Tiny troublemakers

  • Mar 01, 2000

Remediation projects, accident response and other pollution abatement activities can present work crews with all sorts of unpleasant surprises. Airborne particles from ruptured drums of chemical granules and broken bags of unknown powders are typical of the particle hazards that can be encountered. Considering the variety of airborne particles that might be accidentally released at an incident and during cleanup, it is important to ensure that workers are protected against the widest possible range of particles that could cause damage from inhalation or skin contact.

Personal protective equipment (PPE), which includes protective clothing, respiratory protection and other safety accessories, is recognized by industry as the last line of defense for workers in hazardous environments. While routine industrial hazards can often be mitigated through engineering or administrative changes — thus reducing the need for PPE — the uncertainty of exposures in pollution abatement situations places greater reliance on PPE for protecting the health of cleanup workers. For this reason, the selection and proper use of protective apparel should be given attention at all organizational levels — from top management to site supervisors to individual employees.

The Occupational Safety and Health Administration (OSHA) has set forth minimum requirements for the use of PPE in its General Requirements for Personal Protective Equipment for General Industry (29 Code of Federal Regulations (CFR) 1910.132).

In addition, Hazardous Waste Operations and Emergency Response (HAZWOPER) regulations (29 CFR 1910.120) apply to many, if not most, emergency response and remediation situations. As such, a written PPE program is required and must include:

  • PPE selection based on site hazards;

  • PPE use and limitations of the equipment;

  • Work mission duration;

  • PPE maintenance and storage;

  • PPE decontamination and disposal;

  • PPE training and proper fitting;

  • PPE donning and doffing procedures;

  • PPE inspection procedures prior to, during and after use;

  • Evaluation of the effectiveness of the PPE program; and

  • Limitations during temperature extremes, heat stress and other appropriate medical conditions.

These disciplined approaches have become the accepted practice in PPE selection. However, in these situations, the selection process is built on a thorough hazard assessment, which requires the employer to know the specific exposure risks and hazards that will be encountered by their employees.

While this type of assessment-based process can be useful in selecting PPE for pollution abatement workers, the uncertainty of the hazards involved in environmental cleanup means that high-quality protective gear is a "given" requirement, and that the PPE selected must be suitable for the hazards encountered. Furthermore, remediation crews, emergency response teams and other pollution-control organizations must be prepared to deal safely with an extremely wide range of potential hazards.

Hazardous particles: Particularly challenging

Providing personnel with proper protection from hazardous particles is especially challenging because of the many types of toxic materials that may be present in the air, and the different ways these agents can affect the human body. Asbestos fibers, rock dust, radioactive dust, carbon fiber, dry-mix agricultural chemicals and particle matter from heavy metals are just a few of the many hazardous particles that must be considered in selecting the proper PPE for environmental operations. Even wood dust, sugar particles and cotton fibers can present a hazard, in sufficiently high concentrations.

These tiny troublemakers gain access to the human body in a number of ways, including inhalation, ingestion and contact with exposed skin areas. Respirators can be used to provide primary protection against inhalation and ingestion hazards. High-quality protective apparel is required to create an effective dry-particle barrier that prevents contact with skin and hair, and avoids contamination of the worker's everyday clothing.

The "take-home" problem

Preventing skin contact with skin-toxic and reactive particles make sense. However, it may not be as obvious that preventing the contamination of skin, hair and street clothing can be equally important in protecting workers, and their families, from ingestion and inhalation hazards. Away from the job site, hazardous particles may still be shed by contaminated skin and hair, and inhaled by the worker. Showering is only partially effective in consistently removing all particle contamination. A study commissioned by DuPont showed that hair contaminated with asbestos must be vigorously washed to remove all the contaminates. This "take-home" problem has been well documented by the National Institute for Occupational Safety and Health (NIOSH), and is the reason why many protective clothing regulations and guides recommend the use of clean protective apparel, designated changing areas, field hygiene practices and other hygiene practices.

Hazardous particles can enter protective clothing in several ways, including direct penetration through the fiber, mechanical abrasion or "rub through," as well as through seams and joints in the garment. It is important to select high-quality protective apparel made from "high-barrier" fabric that can maintain integrity despite rough usage. This is especially important in environmental remediation work, because the wearer may be required to perform manual tasks in a variety of hazardous work environments.

To be effective in the widest range of situations, particle barrier clothing must provide protection against many different types, sizes and concentrations of particle matter.

The apparel must also be durable, flexible and comfortable for the wearer. High visibility is also a requirement of teams that may have to deal with emergency events at night. However, the most important criteria for selecting abatement apparel are garment design and barrier properties.

Establishing apparel standards

Guidelines and standards for selecting protective clothing are available from a number of sources. The OSHA technical manual describes considerations that should be included in selection, training and use. The selection of protective clothing and equipment is a fundamental part of the training and accreditation of certified industrial hygienists (CIHs) and certified safety professionals (CSPs). The text and reference sources utilized by these professions include detailed information on these subjects. In addition, appendix information in OSHA's PPE standards 29 CFR 1910, Subpart I, is helpful in selecting ensembles that will provide protection against particles.

In the publication Limits for Air Contaminants, (29 CFR 1910.1000) OSHA lists permissible exposure levels (PELs) for some of the most common airborne particles (see E-sources), and the American Conference of Governmental Industrial Hygienists (ACGIH) Handbook contains threshold limit values (TLVs) for a wide range of hazardous substances. These exposure limits can be useful in setting standards for protective clothing, breathing apparatus and other items in the PPE wardrobe.

