Overview

Introduction

This document summarizes exposure data collected by OSHA between mid-September and mid-December 2005, in the region impacted by hurricanes Katrina, Rita, and Wilma. Response and recovery operations occurred over a large physical area and encompassed a wide range of specific activities and operations. OSHA collected exposure data for a limited subset of these operations, specifically those performed regularly during the period covered by this summary:

• Debris reduction, recycling, and disposal*
• Tree trimming
• Restoring electrical utilities
• Locating and establishing temporary housing facilities
• Building demolition
• Sand/sludge removal
• Roof inspection, tarping, and repair
• Assessment, cleanup, and repair of structures
• Roadway and bridge inspection and repair

* Although all the listed operations occurred regularly during this period, debris reduction, recycling, and disposal were the most prominent tasks and, therefore, were the activities where OSHA most frequently evaluated worker exposures.

Operations conducted during the initial response, such as floodwater removal and search and rescue, are not represented in the data summarized here. Nor does this summary include operations that had not begun as of mid-December 2005, such as large-scale demolition of homes and structures, including those built with asbestos-containing materials.

Limitations and Disclaimer

The Matrix does not provide an in-depth analysis of OSHA standards and regulations and cannot address all hazards. It does not increase or diminish any OSHA requirement or employer obligation under those requirements. It is intended as a guide and quick reference for employers and response and recovery workers. The Matrix captures major activities involved in hurricane response and recovery, highlights many of the hazards associated with them, and recommends "best practices." Employers must evaluate the specific hazards associated with the job/operation at the site where the work is being performed.

Employers are responsible for providing a safe and healthful workplace for their workers. OSHA's role is to assure the safety and health of America's workers by setting and enforcing standards; providing training, outreach, and education; establishing partnerships; and encouraging continual improvement in workplace safety and health.

The Hazard Exposure and Risk Assessment Matrix for Hurricane Response and Recovery Work provides a general overview of particular topics related to current OSHA standards. It does not alter or determine compliance responsibilities in OSHA standards or the Occupational Safety and Health Act of 1970, or the equivalent State Plan standards and requirements. Because interpretations and enforcement policy may change over time, you should consult current OSHA/State Plan administrative interpretations and decisions by the Occupational Safety and Health Review Commission and the courts for additional guidance on OSHA compliance requirements. Employers should modify their procedures as appropriate when additional, relevant information becomes available.

Noise and Air Monitoring Data and Assumptions

OSHA monitored the exposures of hurricane response and recovery workers to a variety of hazards including noise, dust (particulates), silica, asbestos, gas and vapors, and metals. Sample results that were obtained over a period of less than 8 hours are extrapolated to provide an 8-hour time-weighted average (TWA) by assuming that the same level of exposure continued for the full 8-hour shift.

The exposure results obtained by OSHA suggest that during the period covered by this summary, hurricane response and recovery workers routinely experienced noise, dust, or silica exposure when they performed certain tasks such as debris collection, debris reduction, site clearing, and activities such as transportation restoration and the operation of equipment such as chippers, chain saws, industrial vacuums, heavy equipment, and related machinery.

Noise Exposure Results Summary

• Twenty percent of the 324 workers evaluated had noise exposure levels above OSHA's permissible exposure limit (PEL) of 90 decibels (dBA). Over 40 percent of the sampled workers were exposed to noise levels of 85 dBA or higher.
• Hazardous levels of noise exposure were particularly common among response and recovery workers involved in debris collection, debris reduction, site clearing, and transportation restoration activities. Some of the highest noise exposures (above the PEL of 90 dBA) were associated with operating heavy equipment, chippers, chain saws, and industrial vacuums. These overexposed workers must wear earplugs or earmuffs to help prevent hearing loss.
• When workers are exposed to hazardous levels of noise, employers must enroll the workers in a hearing conservation program, similar to the one outlined in 29 CFR 1910.95(c), OSHA's standard on occupational noise exposure.
• See detailed results of noise sampling.

