Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-840 - Respirable crystalline silica › Section 296-840-170 - Appendix B-Medical surveillance guidelines-Nonmandatory

Current through Register Vol. 24-14, July 15, 2024
Introduction.
The purpose of this Appendix is to provide medical
				information and recommendations to aid physicians and other licensed
				health care professionals (PLHCPs) regarding compliance with the
				medical surveillance provisions of the respirable crystalline silica
				standard (chapter 296-840 WAC, Respirable crystalline silica).
				Appendix B is for informational and guidance purposes only and none
				of the statements in Appendix B should be construed as imposing a
				mandatory requirement on employers that is not otherwise imposed by
				the standard.
Medical screening and surveillance allow for early
				identification of exposure-related health effects in individual
				employee and groups of employees, so that actions can be taken to
				both avoid further exposure and prevent or address adverse health
				outcomes. Silica-related diseases can be fatal, encompass a variety
				of target organs, and may have public health consequences when
				considering the increased risk of a latent tuberculosis (TB)
				infection becoming active. Thus, medical surveillance of
				silica-exposed employees requires that PLHCPs have a thorough
				knowledge of silica-related health effects.
This Appendix is divided into eight sections. Section
				1 reviews silica-related diseases, medical responses, and public
				health responses. Section 2 outlines the components of the medical
				surveillance program for employees exposed to silica. Section 3
				describes the roles and responsibilities of the PLHCP implementing
				the program and of other medical specialists and public health
				professionals. Section 4 provides a discussion of considerations,
				including confidentiality. Section 5 provides a list of additional
				resources and Section 6 lists references.
Section 7 provides sample forms for the written
				medical report for the employee, the written medical opinion for the
				employer and the written authorization. Section 8 provides
				information regarding Washington state reporting requirements for
				tuberculosis.
1.
Recognition of Silica-related Diseases.
1.1. Overview. The term "silica"
			 refers specifically to the compound silicon dioxide
			 (SiO2). Silica is a major component of sand,
			 rock, and mineral ores. Exposure to fine (respirable size) particles
			 of crystalline forms of silica is associated with adverse health
			 effects, such as silicosis, lung cancer, chronic obstructive
			 pulmonary disease (COPD), and activation of latent TB infections.
			 Exposure to respirable crystalline silica can occur in industry
			 settings such as foundries, abrasive blasting operations, paint
			 manufacturing, glass and concrete product manufacturing, brick
			 making, china and pottery manufacturing, manufacturing of plumbing
			 fixtures, and many construction activities including highway repair,
			 masonry, concrete work, rock drilling, and tuck-pointing. New uses of
			 silica continue to emerge. These include countertop manufacturing,
			 finishing, and installation (Kramer et al. 2012; OSHA 2015) and
			 hydraulic fracturing in the oil and gas industry (OSHA 2012).
Silicosis is an irreversible, often disabling, and
				sometimes fatal fibrotic lung disease. Progression of silicosis can
				occur despite removal from further exposure. Diagnosis of silicosis
				requires a history of exposure to silica and radiologic findings
				characteristic of silica exposure. Three different presentations of
				silicosis (chronic, accelerated, and acute) have been defined.
				Accelerated and acute silicosis are much less common than chronic
				silicosis. However, it is critical to recognize all cases of
				accelerated and acute silicosis because these are life-threatening
				illnesses and because they are caused by substantial overexposures to
				respirable crystalline silica. Although any case of silicosis
				indicates a breakdown in prevention, a case of acute or accelerated
				silicosis implies current high exposure and a very marked breakdown
				in prevention.
In addition to silicosis, employees exposed to
				respirable crystalline silica, especially those with accelerated or
				acute silicosis, are at increased risks of contracting active TB and
				other infections (ATS 1997; Rees and Murray 2007). Exposure to
				respirable crystalline silica also increases an employee's risk of
				developing lung cancer, and the higher the cumulative exposure, the
				higher the risk (Steenland et al. 2001; Steenland and Ward 2014).
