Welder’s Safety and Health Guide
INTRODUCTION
Welding often involves a variety of physical and chemical hazards. These hazards are varied and dependant on the type of welding process, and the quantity and type of materials used. These hazards include specific base and filler metals, fluxes, shielding gases and primers.
SAFETY GUIDELINES
Protect workers from welding fumes and gases. Exhaust ventilation may be necessary, especially when welding with particularly hazardous materials, large volumes of materials, or when welding for long periods of time. Proper ventilation is essential in enclosed or confined spaces. Welding tables equipped with slot exhausts, portable welding exhaust ventilation systems including moveable elephant trunk exhaust, and small diameter welding gun mounted fume extractors are commercially available. Air-purifying respirators can filter out metal fumes, they do not protect workers from all of the hazardous gases produced or oxygen deficiency.
Proper cleaning and removal of primers, paints, cleaners and surface coatings from welding surfaces will reduce exposures.
Consider orientation of materials and body position of the welder when laying out the job and conducting the work, allowing the welder to avoid the natural heat rise of the fumes when possible. Exposures can be significantly reduced if welders are not positioned directly over fumes.
Only operate welding equipment you have been trained to use. Know what the substance is that is being welded and any coating on it.
Make sure a fire extinguisher is near for immediate use. Check area before welding to be sure no flammable material or degreasing solvents are near the welding area.
Wear protective clothing to cover all exposed areas of the body (closely woven clothing, long socks, gloves), leak proof welder’s helmet. If goggles are worn, be sure the tint is corrected to protect from ultraviolet and infrared radiation.
If others are working in the area, be sure they are warned of and protected against arc, fumes, sparks, and other welding hazards.
Use spark catchers when working at elevated levels.
Always make sure there is good local exhaust ventilation. Always avoid inhaling fumes of any kind. A NIOSH approved respirator and local exhaust ventilation should be used in all confined areas.
Deposit all scraps and electrode butts in proper waste container to avoid fire and toxic fumes.
Check welding area when job is completed to be sure there are no smoldering materials, hot slag, or live sparks.
Closed containers that have held flammables or combustibles must be properly cleaned or purged before work is started.
Use a fire watchman when welding or cutting on walls, bulkheads, and through doors or other similar situations where you cannot see dangers ahead. First be certain there are no flammable solids, liquids, gases, or vapors behind the bulkhead on which you weld.
Check area for degreasing equipment. No welding should be done within 200 feet of degreasing solvents because deadly phosgene gas is produced by welding near degreasing solvents.
ELECTRIC ARC
Be sure electrode is clear of the conductor before starting work.
Be sure all connections or leads are in place; leads should be installed.
Keep yourself insulated from ground or metal when changing electrodes.
Shut off machine when leaving work; disconnect at the power source.
Never look at a flash even for an instant. Be sure to turn your head completely away from the arc and be careful of reflections. Your eyes can be severely damaged by the infrared rays.
ACETYLENE
Oxygen under pressure reacts violently.
If there is a leak in an oxygen or gas cylinder take it outside and slowly release gas.
Close the cylinder valve as soon as work is finished, or when taking a break for any period of time.
When cylinders are emptied, close the valve, replace the protective cap and mark the cylinder “MT.”
The valve on the acetylene cylinder should never be opened more than one and one-half turns.
Make sure gas systems have check valves to prevent back flow into the fittings and that couplings are secure.