Dust Exposure Results Summary

• Over 5 percent of all the 217 workers evaluated experienced dust exposure that exceeded the PEL, with another 10 percent at or above the action level (usually defined as half of an established occupational exposure level, such as the PEL).
• The results suggest that heavy equipment operators were the group most consistently exposed to high levels of dust. Among those operators evaluated, more than one-third were exposed above the action level for dust (usually defined as half of an established occupational exposure level, such as a PEL).
• Most of highest dust exposure levels were measured while collecting and reducing debris or clearing sites (including grading operations).
• Dust control methods should be used more frequently during the dusty tasks, such as operating chippers and heavy equipment.
• To suppress dust and reduce worker exposure, some employers moisten materials with a water mist, use climate-controlled or enclosed cabs, use tools equipped with suction ventilation or wetting mists to capture or suppress dust before it spreads, and have workers stand up-wind from the dust source whenever practical.
• See detailed results of dust/particulates sampling.

Silica Exposure Results Summary

• Air sampling results indicated that about 20 percent of the 276 workers sampled worked in an area where silica exposure levels exceeded the action level. Eleven percent were exposed above the OSHA PEL for crystalline silica.
  • Nearly two-thirds of the sawing/grinding machine operators evaluated were exposed to silica dust concentrations at or above the action level (usually defined as half of an established occupational exposure level, such as the PEL).
  • Results for the heavy equipment operators and chipping equipment operators who were sampled exceeded the silica PEL more frequently than other workers evaluated.
• Workers with elevated silica exposures were likely performing activities such as jack hammering or sawing road surfaces and building materials, moving and dumping dry concrete and brick rubble, or crushing silica containing debris under heavy equipment, generating silica containing dusts.
• The silica sample results are important because they represent airborne levels of respirable silica dust, particles that are too small to see but that can be breathed deeply and retained in the lungs.
• Dust control methods, such as spraying water or using vacuum equipment to suppress dust generation, are particularly important for protecting workers conducting dust-generating activities on silica-containing materials (e.g., concrete, brick, mortar, grout, stone, sand, and dried sludge containing sand).
• See detailed results of silica sampling.

Asbestos/Total Fibers Results Summary

• Results indicate that many types of fibers can be released during hurricane response and recovery activities.
• Mixed fibers, including fiber glass, mineral wool, man-made vitreous fibers, and synthetic fibers, were present in 94 percent of the 235 samples analyzed for total fiber content.
• Overall, results obtained by OSHA showed that individuals employed as heavy equipment operators, laborers, waste/debris collectors, and quality assurance inspections had the highest total fiber exposure levels. There is not, however, a specific OSHA exposure standard for total fibers.
• Although asbestos was found in less than 1 percent of the samples evaluated during this phase of hurricane response and recovery, the risk could be higher during later phases when more workers are involved in building demolition.
• Individuals must wear an appropriate respirator where asbestos or potential asbestos containing materials may be present and may be impacted by the operation until the risk of asbestos exposure has been evaluated.
• Where asbestos is present, a specially trained competent person, defined in 29 CFR 1926.1101, can assist the employer in selecting the controls (i.e., engineering controls, work practices, and PPE) necessary to reduce exposures and to protect workers.
• See detailed results of asbestos/total fiber sampling.

Gas and Vapor Results Summary

• Formaldehyde is a component of some building materials, such as certain plywood, carpet adhesive, and insulation sometimes used in the manufacture of pre-fabricated trailers.
  • Sampling results for formaldehyde exceeded the action level in nearly 20 percent of the 95 air samples OSHA obtained during this phase of hurricane response. Exposure levels for the individuals evaluated approached, but did not exceed OSHA's PEL.
  • The available data suggests that the workers most at risk of formaldehyde overexposure were truck drivers and others responsible for delivering and setting up prefabricated trailers.
• Carbon monoxide is a colorless and odorless gas released when gas flames, combustion engines, and fires do not burn efficiently. Possible sources of exposure include emergency power generators used in poorly ventilated areas and gas powered saws in need of service.
  • Carbon monoxide levels exceeded the action level in 17 percent of the 51 samples collected.
  • On-site support workers (e.g., inspectors, engineers) had the highest carbon monoxide exposure levels among the workers evaluated.
• The available 399 results for 23 other gases and vapors sampled were below the action level.
• See detailed results of gas and vapor sampling.