Many companies routinely engaged in activities involving hazardous particles establish their own standards to protect employees. Firms in the mining, chemical, petrochemical and metalworking industries are among the pioneers in this area. DuPont, for example, sets allowable exposure levels (AELs) for a long list of hazardous particles and enforces these limits throughout its worldwide operations.

Testing apparel for performance

Although there is no industry-accepted method for testing particle penetration through protective clothing, DuPont has run controlled evaluations with a number of hazardous materials. The company's line of protective apparel made from Tyvek¨ spunbonded polyolefin has been tested and found effective against a number of particle challenges, including asbestos fibers, bacteria spores, di-octyl phthalate, microcrystalline silica and liquid-borne as well as ambient-air particles.

Wearer education and training are essential

As shown by the OSHA requirements in Table 1, educating cleanup crews is critical to worker health and safety in areas where hazardous particles may be present. Pollution abatement and remediation personnel should be educated in the hazards of particle exposure; types of particles most likely to be encountered; how to identify hazardous substances; how to don, doff and operate PPE components; proper sizing of garments; and methods of maintenance and safe disposal. In many cases, garments that have been worn in contact with hazardous particles, such as asbestos, cannot be reused because of the costs involved in decontamination. Employees may also have to be trained in special hygiene techniques so that they do not carry the particle contaminants with them when they leave the cleanup site.

Table 1

OSHA's requirements for personal protective equipment used by general industry:

  • Perform and document a hazard assessment.

  • Select appropriate PPE based on hazard assessment.

  • Communicate to employees.

  • Train employees:

  • When PPE is necessary;

  • What PPE is necessary;

  • How to don, doff and wear PPE; and

  • How to care for, maintain and dispose of PPE.

  • Verify and document that:

  • Employees understand training; and

  • Employees demonstrate proper use of PPE.

  • Retrain:

  • When PPE changes;

  • When hazard changes; and

  • When employee uses PPE improperly.

E-sources

OSHA permissible exposure levels for common airborne particles: www.osha-slc.gov/OshStd_toc/OSHA_Std_toc_1910_SUBPART_Z.html

American Conference of Governmental Industrial Hygienists, Inc. (ACGIH): www.acgih.org

National Fire Protection Association (NFPA): www.nfpa.org

American Society for Testing and Materials (ASTM): www.astm.org

DuPont protective apparel: www.duponttyvek.com/us/protective-apparel/English

Safety imperative for cleanup crews: Chemical protective clothing

A myriad of industrial chemicals travels the highways, waits in tank farms and storage areas, and flows through process pipelines. These include a wide range of acids, solvents, fuels, insecticides, paints, industrial wastes, compressed gases and specialized fluids used by medical institutions and the military. Chemicals of unknown origin — in buckets, drums and compressed gas cylinders — lie buried in both known and yet to be discovered locations. Pollution abatement and emergency response teams who have to deal with these situations require respiratory protection as well as chemical protective clothing (CPC) to isolate them from these potentially hazardous materials.

OSHA regulations, technical manuals and compliance directions provide direction on the selection of respiratory protection, protective clothing and other PPE, that may be needed in chemical exposure situations. Specifically, PPE regulations (29 CFR 1910, Subpart I) and Hazardous Waste Operations and Emergency Response regulations (HAZWOPER) (29 CFR 1910.120) are the first places to look. In addition, there are specific requirements for protective clothing and equipment in 29 CFR 1910, Subpart Z, related to specific chemical hazards (such as asbestos). Specific industry sections within the OSHA regulations, such as shipyard and construction, also contain requirements and guidance on protective clothing that may need to be considered in certain situations.

Chemical protective clothing and respiratory protection are the primary focus for PPE selection in the HAZWOPER, though protective equipment for face, head, hand and foot protection should not be neglected. In developing HAZWOPER, OSHA adopted a four-level description of CPC originally developed by U.S. EPA. These levels of protection are:

Level A — Worn when the highest level of skin, respiratory and eye protection against chemicals is required. Level A protective ensembles generally consist of totally encapsulating protective suits worn with a self-contained breathing apparatus (SCBA) or with airline and an escape bottle.

Level B — Worn when the highest level of respiratory protection is required, but a lesser level of skin protection is needed. Generally these Level B ensembles consist of a chemical liquid-splash protective suit worn with SCBA or with airline and escape bottle.

Level C — Worn when the identity and concentration of airborne particle, liquid or vapor challenges are known, and when an air-purifying respirator provides protection. Generally, Level C ensembles consist of a hooded particle and/or liquid protective, hooded coverall and a full- or half-face respirator.

Level D — Worn when the atmosphere contains no known hazard and the task precludes splashes, immersion, or the potential for unexpected inhalation of or contact with hazardous levels of any chemicals. A Level D ensemble provides minimal protection and is used for nuisance contamination only.

However, as pointed out in Appendix B of HAZWOPER, "Combinations of personal protective equipment other than those described for Levels A, B, C and D protection may be more appropriate and may be used to provide the proper level of protection."

Note:

This information is based on technical data that DuPont believes to be reliable. This information is subject to revision as additional knowledge and experience are gained. DuPont makes no warranties, express or implied, including without limitation, no warranties of merchantability or fitness for a particular use. DuPont assumes no obligation or liability whatsoever in connection with any use of the information contained in this article. This information is not intended as a license to operate under or a recommendation to infringe any patent or technical information of DuPont or others covering any material or its use.

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This article appeared in the March 2000 issue of Environmental Protection magazine, Vol. 11, No. 3, p. 52

This article originally appeared in the 03/01/2000 issue of Environmental Protection.

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