Methods: State-Based Surveillance
Cases of silicosis from state-based surveillance are confirmed based on the surveillance case definition for silicosis. The silicosis case definition includes 1) an occupational exposure history to airborne silica dust and 2) a positive chest radiograph or other imaging technique for silicosis and/or positive pathologic findings characteristics of silicosis. For more information, see Silicosis State Reporting Guidelines and Case Definition .
The year (time period) presented in the table is the year (time period) that the case was first reported to the state. This may or may not be the year of silicosis diagnosis, which may have been earlier.
State-based information is presented by case ascertainment source, duration of silica exposure, Workers' Compensation claim status, small and large opacity profusion categories, and by reported primary industries and occupations of the cases identified. See Industry/Occupation Codes and Titles section below for industry and occupation classifications.
Cases of work-related asthma (WRA) from state-based surveillance are grouped based on WRA classification criteria into two major types: 1) work-aggravated asthma (WAA) and 2) new-onset asthma (NOA). NOA is further classified as either reactive airways dysfunction syndrome (RADS) or occupational asthma (OA) and its sub-classifications. For more information, see Work-Related Asthma State Reporting Guidelines and Case Definition . In some instances WRA cases may meet the requirements of the surveillance case definition for a confirmed case of WRA without sufficient information for classification. These cases are noted as "Confirmed, but unclassified".
The year (time period) presented in the table is the year (time period) that the case was first reported to the state. This may or may not be the year of work-related asthma onset or diagnosis, which may have been earlier.
Information is also presented by Workers' Compensation claim status, and by reported primary industries and occupations. See Industry/Occupation Codes and Titles section below for industry and occupation classifications.
Putative agents associated with cases of WRA are grouped using established Association of Occupational and Environmental Clinics (AOEC) exposure categories and sub-categories 1 or combined individual exposure codes. The combined individual exposure codes contain agents of similar use or chemical nature. The following table shows the AOEC exposure categories and corresponding exposure code prefixes presented in the work-related asthma tables.
|Exposure Categories||Exposure Code Prefix||Year Posted (eWoRLD)|
|Mineral and inorganic dusts||010–012||2012, 2014, 2015|
|Metals and metalloids||020–024||2012, 2014, 2015|
|Halogens (inorganic)||030||2012, 2014, 2015|
|Miscellaneous inorganic compounds||040–042||2012, 2014, 2015|
|Acids, bases and oxidizing agents||050–052||2012, 2014, 2015|
|Aliphatic and alicyclic hydrocarbons||060–061||2012, 2014, 2015|
|Alcohols||070||2012, 2014, 2015|
|Glycols||080||2012, 2014, 2015|
|Glycol ethers||090–091||2012, 2014, 2015|
|Ethers||100||2012, 2014, 2015|
|Epoxy compounds||110||2012, 2014, 2015|
|Aldehydes and acetals||120||2012, 2015|
|Ketones||130||2012, 2014, 2015|
|Esters||140–142||2012, 2014, 2015|
|Aliphatic carboxylic acids||150–151||2012, 2014|
|Aliphatic carboxylic acids and anhydrides||150–151||2015|
|Aromatic hydrocarbons||160–161||2012, 2014|
|Hydrocarbons, n.o.s.||170||2012, 2014, 2015|
|Solvents, n.o.s.||171||2012, 2014, 2015|
|Phenols and phenolic compounds||180–181||2012, 2014, 2015|
|Halogenated aliphatic hydrocarbons||190–192||2012, 2014, 2015|
|Halogenated aromatic hydrocarbons||200–201||2012, 2014, 2015|
|Cyanides and nitriles||210–211||2012, 2014, 2015|
|Isocyanates||220–221||2012, 2014, 2015|
|Aliphatic and alicyclic amines||230–233||2012, 2014, 2015|
|Aromatic nitro and amino compounds||250–252||2012, 2014, 2015|
|Aliphatic and miscellaneous nitrogen compounds||260–261||2012|
|Polymers||270–271||2012, 2014, 2015|
|Organophosphate pesticides/Carbamate pesticides||290–292||2012, 2014, 2015|
|Organic sulfur compounds||310–311||2012, 2014, 2015|
|Indoor air pollutants||320.01, 320.33||2012, 2014, 2015|
|Cleaning materials||322||2012, 2014, 2015|
|Miscellaneous chemicals and materials||320.02–320.32, 320.34–321.99, 323–329.3||2012, 2014|
|Miscellaneous chemicals and materials||320.02–320.32, 320.34–321.35, 323.00–327.03||2015|
|Pyrolysis products||330–331||2012, 2014, 2015|
|Physical factors||350–354||2012, 2014, 2015|
|Ergonomics||360–362||2012, 2014, 2015|
|Plant materials||370–373||2012, 2014|
|Animal materials||380–382||2012, 2014|
|Microorganisms, not including mold||390.00, 390.02–390.16, 391.09–391.11, 390.13||2012, 2014|
|Microorganisms, not including mold||390.00–390.16, 391.10–391.11, 390.13||2015|
|Mold||390.01, 390.12, 391.01–391.08||2012, 2014|
|Hazard not on file||000.00||2012, 2014, 2015|
|n.o.s. - not otherwise specified|
A single case of WRA may be associated with up to three putative agents and as a result may be counted in more than one category. The AOEC designation of agents as occupational asthmagens on the exposure code list is made according to an AOEC protocol (see Revised Protocol: Criteria for Designating Substances as Occupational Asthmagens on the AOEC List of Exposure Codes at http://www.aoec.org/content/Asthmagen_Protocol_10-25-08.pdf.
For each agent, an indication of whether the agent has a high or low molecular weight is presented. Based on the Environmental Protection Agency standards, high molecular weight is defined as a molecular weight greater than or equal to 10,000 Daltons, and low molecular weight is defined as a molecular weight less than 10,000 Daltons. High and low molecular weights were determined using the Toxicology Data Network for the National Library of Medicine (http://toxnet.nlm.nih.gov/); NIOSH Pocket Guide to Chemical Hazards (http://www.cdc.gov/niosh/npg/default.html); PubChem Substance (http://pubchem.ncbi.nlm.nih.gov/); and Asthma in the Workplace2.
Industry/Occupation Codes and Titles
The primary industries and occupations associated with state-based surveillance silicosis and work-related asthma case data prior to June 2008 updates are grouped by the 1987 Standard Industrial Classification (SIC) system for industries and the 1990 Census Occupation Codes (COC) for occupations. Current presentation of primary industries and occupations are grouped using the 2002 North American Industry Classification System (NAICS), the 2000 COC, and the 2000 Standard Occupational Classification (SOC). Industries and occupations associated with five or more silicosis cases are listed. Industries and occupations associated with 10 or more work-related asthma cases using 1993–2008 data and five or more work-related asthma cases using 2009–2011 data are listed. Industries and occupations associated with less than five silicosis cases or with less than 10 work-related asthma cases using 1993–2008 data and less than five work-related asthma cases using 2009–2011 data are aggregated in an "All other" category.
1 Hunting KL, McDonald SM. Development of a hierarchical coding system for clinic-based surveillance of occupational disease and industry. Appl Occup Environ Hyg 1995;10(4):317–322. (Return to text)
2 Bernstein, IL, Chan-Yeung, M, Malo, JL, Berstein,
DI. Asthma in the workplace, 3rd, Taylor and Francis, New York 2006.
(Return to text)
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