Metals Results Summary

• Exposure results indicate that the workers evaluated during the operations characterized during this phase of hurricane response and recovery were rarely exposed to hazardous levels of airborne metals (e.g., as metal dust or fumes).
• These results represent the sampled workers' exposure to one or more of the 15 different metals analyzed, including lead, zinc, copper, iron, nickel and cadmium.
• OSHA evaluated workers in a wide range of occupations, including heavy equipment operators, structural steel workers, welders and cutters, hazardous waste removal workers, and on-site support personnel. Metal was detected in only 3 percent of the air samples.
• Only one of the 1,240 results for metals exceeded the action level. That individual, exposed to copper fume, was involved in debris reduction activities. An exposure to copper fume could result from hot work, such as cutting and welding.
• No metal was detected in most (97 percent) of the air sample results that OSHA obtained.
• See detailed results of metal sampling.

Note: Cutting or burning on painted metal surfaces must always be evaluated for exposure to lead unless documentation exists that precludes its presence.

Background

What these sampling results represent

This document summarizes exposure results obtained by OSHA personnel between mid-September and mid-December of 2005 in the region impacted by hurricanes Katrina, Rita, and Wilma. The area of impact included Texas, Louisiana, Mississippi, Alabama, and Florida. Although the focus of both the response and recovery effort and the exposure data collection effort has been Mississippi and Louisiana, all available results from Texas, Alabama and Florida are also included in this summary. Response and recovery operations occurred over a large physical area and encompassed a wide range of specific activities and operations. Exposure data was collected for a limited subset of these operations.

Operations conducted between September and December 2005 included: utility restoration, debris collection and reduction, tree trimming, establishing temporary housing sites, demolishing buildings, sand and sludge removal, repairing and tarping roofs, community damage assessment, environmental assessment and cleanup, and road and bridge repair. During this time period, however, debris collection and reduction activities were the primary operations conducted and so they were also the activities most frequently characterized in the exposure monitoring data summarized here.

What these sampling results do not cover

Operations conducted during the initial response, such as floodwater removal, and search and rescue are not represented in the data summarized here. Nor does this summary include operations that had not begun as of mid-December 2005, such as large-scale demolition of homes and structures, including those built with asbestos-containing materials.

How sampling was conducted

OSHA sampled a large number of workers in a range of jobs to quickly identify the most serious health threats during response and recovery operations and to find out what types of exposures typically occur during these operations. In general, OSHA sampled the substances that response and recovery workers were most likely to encounter during the work they performed. The results of these samples will help create an historic database that can be used for future risk assessment. Employers may use this information to evaluate the level of hazard workers are likely to encounter when working under similar conditions after future hurricanes or related disasters.

OSHA collected air and noise samples to evaluate exposure to air contaminants and noise during numerous hurricane response and recovery activities. Except for the gas and vapor samples, most of the results summarized in this section were obtained using personal sampling methods. To obtain personal samples, individuals wore sampling devices during the period evaluated to collect air samples from their breathing zone or, in the case of noise samples, from near their ears. In addition to using personal sampling methods, some gas and vapor samples were collected using area sampling methods and using direct-reading instruments.

How samples were analyzed

Many types of air samples required laboratory analysis and were sent to OSHA's Salt Lake Technical Center laboratory, which is accredited by the American Industrial Hygiene Association (AIHA). The results of this analysis were recorded as the average exposure level for the time period that was sampled. Results for air samples obtained with calibrated direct-reading instruments (e.g., carbon monoxide) were recorded as the average exposure detected by the instrument during the period sampled. Noise samples, which are also obtained using direct reading instruments, were reported the same way.

How results were evaluated

The samples were collected during all or part of the workers' work shifts and represent their exposure during the period sampled. In evaluating the results of these samples, OSHA assumed that individuals experienced the same average exposure during any additional unsampled portions of their workshift. The results represent the 8-hour time-weighted-average (TWA) exposure levels that the workers would have experienced if they had continued the same tasks and used the same methods throughout an 8-hour shift. To determine whether an individual was overexposed to a substance or noise, OSHA compared the sample results to the:

• Permissible Exposure Limit (PEL). An worker is considered overexposed if the sample result exceeded the PEL for the hazard evaluated.

