubility: Slightly soluble 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 furfural and strong acids or oxidizing materials should be avoided. An exothermic polymerization of almost explosive violence can occur upon contact with strong mineral acids or alkalies. If mixed with sodium hydrogen carbonate, ignition can occur spontaneously.

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

4. Special precautions: None reported.

* Flammability

The National Fire Protection Association has assigned a flammability rating of 2 (moderate fire hazard) to furfural.

1. Flash point: 60 degrees C (140 degrees F) (closed cup)

2. Autoignition temperature: 316 degrees C (600 degrees F)

3. Flammable limits in air (percent by volume): Lower, 2.1; upper, 19.3

4. Extinguishant: For small fires use dry chemical, carbon dioxide, water spray, or standard foam. Use water spray, fog, or standard foam to fight large fires involving furfural [DOT 1993, Guide 29].

Fires involving furfural should be fought upwind from the maximum distance possible. Keep unnecessary people away; isolate the hazard area and deny entry. Isolate the area for 1/2 mile in all directions if a tank, rail car, or tank truck is involved in the fire. Emergency personnel should stay out of low areas and ventilate closed spaces before entering. Vapors may travel to a source of ignition and flash back. Vapors are an explosion and poison hazard indoors, outdoors, or in sewers. Containers of furfural may explode in the heat of the fire and should be moved from the fire area if it is possible to do so safely. If this is not possible, cool fire exposed containers from the sides with water until well after the fire is out. Do not get water inside the containers. Stay away from the ends of containers. Personnel should withdraw immediately if a rising sound from a venting safety device is heard or if there is discoloration of a container due to fire. Firefighters should wear a full set of protective clothing and self-contained breathing apparatus when fighting fires involving furfural [DOT 1993, Guide 29].

EXPOSURE LIMITS

* OSHA PEL

The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for furfural is 5 ppm (20 milligrams per cubic meter (mg/m(3))) as an 8-hour time-weighted average (TWA) concentration. The OSHA PEL also bears a "Skin" notation, which indicates that the cutaneous route of exposure (including mucous membranes and eyes) contributes to overall exposure [29 CFR 1910.1000, Table Z-1].

* NIOSH REL

The National Institute for Occupational Safety and Health has not established a recommended exposure limit for furfural.

* ACGIH TLV

The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned furfural a threshold limit value (TLV) of 2 ppm (7.9 mg/m(3)) as a TWA for a normal 8-hour workday and a 40-hour workweek. The ACGIH also assigns a "Skin" notation to furfural [ACGIH 1994, p. 22].

* Rationale for Limits

The ACGIH limit is based on the risk of irritation [ACGIH 1991, p. 695].

HEALTH HAZARD INFORMATION

* Routes of Exposure

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

* Summary of toxicology

1. Effects on Animals: Furfural is an irritant of the skin, eyes, mucous membranes, and respiratory tract. It is a toxin to the central nervous system, liver, kidney, blood, and bone marrow. The oral LD(50) in rats is 65 mg/kg; and the inhalation LD(50) in rats is 260 ppm [NIOSH 1991]. Exposure of rats to furfural by ingestion or subcutaneous injection caused unsteadiness, paralysis, seizures, coma, and changes in liver, kidneys, blood, and bone marrow [Hathaway et al. 1991]. Cats exposed to 2,800 ppm for 30 minutes developed fatal pulmonary edema [Hathaway et al. 1991]. Solutions to 10 percent and 100 percent furfural instilled in rabbits' eyes caused pain in addition to transient swelling and redness of the lids and conjunctiva [Grant 1986]. Chronic dietary exposure to furfural caused liver cirrhosis in rats [NLM 1992]. Dogs exposed at 130 ppm for 6 hours a day for 4 weeks developed liver damage, but dogs exposed at 63 ppm did not [ACGIH 1991]. Rabbits exposed to furfural vapors for several hours daily developed liver and kidney lesions as well as changes in their blood profiles [Parmeggiani 1983]. Furfural is mutagenic in at least one bacterial species [NIOSH 1991].

2. Effects on Humans: Furfural is an irritant of the skin, eyes, mucous membranes, and respiratory tract. Concentrations of 1.9 to 14 ppm produced headache, itching of the throat, and redness and tearing of the eyes in some exposed workers [ACGIH 1991; Grant 1986]. Workers exposed to furfural vapors in a plant with inadequate ventilation reported numbness of the tongue and mucous membranes of the mouth, loss of taste sensation, and difficulty in breathing [ACGIH 1991]. Exposure to high concentrations has produced pulmonary edema [Parmeggiani 1983]. Damage to the eyesight of some individuals has also been reported [ACGIH 1991]. Chronic skin exposure may produce eczema, allergic skin sensitization, and photosensitization [Sittig 1991]. Furfural may cause a disulfiram-type reaction; that is, a worker exposed to furfural who has consumed alcohol may experience warmth and redness of the fact, a throbbing sensation and pain in the head and neck, difficulty in breathing, nausea, vomiting, sweating, thirst, chest pain, uneasiness, weakness, dizziness, blurred vision, and confusion. This effect may last from 30 minutes to several hours but does not appear to have residual side effects. By analogy with effects seen in animals, furfural may affect the central nervous system, liver, kidneys, blood, and bone marrow of humans; however, these effects have not been reported in exposed workers.

