HISTORY OF SILICOSIS Ancient Greece 1870 term first used Hawk’s Nest Dam
Amorphous –Crystalline –NOT Crystalline –Beach Sand Crystalline –Heat and/or pressure converts amorphous –Dangerous to the human body –Found in construction materials (e.g. brick, rock, concrete, masonry block, etc.) TYPES OF SILICA
CRYSTALLINE SILICA 3 Types Where is it found? Naturally Occurring Crystalline Mineral in Earth’s Crust quartz tridymite cristobalite
Silicosis Bronchitis Tuberculosis Association with Lung Cancer –IARC Classification April 1997 –Class 1: Carcinogenic to Humans HEALTH EFFECTS
Chronic –10 or More Years of Exposure –Low Exposure Concentrations Accelerated –5 to 10 Years After Exposure –High Exposure Concentrations Acute –A Few Weeks to 4 or 5 Years After Exposure –Highest Exposure Concentrations SILICOSIS
SYMPTOMS Difficulty in Breathing Cough Infections Causing –Fever –Weight Loss –Night Sweats
CONSTRUCTION INDUSTRY Approximately 4.9 million actively working construction workers 700,000 potentially exposed to silica Approximately deaths each year from silicosis Silicosis is 100 percent preventable
Chipping, Hammering, Drilling of Rock Crushing, Loading, Hauling, and Dumping of Rock Abrasive Blasting With Silica Sand Abrasive Blasting of Concrete CONSTRUCTION JOBS AT RISK
Local Silica Inspection Scheduling Mostly OSHA “drive-by”observations A few telephone or written complaints
Jackhammer (Dry) Example 7.6% silica 1 mg/m3 PEL 0.9 mg/M3 (454 mins) 0.85 mg/M3 8 hour TWA 8 hour severity 85% of PEL VERY CLOSE TO PEL Jackhammering on bridge over I-88, DeKalb, IL Adjacent jackhammer and sweeping may increase exposure
Jackhammer (Wet) Example 10% silica 0.83 mg/m3 PEL 1.8 mg/M3 (370 min) 1.4 mg/M3 8 hr TWA 8 hour severity 165% of PEL EXCEEDED PEL Inside Chicago building, employee at left sprayed with hose 2nd sample 110% of PEL
Concrete Cutting (Dry) Example 12% silica 0.7 mg/M3 PEL 16.3 mg/M3 (39 min) 0.75 mg/M3 8 hr TWA 8 hour severity 105% of PEL EXCEEDED PEL Gas saw dry cuts hole in concrete sewer 2300% of PEL for 39 minute sample time
Concrete Cutting (Wet) Example 9.4% silica 0.9 mg/M3 PEL 0.4 mg/M3 (340 min) 0.3 mg/M3 8 hr TWA 8 hour severity 37% of PEL DID NOT EXCEED PEL Wet saw 2nd sample 45% of PEL
Concrete Cutting Summary Wet Cutting Nine air samples All were wet sawing concrete slabs % of PEL WET SAMPLES ALL BELOW PEL USE WET SAW Dry Cutting Eight air samples Four > PEL Highest was 345% of PEL DO NOT DRY CUT
Lateral Drilling Example 7.5% silica 1.1 mg/M3 PEL 3.1 mg/M3 (420 min) 2.7 mg/M3 8 hr TWA 8 hour severity 257% of PEL EXCEEDED PEL Lateral drilling multiple holes in pavement for reinforcing bars
Lateral Drilling Summary Nine air samples Four samples > PEL 101%, 104%, 251%, 257% of PEL GOOD CHANCE OF EXCEEDING PEL Half mask adequate in these samples Controls: water not used, can it be used?