• Action Level (AL). If not otherwise established by a standard, the "action level" is usually defined as half of an established occupational exposure level. Although not overexposed, an worker is considered at risk of being overexposed if the result is between the AL and the PEL. In this case the employer should consider taking additional steps to ensure the worker exposure levels do not reach the PEL.

Detailed Results

Summary of Noise Sampling Results

OSHA measured noise exposure levels for workers performing various hurricane response and recovery tasks involving noisy activities or equipment. The 342 time-weighted average (TWA) personal noise exposure levels obtained by OSHA during this period indicate that many workers are regularly exposed to hazardous levels of noise.

As shown in Table II-1, the noise exposure levels for 20 percent of the 342 individuals sampled exceed OSHA's PEL of 90 decibels on an A-weighted-scale (dBA). Furthermore, when a subset of these workers was evaluated using a lower (i.e., 80 dBA) threshold, 41 percent were found to have experienced TWA noise levels of 85 dBA (the OSHA action level) or higher.

This value of 85 dBA is important because when exposure levels reach or exceed an average level of 85 dBA as an 8-hour TWA, workers should have employer-provided hearing protection made available and be placed in a hearing conservation program to minimize the chance of noise-induced hearing loss. A hearing conservation program should include noise exposure monitoring, routine medical evaluations (hearing tests), and training on noise and its effects. General industry employers are required to take these steps when exposures are at or above 85dBA.

Analysis of the noise sampling results show that the response and recovery workers most likely to be exposed to hazardous levels of noise (over 90 dBA) include those involved in:

• Debris removal
• Debris reduction
• Site clearing
• Transportation restoration activities

In particular, those at greatest risk for overexposure to noise include:

• Workers working with chippers, chain saws, industrial vacuums, heavy equipment, or other noisy machinery
• Laborers
• Waste/debris collectors
• Structural iron and steel workers

Sample results show that individuals performing these jobs, as well as truck drivers, flaggers/spotters, and others who spend a significant amount of time in the immediate vicinity of noisy operations, may be exposed to noise levels above 90 dBA. Provide hearing protection and training, and enroll workers in a hearing conservation program. For general industry employers, these actions are required when noise exposures exceed 85dBA.

Workers are less likely to experience hazardous noise exposure levels if they do not operate noisy equipment themselves, or if their jobs allow them to move away from noisy equipment or to less noisy locations. The available results suggest that some job categories, such as utility workers and support personnel, were less likely to expose the worker to hazardous levels of noise for extended periods.

Users are cautioned, however that each work situation is different. Regardless of an individual's activities, if conditions are noisy enough that workers separated by an arm's length (approximately three feet) must raise their voices to have a conversation, they are probably exposed to 85 dBA or greater. If that level of noise continues for most of the work shift, the worker will likely be exposed to a level of at least 85 dBA unless testing proves otherwise.

Summary of Dust/Particulates Sampling Results

OSHA evaluated airborne concentrations of dust (also called particulates) in the breathing zone of 294 hurricane response and recovery workers during this period. These samples provided 217 results for total dust and 77 results for the smaller respirable dust particles (the respirable fraction). As shown in Figure II-A and Table II-2:

• Analysis of the total dust samples indicate that six percent of the individuals sampled exceeded the PEL (15 milligrams per cubic meter (mg/m³), while another 10 percent were exposed to concentrations above the action level (but below the PEL).
• The respirable dust sample results indicate that 4 percent of the individuals sampled exceeded the PEL (5 mg/m³), while another 4 percent had exposures that exceeded the action level.

