SCOPE

Cutting oils, emulsions (also called lubricants or coolants) and drawing pastes or compounds are used in metal cutting and drawing processes to cool, reduce friction, produce a smooth finish and to protect the finished work from rust and corrosion.  Cutting oils may be of animal, vegetable, or mineral origin and frequently are a mixture.  Soluble cutting oils usually contain mineral oil, soap, and a preservative component such as cresol, phenol, glycol, alcohol or nitrobenzene and are used primarily as coolants.  Insoluble cutting oils are used primarily as lubricants and usually consist of fatty and petroleum oils.  They may be sulfurized with free or combined sulfur, or they may be chlorinated or sulfo-chlorinated.  Some contain an inhibitor, generally one of the amines.
Cutting oils and compounds are frequently blamed for almost every type of skin disorder occurring among metal workers. However, cutting oils and compounds become a source of skin problems only after contamination through poor personal-hygiene habits, or through contact with machine parts or other items in the working environment. Infection is usually a secondary effect.

1. Effects on Skin and Lungs
1. The primary effects cutting oils may have on the skin are plugging of the pores; defatting of the skin; imbedding of metal slivers from wiping cloths, resulting in secondary infection; irritation and sensitization by inhibitors; and possible pre-malignant skin lesions.
   
   When there is excessive or prolonged exposure to contaminated cutting oils, good hygiene is not being practiced.  Several types of dermatitis can develop:  oil acne; oil dermatitis; cracking of the skin, with resultant infections; skin pigmentation and chlor-acne.
   
   A very important factor in the development of machine operators’ skin problems is the mechanical injury caused by metal chips and particles.  Hot chips flying off the machine frequently strike the hands and arms of the operator, cutting the skin and leaving openings for bacteria.  In light cutting, fine particles of metal in the oil can be transmitted to the operator’s hands and arms, particularly when the oil issued over and over without being filtered.  For example, when an operator wipes oil off his hands with a cloth used to wipe the machine, metal particles may scratch the skin and make many small openings, which permit bacteria infection.  It is important to realize that the bacteria present in the cutting oil does not cause dermatitis.  Defatting of the skin so that it cracks open, or scratches from metal particles allows bacteria  to penetrate, causing infection.
   
2. Breathing oil mist has been cited frequently as an agent related to the development of pneumonia.  Although the opinion that this condition could result from exposure to oil mist has been expressed, such a cause-and-effect relationship has not been proven.  However, exposure of personnel to oil mist should be controlled
   
2. Hygienic Practices
   
   Employees should be thoroughly trained and made aware of the implications of poor personal-hygiene habits when working with cutting oils, emulsions and compounds.
   
1. Personal Cleanliness - Personal cleanliness is very important as a means of preventing skin troubles.  Skin problems can be avoided by frequent cleansing of the hands and arms with soap and hot water.  Soaps that are strongly alkaline or contain harsh, abrasive grit, powerful bleaching agents, and solvents such as kerosene and gasoline must not be used for washing purposes.  If frequent washing causes the skin to become dry and cracked, a hand cream containing lanolin should be used after washing.
   
2. Protective Equipment - Many operations may require the use of liquid-proof aprons to prevent the operator’s clothing from becoming contaminated.  (The apron strings must be easily broken, in case the apron gets caught in moving machine parts.)
   
   When sheet stock is handled, hand pads should be worn for protection against cuts and scratches.
   
   Certain types of special hand creams can be used before operators begin work.  However, the cream must be re-applied frequently, since the cream film is easily broken.
    
   Particular care must be exercised to prevent clothing from becoming soaked with the cutting mixture.
   
3. Wiping Material - The use of rags or pieces of waste for wiping hands and arms should not be permitted.  The wiping cloths normally keep around the machines are frequently loaded with chips and dirt and, in many cases, contribute to the development of dermatitis.  Disposable towels should be provided to control this problem.
   
4. Training - Operators should be educated and trained to be aware of the necessity for good hygienic practice when working with these materials.  Plants must insist on the observance of the rules regarding personal cleanliness.
   
3. Methods of Control
   
   Other methods of control, besides good hygienic practices, are careful selection of the fluids, filtration of fluids that have been reclaimed from cuttings and shavings to remove non-ferrous metallic and other particles, disaffection of fluids by heat or addition of a germicide, and providing splash guards and covers to prevent operator exposure.