Vermeer Saw Used to cut large sections of pavement out of highway reduces need to jackhammer /clean up debris
Vermeer Saw Example 5.5% silica 1.3 mg/m3 PEL 9.6 mg/M3 (80 min) 1.6 mg/M3 8 hr TWA 8 hour severity 120% of PEL PEL EXCEEDED Some water is sprayed from side mount tanks
Shoveling Concrete Summary Four samples No overexposures 4%, 8%, 25%, 60% of PEL PEL NOT EXCEEDED Adjacent operations may increase dust exposure (60% seems high for shoveling)
Heavy Construction Silica Dust Summary Operation#Likely ExpLikely RespNoise Jackhammer dry19> PELhalf mask Jackhammer wet5>PELhalf mask Concrete saw dry8> PELhalf mask Concrete saw wet9< PEL-- Lateral drill9> PELhalf mask Vermeer saw3? > PEL ?96 Bobcat concrete2< PEL-- Shovel concrete4< PEL # - number of samples taken Determinations are based on limited numbers of samples and represent available info as of 3/2000.
Sandblasting Example 3.8% silica 1.7 mg/M3 PEL 18 mg/M3 (385 min) 14 mg/M3 8 hr TWA 8 hour severity 812% of PEL GREATLY EXCEEDED PEL Sandblasting rebar in highway Supplied Air Respirator used
Abrasive Blasting Concrete 4% silica 1.7 mg/M3 PEL 2.7 mg/M3 (340 min) 1.9 mg/M3 8 hr TWA 8 hour severity 116% of PEL EXCEEDED PEL Black Beauty used to blast newly cut grooves in roadway
Crossover/Special Operations Silica Dust Summary Operation#Likely ExpLikely RespNoise Sandblaster7>> PELblast resp Sandblast potman1> PELhalf mask91 Abrasive blaster7> PELblast resp Abrasive potman5< PEL-- Sweep5can > PELhalf mask Ceiling seam grind1> PEL half mask Grind floor w/ vent1> PELhalf mask Tunnel (no silica)4< PEL-- # - number of samples taken Determinations are based on limited numbers of samples and represent available info as of 3/2000.
Citation Summary 1.Overexposure/engineering controls 2. Correct respirator/resp. program 3. Silica hazard training 4. Hearing conservation program/protection 5. Silica safety program 6. Lead exposure (tuckpointing, blasting)
RESPIRATORY PROTECTION PROGRAM Medical Evaluation Fit Test Procedures Training Storage and Cleaning Hazard Assessment Written Program
RESPIRATORY PROTECTION PROGRAM Employer Responsibility Determination of Wearer’s Exposure to Hazards Fit Testing Before Use Random Inspection Training Medical Surveillance
RESPIRATORY PROTECTION PROGRAM Employee Responsibility Fit check the respirator Proper use of respirator Guard against respirator damage Report respirator malfunctions
TYPES OF RESPIRATORS Half Mask Air Purifying Respirator APF=10
TYPES OF RESPIRATORS Full Face Air Purifying Respirator APF= 50
TYPES OF RESPIRATORS Full Face Powered Air Purifying Respirator APF=50
TYPES OF RESPIRATORS Abrasive Blasting Type CE Positive Pressure Blast Hood APF= ,000
Memorandum to Regional Offices May 2, 1996 Currently being enforced across the United States OSHA’S SPECIAL EMPHASIS PROGRAM (SEP)
There is No Silica Standard If Contractor is Making Effort, No Inspection If Not, Inspection and Can Fine for PEL Violation or Respiratory Protection
Elements of an Effective, On-going Control Program for Crystalline Silica Personal air monitoring Medical surveillance Training Availability of monitoring/surveillance data to workers Respiratory protection program Hygiene facilities/clothing change areas
Elements of a Control Program (cont’d) Recordkeeping Exposures below PEL or abatement program with interim protection Housekeeping In construction: a Safety & Health program Regulated areas
Conclusions Dry operations: High likelihood of silica dust overexposure Wet operations: Low potential for silica dust overexposure Exposures may be multiplied by factors such as interior workplace and corner location.