The vast majority of the dust results that exceeded either the action level or the PEL were associated with:

• Debris collection/removal
• Debris reduction
• Site clearing/grading operations

However, not all jobs associated with this work resulted in notable dust exposure. The personal air sampling results for total and respirable dust were below the action level for the following occupation categories:

• Chain saw and sawing machine operators
• Welders
• Structural iron and steel workers
• Office personnel (e.g., administrators, secretaries) and on-site support personnel (e.g., engineers, inspectors, scientists, technicians, estimators)

Under the conditions sampled, results were below the action level even when these jobs were associated with debris removal and reduction or site clearing operations. In some cases, workers might have been protected by dust control methods such as standing upwind of dusty equipment, or using wet methods or exhaust ventilation for some tasks. For example, workers reduced airborne dust at some debris sites by using water spray to keep the roads and debris damp. Other workers, such as steel erectors, office personnel, and on-site support personnel might have worked at a distance from the source of the dust (or entered the dusty area only infrequently), so their average dust exposure was below the action level on the dates sampled. Finally, the amount of rainfall preceding sampling would directly impact the amount of ambient dust.

 

Summary of Silica Sampling Results

Response and recovery workers may be exposed to crystalline silica (called silica in this document) when they crush, grind, chip, or cut concrete, stone, brick, tile, or mortar. Individuals might also be exposed to this substance if they handle materials that release very fine silica particles (e.g., if they dump loads of materials such as dry sludge and construction debris that include dust from concrete or sand). In particular, silica exposure can occur when heavy traffic disturbs silica-containing road dust at hurricane debris sites. Silica exposure is also common where workers operate heavy equipment with open cabs (an enclosed cab can separate the worker from the dust source), or when workers do not use wet methods (such as water mist spray) to suppress dust.

Figure II-B present information on hurricane response and recovery worker exposure to silica. Overall the PEL was exceeded in 11 percent of the samples analyzed for silica. Another 9 percent of the results were at or above the action level, but did not exceed the PEL.

 

The percentage of workers exposed above the PEL was higher in areas where samples confirmed that airborne silica was present. Of the 276 personal breathing zone samples analyzed, 83 (30 percent) actually contained silica. However, among these 83 samples, results show that 30 percent of the workers sampled exceeded the PEL, while another 34 percent had exposures exceeded the action level.

All but one of the samples at or above the action level were associated with conducting debris collection, reduction, or demolition activities. The only exception was a sweeper working at a maritime port restoration site. These results indicate that dust control methods should be used more frequently during debris collection, reduction, and demolition, and other dusty tasks involving materials that are suspected of containing silica.

As shown in Figure II-C and Table II-3, heavy equipment operators and machine operators were most likely to experience notable silica exposure. Nearly two-thirds of machine operators sampled were exposed at or above the action level. Nearly one-quarter of heavy equipment operators sampled were exposed above the action level. These operators were likely performing activities such as jack hammering or sawing building materials or road surfaces, moving and dumping concrete and brick, or crushing silica-containing debris under heavy equipment that would produce silica-containing dusts.

Sample results for several work groups consistently indicated low concentrations of silica during this phase of hurricane response and recovery. Job groups for which all the available silica results were less than 50 percent of the PEL include waste collectors, truck drivers, and administrative personnel.

 

Summary of Asbestos and Total Fiber Sampling Results

Asbestos

Response and recovery workers in numerous jobs were sampled to determine their asbestos exposure levels. In particular, OSHA evaluated workers in jobs related to debris collection and reduction activities, such as heavy equipment operators, truck drivers, hazardous materials removal workers, and laborers. In all, OSHA obtained 221 personal air samples and 38 area samples (a total of 259 samples). A measurable amount of asbestos (also called a quantifiable level) was found in only two of the 259 samples collected and both of these results were less than one-tenth of the PEL of 0.1 fiber per cubic centimeter of air (f/cc). As shown in Figure II-D, this means that asbestos was found in 1 percent of the samples. The measurable amounts of asbestos were associated with laborers performing site-clearing operations. Although asbestos was not detected in air samples from the breathing zone of most workers during these first few months of hurricane response activity, individuals might encounter asbestos more frequently as demolition work increases in later phases of hurricane recovery.

Note: There are over 45, 000 structures slated for demolition in New Orleans. Approximately 90% of these structures were built before 1980, increasing the possibility that they contain Asbestos Containing Building Materials.

