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Sampling Strategy
Once the employer determines that there is a possibility of substantial employee exposure to formaldehyde, the employer is obligated to measure employee exposure.
The next step is selection of a maximum risk employee. When there are different processes where employees may be exposed to formaldehyde, a maximum risk employee should be selected for each work operation.
Selection of the maximum risk employee requires professional judgment. The best procedure for selecting the maximum risk employee is to observe employees and select the person closest to the source of formaldehyde. Employee mobility may affect this selection; e.g., if the closest employee is mobile in his tasks, he may not be the maximum risk employee. Air movement patterns and differences in work habits will also affect selection of the maximum risk employee.
When many employees perform essentially the same task, a maximum risk employee cannot be selected. In this circumstance, it is necessary to resort to random sampling of the group of workers. The objective is to select a subgroup of adequate size so that there is a high probability that the random sample will contain at least one worker with high exposure if one exists. The number of persons in the group influences the number that need to be sampled to ensure that at least one individual from the highest 10 percent exposure group is contained in the sample. For example, to have 90 percent confidence in the results, if the group size is 10, nine should be sampled; for 50, only 18 need to be sampled.
If measurement shows exposure to formaldehyde at or above the action level or the STEL, the employer needs to identify all other employees who may be exposed at or above the action level or STEL and measure or otherwise accurately characterize the exposure of these employees.
Whether representative monitoring or random sampling are conducted, the purpose remains the same -to determine if the exposure of any employee is above the action level. If the exposure of the most exposed employee is less than the action level and the STEL, regardless of how the employee is identified, then it is reasonable to assume that measurements of exposure of the other employees in that operation would be below the action level and theSTEL.
Exposure Measurements
There is no "best" measurement strategy for all situations. Some elements to consider in developing a strategy are:
(1) Availability and cost of sampling equipment,
(2) Availability and cost of analytic facilities,
(3) Availability and cost of personnel to take samples,
(4) Location of employees and work operations,
(5) Intraday and interday variations in the process,
(6) Precision and accuracy of sampling and analytic methods, and
(7) Number of samples needed.
Samples taken for determining compliance with STEL differ from those that measure the TWA concentration in important ways. STEL samples are best taken in a non-random fashion using all available knowledge relating to the area, the individual, and the process to obtain samples during periods of maximum expected concentrations. At least three measurements on a shift are generally needed to spot gross errors or mistakes; however, only the highest value represents the STEL.
If an operation remains constant throughout the workshift, a much greater number of samples would need to be taken over the 32 discrete non-overlapping periods in an 8-hour workshift to verify compliance with a STEL. If employee exposure is truly uniform throughout the workshift, an employer in compliance with the 1 ppm TWA would be in compliance with the 2 ppm STEL, and this determination can probably be made using objective data.
Need to Repeat the Monitoring Strategy
Interday and intraday fluctuations in employee exposure are mostly influenced by the physical processes that generate formaldehyde and the work habits of the employee. Hence, implant process variations influence the employer's determination of whether or not additional controls need to be imposed. Measurements that employee exposure is low on a day that is not representative of worst conditions may not provide sufficient information to determine whether or not additional engineering controls should be installed to achieve the PELs.
The person responsible for conducting sampling must be aware of systematic changes which will negate the validity of the sampling results. Systematic changes in formaldehyde exposure concentration for an employee can occur due to:
(1) The employee changing patterns of movement in the workplace,
(2) Closing of plant doors and windows,
(3) Changes in ventilation from season to season,
(4) Decreases in ventilation efficiency or abrupt failure of engineering control equipment, and
(5) Changes in the production process or work habits of the employee. Any of these changes, if they may result in additional exposure that reaches the next level of action (i.e., 0.5 or 1.0 ppm as an 8-hr average or 2 ppm over 15 minutes) require the employer to perform additional monitoring to reassess employee exposure.
A number of methods are suitable for measuring employee exposure to formaldehyde or for characterizing emissions within the worksite. The preamble to this standard describes some methods that have been widely used or subjected to validation testing. A detailed analytical procedure derived from the OSHA Method 52 for acrolein and formaldehyde is presented below for informational purposes.
Inclusion of OSHA's method in this appendix in no way implies that it is the only acceptable way to measure employee exposure to formaldehyde. Other methods that are free from significant interferences and that can determine formaldehyde at the permissible exposure limits within z 25 percent of the "true" value at the 95 percent confidence level are also acceptable. Where applicable, the method should also be capable of measuring formaldehyde at the action level to z 35 percent of the "true" value with a 95 percent confidence level. OSHA encourages employers to choose methods that will be best for their individual needs. The employer must exercise caution, however, in choosing an appropriate method since some techniques suffer from interferences that are likely to be present in workplaces of certain industry sectors where formaldehyde is used.
OSHA's Analytical Laboratory Method
Method: No. 52
Matrix: Air
Target Concentration: 1 ppm (1.2 mg/m [FN3])
Procedures: Air samples are collected by drawing known volumes of air through sampling tubes containing XAD-2 adsorbent which have been coated with 2- (hydroxymethyl) piperidine. The samples are desorbed with toluene and then analyzed by gas chromatography using a nitrogen selective detector.
Recommended Sampling Rate and Air Volumes: 0.1L/min and 24 L

