SilicaSilicaSpecial Emphasis ProgramSpecial Emphasis Program

OSHA’s Industrial Hygiene initiative Collaboration of OSHA Compliance

and Consultation Programs

Why Target Crystalline Silica Why Target Crystalline Silica Exposure?Exposure?

Widespread occurrence and use Number of related deaths Number of exposed workers Health effects

Occurrence and UseOccurrence and Use

SiO2 - basic component of sand, quartz & granite

Quartz - 2nd most common mineral in the earth’s crust

Airborne silica is produced by:

Industries Industries

electronics foundries ceramics, clay,

pottery, stone, and glass

construction agriculture maritime

railroad slate and flint

quarrying and crushing

use and manufacture of abrasives

mining

Occurrence and UseOccurrence and Use

Airborne silica is produced by:– sandblasting– rock drilling– foundry work– stone cutting– drilling– quarrying

– tunneling jack hammering

– concrete manufacturing– demolition– asphalt pavement

manufacturing

General Industry TargetingGeneral Industry Targeting

Focused to particular establishments where overexposures to crystalline silica are most likely or known.

Records review– Silicosis diagnosis may include:

pneumoconiosis, fibrosis, respiratory disease, non- malignant respiratory disease, congenital heart failure

10 mg/m3

% Quartz +2

Permissible Exposure LimitPermissible Exposure Limit(PEL)(PEL)

= ? mg/m3

PEL for respirable dust containing a % silica.

Respiratory ProtectionRespiratory Protection

up to 0.25mg/m3

up to 0.50 mg/m3

up to 1.25 mg/m3

up to 2.5 mg/m3

up to 50 mg/m3

dust respirator dust/mist,SAR, SCBA,

no single use or quarter mask

PAPR, SAR

APR w/HEPA, tight- PAPR w/HEPA, full face SAR or SCBA

SAR pressure demand

Silicosis Prevention ProgramSilicosis Prevention Program

Medical surveillance program – baseline examination

medical and occupational history prior to exposure

– every 5 years if < 20 years of exposure– every 2 years if > 20 years of exposure– baseline chest x-ray– pulmonary function tests (PFT)– x-ray upon termination of employment

Source: OSHA SEP

Silicosis Prevention ProgramSilicosis Prevention Program

Personal air monitoring program Training and information on crystalline

silica Availability of air and medical

surveillance data to workers Respiratory protection program

Source: OSHA SEP

Silicosis Prevention ProgramSilicosis Prevention Program

Hygiene facilities and clothing change areas

Recordkeeping Personal exposures below the PEL OR

facility has an abatement program that provides interim worker protection

Housekeeping program Regulated areas

Source: OSHA SEP

Prevention of Silica Related Prevention of Silica Related DiseasesDiseases

250 Worker deaths per year Silicosis Silicosis/TB Lung Cancer

Health EffectsHealth Effects

Acute - intense crystalline silica exposure– acute silicosis (silico-proteinosis)– inflammation in the gas exchange area

of the lung– fibrosis

Health EffectsHealth Effects

Accelerated - more intense exposure over 5 to 15 years– silicosis– smaller fibrotic nodules– massive fibrosis in the mid-zones of the lungs– shortness of breath – fever– bluish skin at ear lobes or lips

Health EffectsHealth Effects

Chronic - 20 to 45 years prolonged exposure to crystalline silica– silicosis– nodular lesions in upper lobes– shortness of breath with exertion– cough and expectoration– fatigue– loss of appetite– chest pain (airway obstruction)

* x-ray (after 15-20 years) *

Common HazardCommon Hazard

Abrasive Blasting

Paint Removal

Renovation & Demolition

Road Repair

Exposure Controls Exposure Controls SubstitutionSubstitution

Coal slag (black beauty) Steel grit Aluminum oxide Wild stuff (frozen co2,

walnut shells, baking soda)

Exposure ControlsExposure ControlsWet MethodsWet Methods

Water suppression of dust Very effective method May be less efficient Requires supply of water and clean

up

Exposure ControlsExposure Controls

Power tools with HEPA exhaust