Lead Exposure in Roadway Construction Torch cutting on bridge structures that are finished with lead containing paint Scraping or abrasive blasting to remove lead paint on bridges
Chronic Health Hazards Anemia ug/dl Neurological ug/dl Slowed nerve ug/dl conduction in peripheral nerves Blood pressure increases Kidney damage100ug/dl Colic60ug/dl Acute Health Hazards
Reproductive Hazards Acute and chronic –Depressed sperm count in males and spontaneous abortion in women ug/dl –Effects on a fetus ug/dl (Maternal) Low birth weightLow birth weight Premature birthPremature birth Impaired mental developmentImpaired mental development
Compliance Program Prior to the start of each job Compliance plan shall include: – –Description of each activity Equipment used, material involved, controls in place, crew size, employee job – –Specific means to achieve compliance Engineering controls – –Technology considered in meeting the PEL – –Air monitoring which documents the source of lead emissions – –Schedule for implementation Copies of purchase orders for equipment, construction contracts – –Work practice program PPE, hygiene facilities, housekeeping – –Administrative control schedule Job Rotation – –Multi-contractor sites
Compliance Program Frequent and regular inspection of the job site, materials, and equipment by a competent person Shall be revised and updated every 6 months to reflect the current status of the program
Training Annual training for each employee subject to lead exposure at or above the AL on any day Training content –Content of the standard –Nature of operations –Respirators –Medical surveillance program –Engineering controls –Compliance plan –Chelating agents –Access to records
Noise/ Hearing Conservation Program (HCP) Effective HCP under –Monitoring of employee noise exposures. –The institution of engineering, work practice, and administrative controls for excessive noise. –The provision of each overexposed employee with an individually fitted hearing protector with an adequate noise reduction rating. –Employee training and education regarding noise hazards and protection measures.
Occupational Exposure to Asphalt Paving asphalts, roofing asphalts, asphalt-based paints –Performance specifications-not chemical composition-direct the type of asphalt produced. Acute toxic effects of asphalt fume exposures include eye, nose and throat irritation
Occupational Exposure to Asphalt Insufficient evidence for an association between lung cancer & exposure to asphalt fumes during paving. –Low concentrations of PAHs (polycyclic aromatic hydrocarbons) at low temperatures. Temperature of hot-mix asphalt (asphalt cement + mineral aggregate) as applied to the roadway is generally between 235 and 325 F.Temperature of hot-mix asphalt (asphalt cement + mineral aggregate) as applied to the roadway is generally between 235 and 325 F. –Confounding variables Smoking, silica, diesel exhaustSmoking, silica, diesel exhaust
Occupational Exposure to Asphalt Recommended guidelines to reduce exposure: –Prevent dermal exposure –Keep application temperature of heated asphalt as low as possible. –Use engineering and work practice controls and personal protective equipment at all work sites. CDC-NIOSH December 2000 Hazard Review ( NIOSH) to receive a copy.
Heat Stress Too much heat can make you tired, hurt your job performance, and increase your chance of injury. You can get skin rash. You can also get: – –Dehydration- When your body loses water, you can't cool off fast enough. You feel thirsty and weak. – –Cramps- You can get muscle cramps from the heat even after you leave work. – –Heat exhaustion- You feel tired, nauseous, headachy, and giddy (dizzy and silly). Your skin is damp and looks muddy or flushed. You may faint. – –Heat stroke- You may have hot dry skin and a high temperature, or you may feel confused. You may have convulsions or become unconscious. Heat stroke can kill you unless you get emergency medical help.
Heat Stress Drink a lot of cool water all day— before you feel thirsty. Every 15 minutes, you may need a cup of water (5 to 7 ounces). Keep taking rest breaks. Rest in a cool, shady spot. Use fans. Wear light-colored clothing, made of cotton. Do the heaviest work in the coolest time of the day. Work in the shade. For heavy work in hot areas, take turns with other workers, so some can rest.
Heat Stress If you travel to a warm area for a new job, you need time for your body to get used to the heat. Be extra careful the first 2 weeks on the job. If you work in protective clothing, you need more rest breaks. You may also need to check your temperature and heart rate. If you think someone has heat stroke, CALL emergency services (or 911). And move your co- worker to the shade, wipe his/her skin with cool water, and loosen his/her clothes. Use a piece of cardboard or other material to fan your co-worker.