Reliable Quantitation Limit: 16 ppb (20ug/m [FN3])
Standard Error of Estimate of the Target Concentration: 7.3%
Status of the Method: A sampling and analytical method that has been subjected to the established evaluation procedures of the Organic Methods of Evaluation Branch.
Date: March 1985
1. General Discussion
1.1 Background: The current OSHA method for collecting acrolein vapor recommends the use of activated 13X molecular sieves. The samples must be stored in an ice bath during and after sampling and also they must be analyzed within 48 hours of collection. The current OSHA method for collecting formaldehyde vapor recommends the use of bubblers containing 10% methanol in water as the trapping solution.
This work was undertaken to resolve the sample stability problems associated with acrolein and also to eliminate the need to use bubblers to sample formaldehyde. A goal of this work was to develop and/or to evaluate a common sampling and analytical procedure for acrolein and formaldehyde.
NIOSH has developed independent methodologies for acrolein and formaldehyde which recommend the use of reagent-coated adsorbent tubes to collect the aldehydes as stable derivatives. The formaldehyde sampling tubes contain Chromosorb 102 adsorbent coated with N-benzylethanolamine (BEA) which reacts with formaldehyde vapor to form a stable oxazolidine compound. The acrolein sampling tubes contain XAD-2 adsorbent coated with 2-(hydroxymethyl) piperidine (2-HMP) which reacts with acrolein vapor to form a different, stable oxazolidine derivative. Acrolein does not appear to react with BEA to give a suitable reaction product. Therefore, the formaldehyde procedure cannot provide a common method for both aldehydes. However, formaldehyde does react with 2-HMP to form a very suitable reaction product. It is the quantitative reaction of acrolein and formaldehyde with 2-HMP that provides the basis for this evaluation.
This sampling and analytical procedure is very similar to the method recommended by NIOSH for acrolein. Some changes in the NIOSH methodology were necessary to permit the simultaneous determination of both aldehydes and also to accommodate OSHA laboratory equipment and analytical techniques.
1.2 Limit-defining parameters: The analyte air concentrations reported in this method are based on the recommended air volume for each analyte collected separately and a desorption volume of 1 mL. The amounts are presented as acrolein and/or formaldehyde, even though the derivatives are the actual species analyzed.
1.2.1 Detection limits of the analytical procedure: The detection limit of the analytical procedure was 386 pg per injection for formaldehyde. This was the amount of analyte which gave a peak whose height was about five times the height of the peak given by the residual formaldehyde derivative in a typical blank front section of the recommended sampling tube.
1.2.2 Detection limits of the overall procedure: The detection limits of the overall procedure were 482 ng per sample (16 ppb or 20 ug/m [FN3] for formaldehyde). This was the amount of analyte spiked on the sampling device which allowed recoveries approximately equal to the detection limit of the analytical procedure.
1.2.3 Reliable quantitation limits: The reliable quantitation limit was 482 ng per sample (16 ppb or 20 ug/m [FN3]) for formaldehyde. These were the smallest amounts of analyte which could be quantitated within the limits of a recovery of at least 75% and a precision (+- 1.96 SD)of +- 25% or better.
The reliable quantitation limit and detection limits reported in the method are based upon optimization of the instrument for the smallest possible amount of analyte. When the target concentration of an analyte is exceptionally higher than these limits, they may not be attainable at the routine operating parameters.
1.2.4 Sensitivity: The sensitivity of the analytical procedure over concentration ranges representing 0.4 to 2 times the target concentration, based on the recommended air volumes, was 7,589 area units per ug/mL for formaldehyde. This value was determined from the slope of the calibration curve. The sensitivity may vary with the particular instrument used in the analysis.
1.2.5 Recovery: The recovery of formaldehyde from samples used in an 18-day storage test remained above 92% when the samples were stored at ambient temperature. These values were determined from regression lines which were calculated from the storage data. The recovery of the analyte from the collection device must be at least 75% following storage.
1.2.6 Precision (analytical method only): The pooled coefficient of variation obtained from replicate determinations of analytical standards over the range of 0.4 to 2 times the target concentration was 0.0052 for formaldehyde (section 4.3).
1.2.7 Precision (overall procedure): The precision at the 95% confidence level for the ambient temperature storage tests was +- 14.3% for formaldehyde. These values each include an additional +- 5% for sampling error. The overall procedure must provide results at the target concentrations that are +- 25% at the 95% confidence level.