				Symptoms for these diseases and other respirable crystalline
				silica-related diseases are discussed below.
1.2. Chronic Silicosis. Chronic
			 silicosis is the most common presentation of silicosis and usually
			 occurs after at least 10 years of exposure to respirable crystalline
			 silica. The clinical presentation of chronic silicosis is:
1.2.1. Symptoms - shortness of
			 breath and cough, although employees may not notice any symptoms
			 early in the disease. Constitutional symptoms, such as fever, loss of
			 appetite and fatigue, may indicate other diseases associated with
			 silica exposure, such as TB infection or lung cancer. Employees with
			 these symptoms should immediately receive further evaluation and
			 treatment.
1.2.2.
			 Physical Examination - may be normal or disclose dry rales or rhonchi
			 on lung auscultation.
1.2.3. Spirometry - may be normal
			 or may show only a mild restrictive or obstructive pattern.
1.2.4. Chest X-ray - classic
			 findings are small, rounded opacities in the upper lung fields
			 bilaterally. However, small irregular opacities and opacities in
			 other lung areas can also occur. Rarely, "eggshell calcifications" in
			 the hilar and mediastinal lymph nodes are seen.
1.2.5. Clinical Course - chronic
			 silicosis in most cases is a slowly progressive disease. Under the
			 respirable crystalline silica standard, the PLHCP is to recommend
			 that employees with a 1/0 category X-ray be referred to an American
			 Board Certified Specialist in Pulmonary Disease or Occupational
			 Medicine. The PLHCP and/or Specialist should counsel employees
			 regarding work practices and personal habits that could affect
			 employees' respiratory health.
1.3. Accelerated Silicosis.
			 Accelerated silicosis generally occurs within 5-10 years of exposure
			 and results from high levels of exposure to respirable crystalline
			 silica. The clinical presentation of accelerated silicosis is:
1.3.1. Symptoms - shortness of
			 breath, cough, and sometimes sputum production. Employees with
			 exposure to respirable crystalline silica, and especially those with
			 accelerated silicosis, are at high risk for activation of TB
			 infections, atypical mycobacterial infections, and fungal
			 superinfections. Constitutional symptoms, such as fever, weight loss,
			 hemoptysis (coughing up blood), and fatigue may herald one of these
			 infections or the onset of lung cancer.
1.3.2. Physical Examination -
			 rales, rhonchi, or other abnormal lung findings in relation to
			 illnesses present. Clubbing of the digits, signs of heart failure,
			 and cor pulmonale may be present in severe lung disease.
1.3.3. Spirometry - restrictive or
			 mixed restrictive/obstructive pattern.
1.3.4. Chest X-ray - small rounded
			 and/or irregular opacities bilaterally. Large opacities and lung
			 abscesses may indicate infections, lung cancer, or progression to
			 complicated silicosis, also termed progressive massive
			 fibrosis.
1.3.5. Clinical
			 Course - accelerated silicosis has a rapid, severe course. Under the
			 respirable crystalline silica standard, the PLHCP can recommend
			 referral to a Board Certified Specialist in either Pulmonary Disease
			 or Occupational Medicine, as deemed appropriate, and referral to a
			 Specialist is recommended whenever the diagnosis of accelerated
			 silicosis is being considered.
1.4. Acute Silicosis. Acute
			 silicosis is a rare disease caused by inhalation of extremely high
			 levels of respirable crystalline silica particles. The pathology is
			 similar to alveolar proteinosis with lipoproteinaceous material
			 accumulating in the alveoli. Acute silicosis develops rapidly, often,
			 within a few months to less than 2 years of exposure, and is almost
			 always fatal. The clinical presentation of acute silicosis is as
			 follows:
1.4.1. Symptoms - sudden,
			 progressive, and severe shortness of breath. Constitutional symptoms
			 are frequently present and include fever, weight loss, fatigue,
			 productive cough, hemoptysis (coughing up blood), and pleuritic chest
			 pain.