* Signs and symptoms of exposure

1. Acute exposure: Signs and symptoms of acute exposure to furfural include itching, burning, redness and taring of the eyes, and nasal stuffiness, dryness, soreness, or bloody discharge. Dryness or itching of the mouth or throat, numbness of the tongue and mucous membranes of the mouth, loss of taste sensation, fatigue, headache, and tremors have also been reported after exposure to furfural [Genium 1987; Sittig 1991].

2. Chronic exposure: Chronic skin exposure to furfural causes redness, itching, scaling, and photosensitization of the skin [Hathaway et al. 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 furfural and lead to worker exposures to this substance:

* The manufacture and transportation of furfural

* Use during removal of industrial coatings in open-surface tanks and in road construction

* Use as a wetting agent in manufacture of abrasive wheels; in the production of lysine

* Use in rubber or phenolic cement adhesives; as a laboratory reagent

* Use during molding of friction materials such as brake linings, clutch facings, brake blocks, etc.

* Use in manufactural of pharmaceuticals and furfural-phenol plastics, in the preparation of pyromucic acid; in manufacture of thermosetting resins; and as a solvent for nitrated cotton, nitrocellulose, shoe dyes, cellulose acetate, gums, synthetic and natural resins, dyes, and polymers

* Use in furfural spot test for meprobamate and other carbamates and liberated during use as a chemical intermediate in the manufacture of furan, tetrahydrofuran, tetrahydrofuryl alcohol, hexamethylene diamine, nylon, and adipic acid

* Liberated during dewaxing of oils, primarily lubricating oils; during decolorization of wood resins; in solvent-extraction processes in the petroleum refining industry; as a synthetic flavoring ingredient; as a herbicide, insecticide, germicide, and fungicide

* Liberated during separation of rosin, butadiene, benzene, and miscellaneous compounds from C(4) hydrocarbons and during manufacture of some polyurethane elastomers

* Use as a flotation agent and in the refining of rare earth and other metals

Methods that are effective in controlling worker exposures to furfural, 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 furfural 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 furfural, 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 and liver.

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 furfural 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 and liver.

* 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 furfural exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of furfural on the skin or liver. 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. Because occupational exposure to furfural may cause diseases with prolonged latent periods, the need for medical surveillance may extend well beyond the termination of employment.

* Biological monitoring

Biological monitoring involves sampling and analyzing body tissues or fluids to provide an index of exposure to a toxic substance or metabolite. A biological exposure index of 200 mg total furoic acid/g creatinine in urine collected at the end of the workshift has been correlated to exposure at the ACGIH-TLV.

WORKPLACE MONITORING AND MEASUREMENT

Determination of a worker's exposure to airborne furfural is made using a petroleum based charcoal tube (100/50 mg sections, 20/40 mesh. Samples are collected at a maximum flow rate of 1 liter/minute until a maximum collection volume of 180 liters is reached. The sample is then treated with 99:1 carbon disulfide:dimethylformamide. Analysis is conducted by gas chromatography using a flame ionization detector (GC/FID). This method (OSHA 72) is fully validated and is described in the OSHA Computerized Information System [OSHA 1994]. NIOSH has published a similar method (Method No. 2529) that requires the use of a XAD-2 tube. The sample is treated with toluene. Analysis is performed using gas chromatography (GC/FID) [NIOSH 1994].

PERSONAL HYGIENE PROCEDURES

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

Clothing contaminated with furfural 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 furfural, particularly its potential for causing irritation.

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

STORAGE

Furfural 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 furfural should be protected from physical damage and should be stored separately from strong acids, oxidizing materials, strong mineral acids, alkalies, or sodium hydrogen carbonate.

SPILLS AND LEAKS

In the event of a spill or leak involving furfural, 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. Use water spray to reduce vapors; do not get water inside container. Do not flush waste to sewers or open waterways.

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

8. For large liquid spills, build dikes far ahead of the spill to contain the furfural 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

Furfural 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 furfural 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 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 furfural 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. Furfural is listed as a hazardous waste under RCRA and has been assigned EPA Hazardous Waste No. U125. This substance has been banned from land disposal until treated by fuel substitution or incineration.

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 furfural 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 furfural. 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 furfural. The resistance of various materials to permeation by furfural is shown below:

(*) Not recommended, degradation may occur

To evaluate the use of these PPE materials with furfural, 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 furfural.

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.

Amoore JE, Hautala E [1983]. 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. J of App Tox 3(6):272- 290.

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Genium [1987]. Material safety data sheet No. 413. Schenectady, NY: Genium Publishing Corporation.

Grant WM [1986]. Toxicology of the eye. 3rd ed. Springfield, IL: Charles C Thomas.

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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 [1991]. Registry of toxic effects of chemical substances: Furfural. 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.

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