1.2.8 Reproducibility: Samples collected from controlled test atmospheres and a draft copy of this procedure were given to a chemist unassociated with this evaluation. The formaldehyde samples were analyzed following 15 days storage. The average recovery was 96.3% and the standard deviation was 1.7%.
1.3 Advantages:
1.3.1 The sampling and analytical procedures permit the simultaneous determination of acrolein and formaldehyde.
1.3.2 Samples are stable following storage at ambient temperature for at least 18 days.
1.4 Disadvantages: None.
2. Sampling Procedure
2.1 Apparatus:
2.1.1 Samples are collected by use of a personal sampling pump that can be calibrated to within +- 5% of the recommended 0.1L/min sampling rate with the sampling tube in line.
2.1.2 Samples are collected with laboratory prepared sampling tubes. The sampling tube is constructed of silane treated glass and is about 8-cm long. The ID is 4 mm and the OD is 6 mm. One end of the tube is tapered so that a glass wool end plug will hold the contents of the tube in place during sampling. The other end of the sampling tube is open to its full 4-mm ID to facilitate packing of the tube. Both ends of the tube are firepolished for safety. The tube is packed with a 75-mg backup section, located nearest the tapered end and a 150-mg sampling section of pretreated XAD-2 adsorbent which has been coated with 2-HMP. The two sections of coated adsorbent are separated and retained with small plugs of silanized glass wool. Following packing, the sampling tubes are sealed with two 7/32 inch OD plastic end caps. Instructions for the pretreatment and the coating of XAD-2 adsorbent are presented in section 4 of this method.
2.1.3 Sampling tubes, similar to those recommended in this method, are marketed by Supelco, Inc. These tubes were not available when this work was initiated, therefore, they were not evaluated.
2.2 Reagents: None required.
2.3 Technique:
2.3.1 Properly label the sampling tube before sampling and then remove the plastic end caps.
2.3.2 Attach the sampling tube to the pump using a section of flexible plastic tubing such that the large, front section of the sampling tube is exposed directly to the atmosphere. Do not place any tubing ahead of the sampling tube. The sampling tube should be attached in the worker's breathing zone in a vertical manner such that it does not impede work performance.
2.3.3 After sampling for the appropriate time, remove the sampling tube from the pump and then seal the tube with plastic end caps.
2.3.4 Include at least one blank for each sampling set. The blank should be handled in the same manner as the samples with the exception that air is not drawn through it.
2.3.5 List any potential interferences on the sample data sheet.
2.4 Breakthrough:
2.4.1 Breakthrough was defined as the relative amount of analyte found on a backup sample in relation to the total amount of analyte collected on the sampling train.
2.4.2 For formaldehyde collected from test atmospheres containing 6 times the PEL, the average 5% breakthrough air volume was 41 L. The sampling rate was 0.1L/min and the average mass of formaldehyde collected was 250 ug.
2.5 Desorption Efficiency: No desorption efficiency corrections are necessary to compute air sample results because analytical standards are prepared using coated adsorbent. Desorption efficiencies were determined, however, to investigate the recoveries of the analytes from the sampling device. The average recovery over the range of 0.4 to 2 times the target concentration, based on the recommended air volumes, was 96.2% for formaldehyde. Desorption efficiencies were essentially constant over the ranges studied.
2.6 Recommended Air Volume and Sampling Rate:
2.6.1 The recommended air volume for formaldehyde is 24 L.
2.6.2 The recommended sampling rate is 0.1L/min.
2.7 Interferences:
2.7.1 Any collected substance that is capable of reacting 2-HMP and thereby depleting the derivatizing agent is a potential interference. Chemicals which contain a carbonyl group, such as acetone, may be capable of reacting with 2- HMP.
2.7.2 There are no other known interferences to the sampling method.
2.8 Safety Precautions:
2.8.1 Attach the sampling equipment to the worker in such a manner that it will not interfere with work performance or safety.
2.8.2 Follow all safety practices that apply to the work area being sampled.
3. Analytical Procedure
3.1 Apparatus:
3.1.1 A gas chromatograph (GC), equipped with a nitrogen selective detector. A Hewlett-Packard Model 5840A GC fitted with a nitrogen- phosphorus flame ionization detector (NPD) was used for this evaluation. Injections were performed using a Hewlett-Packard Model 7671A automatic sampler.
3.1.2 A GC column capable of resolving the analytes from any interference. A 6 ft x 1/4 in OD (2mm ID) glass GC column containing 10% UCON 50-HB-5100 + 2% KOH on 80/100 mesh Chromosorb W-AW was used for the evaluation. Injections were performed on-column.
3.1.3 Vials, glass 2-mL with Teflon-lined caps.
