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Recommendations for Chemical Protective ClothingA Companion to the |
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Recommendations for Chemical Protective ClothingA Companion to the |
Recommendations for Chemical Protective Clothing
There are many chemicals which can cause adverse effects on unprotected skin ranging from contact dermatitis to permeation of the skin and systemic toxic effects. In addition, some chemicals (mostly solids) can present a contamination problem where inadvertent ingestion (e.g., lead) could occur or re-entrainment in the airstream (e.g., asbestos) could lead to inhalation. Chemical protective clothing (CPC), comprising gloves, boots, suits and other related components, can prevent direct skin contact and contamination. CPC can also prevent physical injury to the unprotected skin from thermal hazards such as from rapidly evaporating liquidified gases freezing the skin (e.g., LPG).
This report provides CPC recommendations for the chemicals listed in the NIOSH Pocket Guide to Chemical Hazards, June 1997 Edition (Publication No. 97-140). These recommendations are based on another published work, Quick Selection Guide to Chemical Protective Clothing, Third Edition, by Krister Forsberg and S.Z. Mansdorf (1997).
The Pocket Guide provides general recommendations for skin protection according to the following designations:
For the purposes of this report, the definitions of these designations are slightly different than those published in the Pocket Guide.
The "prevent skin contact" designation means that there is a dermal hazard potential. For work situations where direct contact could occur, it is recommendation that CPC providing resistance to permeation, penetration and degradation be used where the chemical has a potential to contact unprotected skin. A standard test method for permeation resistance has been devised by the American Society for Testing and Materials (ASTM) titled, Test Method for Resistance of Protective Clothing Materials to Permeation by Liquids or Gases Under Conditions of Continuous Contact (method F739-91). This test determines both the breakthrough time and steady state permeation rate of chemicals through a sample of the protective barrier. All chemicals will eventually permeate protective clothing. Breakthrough (permeation) resistance is related to temperature of the challenge material and the environment and thickness of the barrier. Therefore, higher than normal (25°C) temperatures will result in faster breakthrough. Use of thicker materials will increase time to breakthrough of the chemical.
The ASTM method establishes the time to breakthrough under conditions of continuous liquid or gaseous contact. Hence, a breakthrough time reported as 4 hours means four hours of resistance to permeation at detection levels generally above one-tenth microgram per square centimeter per minute (0.1 µg/cm2/min) at standard temperature conditions. Published breakthough data from academic institutions, research organizations, trade associations, chemical manufactures, protective clothing manufacturers and others can be used to select protective clothing in conjunction with other considerations. Not all chemicals nor barriers have been tested and the results published. For some chemicals listed in the Pocket Guide, no information is available. For many of the solids, such as pesticides. the proper selection of protective clothing depends on the exact solvent system and formulation hence for many no recommendations are made. Additionally, new barriers, barriers that have not been considered, or new testing may result in recommendations different from those listed in this report. Therefore, both the chemical and the protective clothing supplier should be contacted for the most appropriate choice before any final selection is made.
The "prevent skin contact" designation will also be found for materials that are solids (e.g., dust, powder, flakes, fibers, etc.). This designation is meant to alert the reader to inadvertent contamination of the skin resulting in the potential for later ingestion or inhalation but no significant dermal hazard. It is recommended that these chemicals not be allowed to contact the skin to prevent cross contamination. As a dry solid, there is no permeation potential- only a penetration potential through holes, tears, loose weaves, etc. for natural fibers and polymers. Therefore, any barrier which will prevent penetration may be used for the dry chemical provided that the dry solid is not placed into solution.
The "frostbite" designation is meant to alert the reader to the potential for freezing of the skin from direct contact with the liquidified gas through rapid evaporation. Some liquified gases may also present a direct skin hazard or a toxic hazard. For example, chlorine as a liquidified gas is corrosive, especially to wet skin, while hydrogen cyanide as a liquidified gas can permeate the skin leading to serious injury or death.
The "N.R." designation means that no recommendation can be made either because the chemical has not been shown to be a dermal hazard or inadequate information is available. Cellulose, for example, would not be expected to present a problem under normal circumstances. Nevertheless, each situation should be evaluated by a competent industrial hygienist or safety professional to determine whether protective clothing should be used.
Recommendations for skin protection and CPC are provided in the tables below. The chemicals and their corresponding Chemical Abstract Service (CAS) numbers are listed in the same order as they appear in the Pocket Guide. A list of abbreviations and explanations follow the table.
This Report was prepared by:
NTIS No. PB98-137730
February 1998