HIGH VOLTAGE
ELECTRODES
Source: Live electrode
Effect: Burns, shocks, electrocution
Control: Cover electrodes, keep splices in safe condition; no welding in wet conditions
FUMES
Control: Local exhaust ventilation; wear an approved NIOSH respirator if in confined area. See a physician if overexposure to welding fumes is suspected
Antimony
Source: Antimony-lead solder
Effect: Irritates skin and eyes; headache and vomiting
Brass
Source: Welding; lead and copper alloy
Effect: Dermatitis; metal fume fever; see also copper and lead effects
Cadmium
Source: Paint, some silver solders, filler materials for welding
Effect: Irritates skin and mucous membranes; gastroenteritis (stomach pain), lung irritation, chest pain, bronchitis, fluid in lungs, chills with fever
Chromium
Source: Adhesives, cement, paint, metal coating, stainless steels
Effect: Bronchitis, skin ulcers, nose, and nasal passage irritant
Copper
Source: Cutting, soldering of copper pipe
Effect: Irritates nose and throat; metal fume fever
Cobalt
Source: Welding fumes and grinding dusts
Effect: Irritates skin; can damage lungs, heart, liver, kidney; metal fume fever
Iron
Source: Welding on iron or steel, scraping iron or steel
Effect: Metal fume fever
Lead
Source: Pipe joints, paints, demolition, remodeling
Effect: Abdominal pain, headache, muscular aches, weakness, central nervous system and kidney damage, anemia, effects on bone marrow; metal fume fever, impotency
Magnesium
Source: Welding fumes and grinding dust
Effect: Metal fume fever
Manganese
Source: Welding electrodes
Effect: Increased levels of manganese in blood and urine; chronic manganese poisoning; headache, apathy, sexual impotence, speech disturbances, slowed reflexes, effects on central nervous system
Nickel
Source: Welding fumes and grinding dust
Effect: Human carcinogen, nickel allergy dermatitis
Tin
Source: Welding fumes and grinding dust
Effect: Metal fume fever
Zinc
Source: Soldering or welding zinc coated or galvanized metal; paint pigment
Effect: Irritation of respiratory tract, dryness of throat, dry coughs, malaise, headache, nausea, severe chills with fever, pains in limbs, shaking in limbs, sweating, metal fume fever
VAPORS
Source: Degreaser solvents; ultraviolet rays in welding can decompose degreasing solvents forming highly toxic gases
Effect: Phosgene is a highly toxic gas which can cause death. Initial effects are irritation to skin, eyes, nose, throat, and chest; dizziness and chills. Delayed effects: 2 to 24 hours after exposure, outpouring of fluid into air sacs of lungs. Can be fatal
Control: Good ventilation; protective clothing; do not weld near degreasing operations as toxic gases can be formed when degreasing solvents are exposed to strong ultraviolet light from welding
GASES
NOTE: When welding in any confined area a respirator should always be used.
Acetylene
Source: Gas used in oxyacetylene welding
Effect: Rapid breathing, loss of coordination; high concentration can cause suffocation
Control: Good local exhaust ventilation
Arsine
Source: Possible contamination of commercial acetylene
Effect: Anemia (breakdown of red blood cells), jaundice, pulmonary edema, irritates eyes, nose, skin, lungs
Control: Good local exhaust ventilation
Carbon Dioxide
Source: Welding by product
Effect: Headache, dizziness, nausea, vomiting; in high concentrations symptoms of suffocation, eventual unconsciousness and eventual suffocation
Control: Good local exhaust ventilation
Carbonic Acid
Source: In a damp atmosphere carbon dioxide combines with water vapor
Effect: Irritates eyes, skin and mucous membranes Control: Good general ventilation and dry work conditions
Nitrogen Dioxide
Source: Welding by product
Effect: Irritates nose, throat, lungs; causes headache, chest pain, drowsiness, hemorrhage, fluid in lungs, lung damage
Control: Good general ventilation (if air smells sweet like electrical storm, stop work immediately and get fresh air)
Ozone
Source: Welding by product
Effect: Irritates nose, throat and eyes; coughing, chest pain, headache, shortness of breath, pulmonary edema
Control: Good general ventilation of welding area (if air smells sweet like electrical storm, stop work immediately and get fresh air)
Phosgene
Source: Welding by product; produced when ultraviolet rays given off by welding decompose degreasing chemicals
Effects: Highly toxic, can cause death. Initial effects are irritation to skin, eyes, nose, throat and chest; dizziness chills, thirst; delayed effects: 2 to 24 hours after exposure the outpouring of fluid into air sacs of lungs can be fatal
Control: No welding should be done within 200 feet of degreasing operations; if gas is smelled, evacuate area immediately
Phosphine
Source: Possible contaminant of commercial acetylene
Effects: Fatigue, tremors, coma, convulsions, pulmonary edema; long term exposure can cause anemia and stomach problems
Control: Good local exhaust ventilation
RADIATION, NON-IONIZING
Ultraviolet
Source: Arc or its reflection
Effect: Irritates and damages eye tissue; can cause painful sunburn and possibly skin cancer
Control: Proper eye protection; clothing covering all parts of the body; separate welders from all other workers
Infrared
Source: Heat waves given off by all bodies that radiate heat
Effect: Can cause damage to parts of the eye; workers may develop a condition called “heat cataract”
Control: Regular clothing; goggles to protect eyes
METALLIC SPARKS/MOLTEN METAL
Sparks
Source: Heated metal, hot metal Effect: Burns, fires
Control: Eye protection; protective clothing including long pants, sleeves, and socks; gloves