3.1.4 Volumetric flasks, pipets, and syringes for preparing standards, making dilutions, and performing injections.
3.2 Reagents:
3.2.1 Toluene and dimethylformamide. Burdick and Jackson solvents were used in this evaluation.
3.2.2 Helium, hydrogen, and air, GC grade.
3.2.3 Formaldehyde, 37% by weight, in water. Aldrich Chemical, ACS Reagent Grade formaldehyde was used in this evaluation.
3.2.4 Amberlite XAD-2 adsorbent coated with 2-(hydrosymethyl-piperidine (2- HMP), 10% by weight (section 4).
3.2.5 Desorbing solution with internal standard. This solution was prepared by adding 20 uL of dimethylformamide to 100 mL of toluene.
3.3 Standards preparation:
3.3.1 Formaldehyde: Prepare stock standards by diluting known volumes of 37% formaldehyde solution with methanol. A procedure to determine the formaldehyde content of these standards is presented in section 4. A standard containing 7.7 mg/mL formaldehyde was prepared by diluting 1 mL of the 37% reagent to 50 mL with methanol.
3.3.2 It is recommended that analytical standards be prepared about 16 hours before the air samples are to be analyzed in order to ensure the complete reaction of the analytes with 2-HMP. However, rate studies have shown the reaction to be greater than 95% complete after 4 hours. Therefore, one or two standards can be analyzed after this reduced time if sample results are outside the concentration range of the prepared standards.
3.3.3 Place 150-mg portions of coated XAD-2 adsorbent, from the same lot number as used to collect the air samples, into each of several glass 2-mL vials. Seal each vial with a Teflon-lined cap.
3.3.4 Prepare fresh analytical standards each day by injecting appropriate amounts of the diluted analyte directly onto 150-mg portions of coated adsorbent. It is permissible to inject both acrolein and formaldehyde on the same adsorbent portion. Allow the standards to stand at room temperature. A standard, approximately the target levels, was prepared by injecting 11 uL of the acrolein and 12 uL of the formaldehyde stock standards onto a single coated XAD-2 adsorbent portion.
3.3.5 Prepare a sufficient number of standards to generate the calibration curves. Analytical standard concentrations should bracket sample concentrations. Thus, if samples are not in the concentration range of the prepared standards, additional standards must be prepared to determine detector response.
3.3.7 Desorb the standards in the same manner as the samples following the 16- hour reaction time.
3.4 Sample preparation:
3.4.1 Transfer the 150-mg section of the sampling tube to a 2-mL vial. Place the 75-mg section in a separate vial. If the glass wool plugs contain a significant number of adsorbent beads, place them with the appropriate sampling tube section. Discard the glass wool plugs if they do not contain a significant number of adsorbent beads.
3.4.2 Add 1 mL of desorbing solution to each vial.
3.4.3 Seal the vials with Teflon-lined caps and then allow them to desorb for one hour. Shake the vials by hand with vigorous force several times during the desorption time.
3.4.4 Save the used sampling tubes to be cleaned and recycled.
3.5 Analysis:
3.5.1 GC Conditions Column Temperature:
Bi-level temperature program-First level: 100 to 1405 degrees C at 45 degrees C/min following completion of the first level.
Second level: 140 to 180 degrees C at 20 degrees C/min following completion of the first level.
Isothermal period: Hold column at 180 degrees C until the recorder pen returns to baseline (usually about 25 min after injection).
Injector temperature: 180 degrees C
Helium flow rate: 30 mL/min (detector response will be reduced if nitrogen is substituted for helium carrier gas).
Injection volume: 0.8 uL GC column: Six-ft x 1/4-in OD (2 mm ID) glass
GC column containing 10% UCON 50-HB-5100-2% KOH on 80/100 Chromosorb W-AW.
NPD conditions:
Hydrogen flow rate: 3 mL/min
Air flow rate: 50 mL/min
Detector temperature: 275 degrees C
3.5.2 Chromatogram: For an example of a typical chromatogram, see Figure 4.11 in OSHA Method 52.
3.5.3 Use a suitable method, such as electronic integration, to measure detector response.
3.5.4 Use an internal standard method to prepare the calibration curve with several standard solutions of different concentrations. Prepare the calibration curve daily. Program the integrator to report results in ug/mL.
3.5.5 Bracket sample concentrations with standards.
3.6 Interferences (Analytical).
3.6.1 Any compound with the same general retention time as the analytes and which also gives a detector response is a potential interference. Possible interferences should be reported to the laboratory with submitted samples by the industrial hygienist.
3.6.2 GC parameters (temperature, column, etc.) may be changed to circumvent interferences.
3.6.3 A useful means of structure designation is GC/MS. It is recommended this procedure be used to confirm samples whenever possible.
3.6.4 The coated adsorbent usually contains a very small amount of residual formaldehyde derivative (section 4.8).
3.7 Calculations:
3.7.1 Results are obtained by use of calibration curves. Calibration curves are prepared by plotting detector response against concentration for each standard. The best line through the data points is determined by curve fitting.
3.7.2 The concentration in ug/mL for a particular sample is determined by comparing its detector response to the calibration curve. If either of the analytes is found on the backup section, itis added to the amount found on the front section. Blank corrections should be performed before adding the results together.
3.7.3 The acrolein and/or formaldehyde air concentration can be expressed using the following equation:
mg/m [FN3] = (A) (B)/C
where A = ug/mL from 3.7.2, B = desorption volume, and C = L of air sampled.
No desorption efficiency corrections are required.
3.7.4 The following equation can be used to convert result in mg/m [FN3] to ppm. ppm = (mg/m [FN3]) (24.45)/MW
where mg/m [FN3] = result from 3.7.3, 24.45 = molar volume of an ideal gas at 760 mm Hg and 25 degrees C, MW = molecular weight (30.0).
4. Backup Data
4.1 Backup data on detection limits, reliable quantitation limits, sensitivity and precision of the analytical method, breakthrough, desorption efficiency, storage, reproducibility, and generation of test atmospheres are available in OSHA Method 52, developed by the Organics Methods Evaluation Branch, OSHA Analytical Laboratory, Salt Lake City, Utah.
4.2 Procedure to Coat XAD-2 Adsorbent with 2-HMP:
4.2.1 Apparatus: Soxhlet extraction apparatus, rotary evaporation apparatus, vacuum desiccator, 1-L vacuum flask, 1-L round-bottomed evaporative flask, 1-L Erlenmeyer flask, 250-mL Buchner funnel with a coarse fritted disc, etc.
4.2.2 Reagents:
4.2.2.1 Methanol, isooctane, and toluene.
4.2.2.2-(Hydroxymethyl) piperidine.
4.2.2.3 Amberlite XAD-2 non-ionic polymeric adsorbent, 20 to 60 mesh, Aldrich Chemical XAD-2 was used in this evaluation.
4.2.3 Procedure: Weigh 125 g of crude XAD-2 adsorbent into a 1-L Erlenmeyer flask. Add about 200 mL of water to the flask and then swirl the mixture to wash the adsorbent. Discard any adsorbent that floats to the top of the water and then filter the mixture using a fritted Buchner funnel. Air dry the adsorbent for 2 minutes. Transfer the adsorbent back to the Erlenmeyer flask and then add about 200 mL of methanol to the flask. Swirl and then filter the mixture as before. Transfer the washed adsorbent to a 1-L round-bottomed evaporative flask, add 13 g of 2-HMP and then 200 mL of methanol, swirl the mixture and then allow it to stand for one hour. Remove the methanol at about 405C and reduced pressure using a rotary evaporation apparatus. Transfer the coated adsorbent to a suitable container and store it in a vacuum desiccator at room temperature overnight. Transfer the coated adsorbent to a Soxhlet extractor and then extract the material with toluene for about 24 hours. Discard the contaminated toluene, add methanol in its place, and then continue the Soxhlet extraction for an additional 4 hours. Transfer the adsorbent to a weighted 1-L round-bottom evaporative flask and remove the methanol using the rotary evaporation apparatus. Determine the weight of the adsorbent and then add an amount of 2-HMP, which is 10% by weight of the adsorbent. Add 200 mL of methanol and then swirl the mixture. Allow the mixture to stand for one hour. Remove the methanol by rotary evaporation. Transfer the coated adsorbent to a suitable container and store it in a vacuum desiccator until all traces of solvents are gone. Typically, this will take 2-3 days. The coated adsorbent should be protected from contamination. XAD-2 adsorbent treated in this manner will probably not contain residual acrolein derivative. However, this adsorbent will often contain residual formaldehyde derivative levels of about 0.1 ug per 150 mg of adsorbent. If the blank values for a batch of coated adsorbent are too high, then the batch should be returned to the Soxhlet extractor, extracted with toluene again, and then recoated. This process can be repeated until the desired blank levels are attained.
The coated adsorbent is now ready to be packed into sampling tubes. The sampling tubes should be stored in a sealed container to prevent contamination. Sampling tubes should be stored in the dark at room temperature. The sampling tubes should be segregated by coated adsorbent lot number. A sufficient amount of each lot number of coated adsorbent should be retained to prepare analytical standards for use with air samples from that lot number.
4.3 A Procedure to Determine Formaldehyde by Acid Titration: Standardize the 0.1 N HC1 solution using sodium carbonate and methyl orange indicator.
Place 50 mL of 0.1 M sodium sulfite and three drops of thymophthalein indicator into a 250-mL Erlenmeyer flask. Titrate the contents of the flask to a colorless endpoint with 0.1 N HC1 (usually one or two drops is sufficient). Transfer 10 mL of the formaldehyde/methanol solution (prepared in 3.3.1) into the same flask and titrate the mixture with 0.1 N HC1. again, to a colorless endpoint. The formaldehyde concentration of the standard may be calculated by the following equation:

Formal- acid titer x acid
dehyde, = normality x 30.0
mg/mL mL of sample


This method is based on the quantitative liberation of sodium hydroxide when formaldehyde reacts with sodium sulfite to form the formaldehyde-bisulfite addition product. The volume of sample may be varied depending on the formaldehyde content but the solution to be titrated must contain excess sodium sulfite. Formaldehyde solutions containing substantial amounts of acid or base must be neutralized before analysis.






Appendix C. to Section 5217
Medical Surveillance -Formaldehyde

I. Health Hazards
The occupational health hazards of formaldehyde are primarily due to its toxic effects after inhalation, after direct contact with the skin or eyes by formaldehyde in liquid or vapor form, and after ingestion.
II. Toxicology
A. Acute Effects of Exposure
1. Inhalation (breathing): Formaldehyde is highly irritating to the upper airways. The concentration of formaldehyde that is immediately dangerous to life and health is 100 ppm. Concentrations above 50 ppm can cause severe pulmonary reactions within minutes. These include pulmonary edema, pneumonia, and bronchial irritation which can result in death. Concentrations above 5 ppm readily cause lower airway irritation characterized by cough, chest tightness, and wheezing. There is some controversy regarding whether formaldehyde gas is a pulmonary sensitzer which can cause occupational asthma in a previously normal individual. Formaldehyde can produce symptoms of bronchial asthma in humans. The mechanism may be either sensitization of the individual by exposure to formaldehyde or direct irritation by formaldehyde in persons with pre-existing asthma. Upper airway irritation is the most common respiratory effect reported by workers and can occur over a wide range of concentrations, most frequently above 1 ppm. However, airway irritation has occurred in some workers with exposures to formaldehyde as low as 0.1 ppm. Symptoms of upper airway irritation include dry or sore throat, itching and burning sensations of the nose, and nasal congestion. Tolerance to this level of exposure may develop within 1-2 hours. This tolerance can permit workers remaining in an environment of gradually increasing formaldehyde concentrations to be unaware of their increasingly hazardous exposure.
2. Eye contact: Concentrations of formaldehyde between 0.05 ppm and 0.5 ppm produce a sensation of irritation in the eyes with burning, itching, redness, and tearing. Increased rate of blinking and eye closure generally protects the eye from damage at these low levels, but these protective mechanisms may interfere with some workers' work abilities. Tolerance can occur in workers continuously exposed to concentrations of formaldehyde in this range. Accidental splash injuries of human eyes to aqueous solutions of formaldehyde (formalin) have resulted in a wide range of ocular injuries including corneal opacities and blindness. The severity of the reactions have been directly dependent on the concentration of formaldehyde in solution and the amount of time lapsed before emergency and medical intervention.
3. Skin contact: Exposure to formaldehyde solutions can cause irritation of the skin and allergic contact dermatitis. These skin diseases and disorders can occur at levels well below those encountered by many formaldehyde workers. Symptoms include erythema, edema, and vesiculation or hives. Exposure to liquid formalin or formaldehyde vapor can provoke skin reactions in sensitized individuals even when airborne concentrations of formaldehyde are well below 1 ppm.
4. Ingestion: Ingestion of as little as 30 ml of a 37 percent solution of formaldehyde (formalin) can result in death. Gastrointestinal toxicity after ingestion is most severe in the stomach and results in symptoms which can include nausea, vomiting, and severe abdominal pain. Diverse damage to other organ systems including the liver, kidney, spleen, pancreas, brain, and central nervous systems can occur from the acute response to ingestion of formaldehyde.
B. Chronic Effects of Exposure
Long term exposure to formaldehyde has been shown to be associated with an increased risk of cancer of the nose and accessory sinuses, nasopharyngeal and oropharyngeal cancer, and lung cancer in humans. Animal experiments provide conclusive evidence of a casual relationship between nasal cancer in rats and formaldehyde exposure. Concordant evidence of carcinogenicity includes DNA binding, genotoxicity in short-term tests, and cytotoxic changes in the cells of the target organ suggesting both preneoplastic changes and a doserate effect. Formaldehyde is a complete carcinogen and appears to exert an effect on at least two stages of the carcinogenic process.
III. Surveillance considerations
A. History
1. Medical and occupational history: Along with its acute irritative effects, formaldehyde can cause allergic sensitization and cancer. One of the goals of the work history should be to elicit information on any prior or additional exposure to formaldehyde in either the occupational or the non-occupational setting.
2. Respiratory history: As noted above, formaldehyde has recognized properties as an airway irritant and has been reported by some authors as a cause of occupational asthma. In addition, formaldehyde has been associated with cancer of the entire respiratory system of humans. For these reasons, it is appropriate to include a comprehensive review of the respiratory system in the medical history. Components of this history might include questions regarding dyspnea on exertion, shortness of breath, chronic airway complaints, hyperactive airway disease, rhinitis, bronchitis, bronchiolitis, asthma, emphysema, respiratory allergic reaction, or other preexisting pulmonary disease.
In addition, generalized airway hypersensitivity can result from exposures to a single sensitizing agent. The examiner should, therefore, elicit any prior history of exposure to pulmonary irritants and any short- or long-term effects of that exposure.
Smoking is known to decrease mucociliary clearance of materials deposited during respiration in the nose and upper airways. This may increase a worker's exposure to inhaled materials such as formaldehyde vapor. In addition, smoking is a potential confounding factor in the investigation of any chronic respiratory disease, including cancer. For these reasons, a complete smoking history should be obtained.
3. Skin Disorders: Because of the dermal irritant and sensitizing effects of formaldehyde, a history of skin disorders should be obtained. Such a history might include the existence of skin irritation, previously documented skin sensitivity, and other dermatologic disorders. Previous exposure to formaldehyde and other dermal sensitizers should be recorded.
4. History of atopic or allergic diseases: Since formaldehyde can cause allergic sensitization of the skin and airways, it might be useful to identify individuals with prior allergen sensitization. A history of atopic disease and allergies to formaldehyde or any other substances should also be obtained. It is not definitely known at this time whether atopic diseases and allergies to formaldehyde or any other substances should also be obtained. Also, it is not definitely known at this time whether atopic individuals have a greater propensity to develop formaldehyde sensitivity than the general population, but identification of these individuals may be useful for ongoing surveillance.
5. Use of disease questionnaires: Comparison of the results from previous years with present results provides the best method for detecting a general deterioration in health when toxic signs and symptoms are measured subjectively. In this way recall bias does not affect the results of the analysis. Consequently, OSHA has determined that the findings of the medical and work histories should be kept in a standardized form for comparison of the year-to-year results.
B. Physical Examination

1. Mucosa of eyes and airways: Because of the irritant effects of formaldehyde, the examining physician should be alert to evidence of this irritation. A speculum examination of the nasal mucosa may be helpful in assessing possible irritation and cytotoxic changes, as may be indirect inspection of the posterior pharynx by mirror.
2. Pulmonary system: A conventional respiratory examination, including inspection of the thorax and auscultation and percussion of the lung fields should be performed as part of the periodic medical examination. Although routine pulmonary function testing is only required by the standard once every year for persons who are exposed over the TWA concentration limit, these tests have an obvious value in investigation possible respiratory dysfunction andshould be used wherever deemed appropriate by the physician. In cases of alleged formaldehyde-induced airway disease, other possible causes of pulmonary disfunction (including exposures to other substances) should be ruled out. A chest radiograph may be useful in these circumstances. In cases of suspected airway hypersensitivity or allergy, it may be appropriate to use bronchial challenge testing with formaldehyde or methacholine to determine the nature of the disorder. Such testing should be performed by or under the supervision of a physician experienced in the procedures involved.