 

Regardless of the phase of hurricane response, employers need to take special steps to protect workers involved in demolition of buildings known to contain, or suspected of having asbestos in some of the building materials. Workers must also be protected when debris of those materials are collected, removed, or processed for disposal. Typical asbestos worker protection measures include:

• Evaluating work sites to determine whether asbestos is in the building materials
• Using only workers that are trained and equipped for handling asbestos
• Establishing restricted areas and erecting enclosures (where feasible) to prevent asbestos from spreading through the work area
• Wetting materials to keep fibers from becoming airborne
• Selecting appropriate personal protective equipment (PPE), including respirators
• Avoiding dumping asbestos-containing materials into dumpsters

A competent person, who is specially trained in safe asbestos removal and handling methods, can assist the employer in selecting the controls (i.e., engineering controls, work practices, and PPE) necessary to reduce exposures.

For additional information about asbestos at construction or demolition sites, see OSHA's Asbestos Safety and Health Topics page. OSHA's Asbestos Standard for construction is contained in 29 CFR 1926.1101.

Other Fibers

The analysis OSHA performed for asbestos also showed that other types of fibers were present in almost all the samples collected. Mixed fibers in workplaces typically include fiberglass, mineral wool, cellulose, man-made vitreous fibers, and synthetic fibers from fabrics. The combined result for asbestos and other fibers together is called the total fiber level. Mixed fiber types were detected in 222 of the 235 area and personal samples analyzed for total fibers (a subset of the samples analyzed for asbestos). As shown in figure II-E, this mixed fiber was present in 94 percent of the samples. These results suggest that fibers can become airborne during certain hurricane recovery tasks, so worker protection is important during jobs that involve handling fibrous materials (fiberglass, asbestos, etc). In particular, workers must wear an appropriate respirator until the risk of asbestos exposure has been determined through the identification of potential sources and through airborne exposure sampling.

Among the samples reviewed for this summary, the highest total fiber results were associated with those employed as heavy equipment operators, laborers, waste/debris collectors, and quality assurance inspectors.

 

Summary of Gas and Vapor Sampling Results

The available results for gas and vapor personal and area sampling showed that, during this initial phase of hurricane response and recovery, workers experienced exposure to measurable levels of some substances; however, their exposure to gases and vapors did not exceed the respective PELs for the substances sampled. OSHA obtained 545 air sample results for 25 different individual substances or groups of substances (see sidebar). Except for samples evaluating formaldehyde, most results were obtained using direct reading instruments and many represent area samples collected near the source of the gas or vapor.

Table II-5 provides a summary of the gases and vapors for which samples were collected and analyzed most frequently (i.e., more than 30 samples were collected for each). As indicated in Figure II-F, exposure levels at or above the action levels were found for formaldehyde and carbon monoxide only. All results for other gases or vapors were below the action level.

Formaldehyde is commonly used as a preservative and is an ingredient in the binding agent used to manufacture certain construction materials (e.g., some plywoods).

Carbon monoxide is a gas that can cause death within several minutes of exposure to high concentrations. The gas is a natural byproduct of combustion and is generated by gas flames, internal combustion engines (such as gasoline powered generators or motors), or fires. The hurricane response and recovery workers in the areas with the highest carbon monoxide exposure levels were on-site support workers conducting building inspections. In these cases, the carbon monoxide likely originated from generators, gas powered saws, and other internal combustion engines. Do not use this type of equipment in enclosed areas, where the toxic gas can build up. Where the possibility of carbon monoxide exposure exists, employers must conduct evaluations to determine if workers are being exposed to carbon monoxide at hazardous concentrations. Hand-held direct-reading instruments for measuring carbon monoxide are readily available from commercial sources.

Summary of Metal Sampling Results

The available exposure results for metals indicate that the evaluated workers rarely experienced significant exposure to metals during this phase of hurricane response and recovery activities. Overall, OSHA recorded air sampling results for 15 different metals (see sidebar). Because most workers did not work with a large number of different metals in a day, OSHA focused primarily on the metals associated with materials that the individual handled.

However, the standard analytical test methods used to measure certain metals also test for the presence of other metals at the same time. When tests provided results for additional metals, those additional results were included in this review. Altogether, OSHA obtained 1,240 results representing workers exposures to airborne metals, including metal fumes.

 

Table II-6 summarizes the air sampling results for some metals commonly found in construction materials.