OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR WOOD DUST, ALL SOFT AND HARDWOODS, EXCEPT WESTERN RED CEDAR INTRODUCTION
This guideline summarizes pertinent information about wood dust, all soft and hardwoods, except western red cedar 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 Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new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 Not applicable. * Structure (For Structure, see paper copy) * Synonyms Finely divided wood particles, powdered wood, sawdust, wood flour, hardwood dust, wood shavings, softwood dust, wood dust * Identifiers 1. CAS No.: Data not available. 2. RTECS No.: ZC9850000 3. Specific DOT number: None 4. Specific DOT label: None * Appearance and odor This type of wood dust consists of the dust from all hard and soft woods with the exception of western red cedar. It is pulverized wood wastes, or the dusts from cutting, shaping, drilling, sanding, or general handling of wood.
CHEMICAL AND PHYSICAL PROPERTIES
* Physical data
1. Molecular weight: Not applicable.
1. Conditions contributing to instability: Heat, sparks
or open flames.
* Flammability The National Fire Protection Association has not assigned a flammability rating to these wood dusts.
Other sources rate wood dust as a combustible solid when this substance is exposed to heat or open flame.
1. Flash point: Not applicable.
* OSHA PEL
The Occupational Safety and Health Administration (OSHA) has established a permissible exposure limit (PEL) of 15 milligrams per cubic meter (mg/m(3)) of air for the total dust and 5 mg/m(3) for the respirable fraction of wood dust, all soft and hardwoods, except western red cedar (as a nuisance dust) [29 CFR 1910. 1000, Table Z-3].
* NIOSH REL
The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for wood dust, all soft and hardwoods, except western red cedar of 1 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 wood dust, all soft and hardwoods, except western red cedar a threshold limit value (TLV) of 1 mg/m(3) for certain hardwoods, such as beech and oak, and 5 mg/m(3) for soft wood, as TWAs for a normal 8-hour workday and a 40-hour workweek and a short-term exposure limit (STEL) of 10 mg/m(3) for soft wood, for periods not to exceed 15 minutes. Exposures at the STEL concentration should not be repeated more than four times a day and should be separated by intervals of at least 60 minutes [ACGIH 1994, p. 36].
* Rationale for Limits
The NIOSH limit is based on the risk of pulmonary dysfunction and respiratory effects [NIOSH 1992].
The ACGIH limits are based on the risk of impaired nasal mucociliary function, potential nasal adenocarcinoma, and related hyperplasias (1 mg/m(3) TWA for hardwoods), and dermatitis and upper respiratory tract disease (for softwoods) [ACGIH 1991, pp. 1729-1730].
HEALTH HAZARD INFORMATION
* Routes of Exposure
Exposure to wood dust can occur through inhalation, and eye or skin contact.
* Summary of toxicology
1. Effects on Animals: There is limited data available
on the toxicology of wood dusts in animals. A methanol extract of beech
wood dust was mutagenic in the Ames assay in the presence of an exogenous
metabolic system [IARC 1987]. Among hamsters exposed by inhalation to
fine particles of beech wood dust, one animal out of 22 had a nasal tumor
[IARC 1987]. IARC concluded that there is inadequate evidence for the
carcinogenicity of wood dust to experimental animals [IARC 1987].
* Signs and symptoms of exposure
1. Acute exposure: Acute exposure to wood dusts can result in eye and skin irritation, asthma, erythema, blistering, erosion and secondary infections of the skin, redness, scaling, itching, and vesicular dermatitis.
2. Chronic exposure: Chronic exposure to wood dusts can result in dermatitis reactions, asthma, pneumonitis, and coughing, wheezing, fever and the other signs and symptoms associated with chronic bronchitis. Chronic exposure may also result in nasal cancer.
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 wood dust and lead to worker exposures to these dusts
The logging and transportation of wood
Methods that are effective in controlling worker exposures to wood dust, all soft and hardwoods, except western red cedar, depending on the feasibility of implementation, are as follows:
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 . Industrial ventilation--a manual of recommended practice. 21st ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.
2. Burton DJ . Industrial ventilation--a self study companion. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.
3. Alden JL, Kane JM . Design of industrial ventilation systems. New York, NY: Industrial Press, Inc.
4. Wadden RA, Scheff PA . Engineering design for control of workplace hazards. New York, NY: McGraw-Hill.
5. Plog BA . Fundamentals of industrial hygiene. Chicago, IL: National Safety Council.
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 wood dust, all soft and hardwoods, except western red cedar 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 wood dust, 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 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 wood dust 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 or 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 wood dust exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of wood dust on the skin or 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. Because occupational exposure to wood dust 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. No biological monitoring test acceptable for routine use has yet been developed for wood dust.
WORKPLACE MONITORING AND MEASUREMENT
Determination of a worker's exposure to airborne wood dust is made using a tared low ash polyvinyl chloride filter (5 microns) preceded for respirable fraction sampling by a 10 mm nylon cyclone. Samples are collected at a maximum flow rate of 1.7 liters/minute (respirable fraction) or 2.0 liters/minute (total dust) until a maximum collection volume of 816 liters (respirable fraction) or 960 liters (total dust) is reached. Analysis is conducted by gravimetric methods. This method (for nuisance dusts) is described in the OSHA Computerized Information System [OSHA 1994] and is fully validated. NIOSH has published a similar methods (Method No. 0500 and 0600) for the sampling and analysis of nuisance dusts [NIOSH 1994b].
PERSONAL HYGIENE PROCEDURES
If wood dust contacts the skin, workers should wash the affected areas with soap and water.
Clothing contaminated with wood dust should be removed, 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 wood dust.
A worker who handles wood dust 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 wood dust is handled, or processed.
Wood dust 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 wood dust should be protected from physical damage and stored separately from all sources of ignition.
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
Wood dust 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 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 wood dust; there is no reportable quantity for these substances.
* 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 wood dust 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 wood dust 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.
* 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 wood dust 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].
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 wood dust. 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 wood dust.
To evaluate the use of PPE materials with wood dust, 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 wood dust.
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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