3. Skin: The physician should be alert to evidence of dermal irritation of sensitization, including reddening and inflammation, urticaria, blistering, scaling, formation of skin fissures, or other symptoms. Since the integrity of the skin barrier is compromised by other dermal disease, the presence of such disease should be noted. Skin sensitivity testing carries with it some risk of inducing sensitivity, and therefore, skin testing for formaldehyde sensitivity should not be used as a routine screening test. Sensitivity testing may be indicated in the investigation of a suspected existing sensitivity. Guidelines for such testing have been prepared by the North American Contact Dermatitis Group.
C. Additional Examinations or Tests
The physician may deem it necessary to perform other medical examinations or tests as indicated. The standard provides a mechanism whereby these additional investigations are covered under the standard for occupational exposure to formaldehyde.
D. Emergencies

The examination of workers exposed in an emergency should be directed at the organ systems most likely to be affected. Much of the contents of the examination will be similar to the periodic examination unless the patient has received a severe acute exposure requiring immediate attention to prevent serious consequences. If a severe overexposure requiring medical intervention or hospitalization has occurred, the physician must be alert to the possibility of delayed symptoms. Follow-up nonroutine examinations may be necessary to assure the patient's well-being.
E. Employer Obligations
The employer is required to provide the physician with the following information: A copy of this standard and appendices A, C, D, and E; a description of the affected employee's duties as they relate to his or her exposure concentration; an estimate of the employee's exposure including duration (e.g. 15 hr/wk, three 8-hour shifts, full-time); a description of any personal protective equipment, including respirators, used by the employee; and the results of any previous medical determinations for the affected employee related to formaldehyde exposure to the extent that this information is within the employer's control.

F. Physician's Obligations
The standard requires the employer to obtain a written statement from the physician. This statement must contain the physician's opinion as to whether the employee has any medical condition which would place him or her at increased risk of impaired health from exposure to formaldehyde or use of respirators, as appropriate. The physician must also state his opinion regarding any restrictions that should be placed on the employee's exposure to formaldehyde or upon the use of protective clothing or equipment such as respirators. If the employee wears a respirator as a result of his or her exposure to formaldehyde, the physician's opinion must also contain statement regarding the suitability of the employee to wear the type of respirator assigned. Finally, the physician must inform the employer that the employee has been told the results of the medical examination and of any medical conditions which require further explanation or treatment. This written opinion is not to contain any information on specific findings or diagnoses unrelated to occupational exposure to formaldehyde.
The purpose in requiring the examining physician to supply the employer with a written opinion is to provide the employer with a medical basis to assist the employer in placing employees initially, in assuring that their health is not being impaired by formaldehyde, and to assess the employee's ability to use any required protective equipment.






Appendix D. to Section 5217






Appendix E. to Section 5217
Qualitative and Quantitative Fit Testing Procedures

[See Section 5144, Appendix A]







s 5218. Benzene.
(a) Scope and Application.
(1) This section applies to all occupational exposures to benzene, Chemical Abstracts Service Registry No. 71-43-2, except as provided in subsections (a)(2) and (a)(3).

(2) This section does not apply to:
(A) The storage, transportation, distribution, dispensing, sale or use of gasoline, motor fuels, or other fuels containing benzene subsequent to their final discharge from bulk wholesale storage facilities, except that operations where gasoline or motor fuels are dispensed for more than 4 hours per day in an indoor location are covered by this section.
(B) Loading and unloading operations at bulk wholesale storage facilities which use vapor control systems for all loading and unloading operations, except for the provisions of section 5194, Hazard Communication, as incorporated into this section and the emergency provisions of subsections (g) and (i)(4) of this section.
(C) The storage, transportation, distribution or sale of benzene or liquid mixtures containing more than 0.1 percent benzene in intact containers or in transportation pipelines while sealed in such a manner as to contain benzene vapors or liquid, except for the provisions of section 5194, Hazard Communication, as incorporated into this section and the emergency provisions of subsections (g) and (i)(4) of this section.