1.4.2. Physical
			 Examination - dyspnea at rest, cyanosis, decreased breath sounds,
			 inspiratory rales, clubbing of the digits, and fever.
1.4.3. Spirometry - restrictive or
			 mixed restrictive/obstructive pattern.
1.4.4. Chest X-ray - diffuse
			 haziness of the lungs bilaterally early in the disease. As the
			 disease progresses, the "ground glass" appearance of interstitial
			 fibrosis will appear.
1.4.5. Clinical Course - employees
			 with acute silicosis are at especially high risk of TB activation,
			 nontuberculous mycobacterial infections, and fungal superinfections.
			 Acute silicosis is immediately life-threatening. The employee should
			 be urgently referred to a Board Certified Specialist in Pulmonary
			 Disease or Occupational Medicine for evaluation and treatment.
			 Although any case of silicosis indicates a breakdown in prevention, a
			 case of acute or accelerated silicosis implies a profoundly high
			 level of silica exposure and may mean that other employees are
			 currently exposed to dangerous levels of silica.
1.5. COPD. COPD, including chronic
			 bronchitis and emphysema, has been documented in silica-exposed
			 employees, including those who do not develop silicosis. Periodic
			 spirometry tests are performed to evaluate each employee for
			 progressive changes consistent with the development of COPD. In
			 addition to evaluating spirometry results of individual employees
			 over time, PLHCPs may want to be aware of general trends in
			 spirometry results for groups of employees from the same workplace to
			 identify possible problems that might exist at that workplace. (See
			 Section 2 of this Appendix on Medical Surveillance for further
			 discussion.) Heart disease may develop secondary to lung diseases
			 such as COPD. A recent study by Liu et al. 2014 noted a significant
			 exposure-response trend between cumulative silica exposure and heart
			 disease deaths, primarily due to pulmonary heart disease, such as cor
			 pulmonale.
1.6. Renal and
			 Immune System. Silica exposure has been associated with several types
			 of kidney disease, including glomerulonephritis, nephrotic syndrome,
			 and end stage renal disease requiring dialysis. Silica exposure has
			 also been associated with other autoimmune conditions, including
			 progressive systemic sclerosis, systemic lupus erythematosus, and
			 rheumatoid arthritis. Studies note an association between employees
			 with silicosis and serologic markers for autoimmune diseases,
			 including antinuclear antibodies, rheumatoid factor, and immune
			 complexes (Jalloul and Banks 2007; Shtraichman et al.
			 2015).
1.7. TB and Other
			 Infections. Silica-exposed employees with latent TB are 3 to 30 times
			 as likely to develop active pulmonary TB infection (ATS 1997; Rees
			 and Murray 2007). Although respirable crystalline silica exposure
			 does not cause TB infection, individuals with latent TB infection are
			 at increased risk for activation of disease if they have higher
			 levels of respirable crystalline silica exposure, greater profusion
			 of radiographic abnormalities, or a diagnosis of silicosis.
			 Demographic characteristics, such as immigration from some countries,
			 are associated with increased rates of latent TB infection. PLHCPs
			 can review the latest Centers for Disease Control and Prevention
			 (CDC) information on TB incidence rates and high risk populations
			 online. (See Section 5 of this Appendix.) Additionally,
			 silica-exposed employees are at increased risk for contracting
			 nontuberculous mycobacterial infections, including Mycobacterium
			 avium-intracellulare and Mycobacterium kansaii.
1.8. Lung Cancer. The National
			 Toxicology Program has listed respirable crystalline silica as a
			 known human carcinogen since 2000 (NTP 2014). The International
			 Agency for Research on Cancer (2012) has also classified silica as
			 Group 1 (carcinogenic to humans). Several studies have indicated that
			 the risk of lung cancer from exposure to respirable crystalline
			 silica and smoking is greater than additive (Brown 2009; Liu et al.
			 2013). Employees should be counseled on smoking cessation.