(D) Containers and pipelines carrying mixtures with less than 0.1 percent benzene and natural gas processing plants processing gas with less than 0.1 percent benzene.
(E) Work operations where the only exposure to benzene is from liquid mixtures containing 0.1 percent or less of benzene by volume, or the vapors released from such liquids.
(F) Tire building machine operators except that such operators using solvents with more than 0.1 percent benzene are covered by subsection (i) of this section.
(G) Oil and gas drilling, production and servicing operations.
(H) Coke oven batteries.
(3) The cleaning and repair of barges and tankers which have contained benzene are excluded from subsections (f), methods of compliance; (e)(1), exposure monitoring-general; and (e)(6), accuracy of monitoring. Engineering and work practice controls shall be used to keep exposures below 10 ppm unless proven to not be feasible.
(b) Definitions.
"Action level." A concentration of airborne benzene of 0.5 ppm calculated as an 8-hour time-weighted average.
"Authorized person." Any person specifically authorized by the employer whose duties require the person to enter a regulated area, or any person entering such an area as a designated representative of employees for the purpose of exercising the right to observe monitoring and measuring procedures under subsection (1).
"Benzene." A chemical with the empirical formula, C6H 6, and Chemical Abstracts Service Registry No.71-43-2. For the purposes of this section, it includes both liquefied and gaseous forms of benzene; benzene contained in liquid mixtures; and the benzene vapors released from such mixtures. It does not include trace amounts of unreacted benzene in solid materials.
"Bulk wholesale storage facility." A bulk terminal or bulk plant where fuel is stored prior to its delivery to wholesale customers.
"Chief." The chief administrative officer of the Division of Occupational Safety and Health, P.O. Box 420603, San Francisco, CA 94142.
"Container." Any barrel, bottle, can, cylinder, drum, reaction vessel, storage tank, or the like, but does not include piping systems.
"Day." Any part of a calendar day.
"Director." The Director of the National Institute for Occupational Safety and Health, U.S. Department of Health and Human Services, or designee.
"Emergency." Any occurrence such as, but not limited to, equipment failure, rupture of containers, or failure of control equipment which may or does result in an unexpected significant release of benzene.
"Employee exposure." Exposure to airborne benzene which would occur if the employee were not using respiratory protective equipment.
"Regulated area." Any area where concentrations of airborne benzene exceed or can reasonably be expected to exceed, the allowable employee exposure limits, either the 8-hour time-weighted average exposure limit of 1 ppm or the short-term exposure limit of 5 ppm as averaged over a sampling period of 15 minutes.
"Vapor control system." Any equipment used for containing the total vapors displaced during the loading of gasoline, motor fuel or other fuel tank trucks and the displacing of these vapors through a vapor processing system or balancing the vapor with the storage tank. This equipment also includes systems containing the vapors displaced from the storage tank during the unloading of the tank truck which balance the vapors back to the tank truck.
(c) Employee Exposure Limits.
(1) Permissible Exposure Limit (PEL). The employer shall assure that no employee is exposed to an 8-hour time-weighted average concentration of airborne benzene in excess of one part benzene per million parts of air (1 ppm).
(2) Short Term Exposure Limit (STEL). The employer shall assure that no employee is exposed to a concentration of airborne benzene in excess of five (5) ppm as averaged over a sampling period of fifteen (15) minutes.
(d) Regulated Areas.
(1) The employer shall establish a regulated area wherever the concentration of airborne benzene exceeds or can reasonably be expected to exceed either the PEL or the STEL.
(2) Access to regulated areas shall be limited to authorized persons.
(3) Regulated areas shall be demarcated from the rest of the workplace in any manner that minimizes the number of employees exposed to benzene within the regulated area.
(e) Exposure Monitoring.
(1) General.
(A) Determinations of employee exposure shall be made from breathing zone air samples that are representative of each employee's average exposure to airborne benzene.
(B) Representative 8-hour time-weighted average exposures shall be determined on the basis of one sample or samples representing the full shift exposure for each job classification in each work area.
(C) Determinations of compliance with the STEL shall be made from 15-minute employee breathing zone samples measured at operations where there is reason to believe exposures are high, such as where tanks are opened, filled, unloaded or gauged; where containers or process equipment are opened and where benzene is used for cleaning or as a solvent in an uncontrolled situation. The employer may use objective data, such as measurements from brief period measuring devices, to determine where STEL monitoring is needed.
(D) Except for initial monitoring as required under subsection (e)(2), where the employer can document that one shift with consistently have higher employee exposures for an operation, the employer shall only be required to determine representative employee exposure for that operation during the shift on which the highest exposure is expected.
(2) Initial Monitoring.
(A) Each employer who has a place of employment covered under subsection (a)(1) shall monitor each of these workplaces and work operations to determine accurately the concentrations of airborne benzene to which employees may be exposed.
(B) The initial monitoring required under subsection (a)(2)(A) shall be completed within 30 days of the introduction of benzene into the workplace.
(C) Where the employer has previously monitored and the monitoring satisfies all other requirements of this section, the employer may rely on such earlier monitoring results to satisfy the requirements of subsection (e)(2)(A).
(3) Periodic Monitoring and Monitoring Frequency.
(A) If the monitoring required by subsection (e)(2)(A) reveals employee exposure at or above the action level but at or below the PEL, the employer shall repeat such monitoring for each such employee at least every year.
(B) If the monitoring required by subsection (e)(2)(A) reveals employee exposure above the PEL, the employer shall repeat such monitoring for each such employee at least every six (6) months.
(C) The employer may alter the monitoring schedule from every six (6) months to annually for any employee for whom two consecutive measurements taken at least 7 days apart indicate that the employee exposure has decreased to the PEL or below, but is at or above the action level.
(D) Monitoring for compliance with the STEL shall be repeated as necessary to evaluate exposures of employees subject to short term exposures.
(4) Termination of Monitoring.
(A) If the initial monitoring required by subsection (e)(2)(A) reveals employee exposure to be below the action level, the employer may discontinue the monitoring for that employee except as otherwise required by subsection (e)(5).
(B) If the periodic monitoring required by subsection (e)(3) reveals that employee exposures, as indicated by at least two consecutive measurements taken at least 7 days apart, are below the action level, the employer may discontinue the monitoring for that employee, except as otherwise required by subsection (e)(5).
(5) Additional Monitoring. (continued)