If metalworking fluids are stored for a long time, nitrosamines will be produced. Nitrosamines are carcinogens. Water-based metalworking fluids will slowly generate nitrosamines during long-term storage. In addition, containers containing metalworking fluids may also Causes the formation of nitrosamines. Manufacturers and marketers need to check with the drum supplier to ensure that the supplier does not use sodium nitrite in the final rust rinse. Nitrite in rust inhibitors can react with secondary amines in metalworking fluids to form nitrosamine carcinogens. Nitrogen oxides in the air also react slowly with metalworking fluids to form nitrosamines. Nitrosamines in metalworking fluids are a threat to the environment and operators, so it is necessary to do a good job of recycling waste liquids.
In use, how to manage the metalworking fluid is very important. Improper use and maintenance can easily lead to contamination of metalworking fluids, breeding of bacteria, especially water-based metalworking fluids, resulting in deterioration of metalworking fluids. Because bacteria can destroy the properties of the emulsifier and cause the metalworking fluid to denature at the same time. In terms of occupational hygiene, the use of metalworking fluids contaminated with bacteria can form bioaerosols, which have an impact on the health of operators. Metalworking fluids may incorporate metal chips, such as nickel, chromium, etc., during processing. In addition, polycyclic aromatic hydrocarbons may be generated during the use of metalworking oils under the action of high temperatures.
Routes of exposure to metalworking fluids Inhalation: Mist, aerosol, and vapor generated during the use of metalworking fluids can be inhaled. Exposure depends on: ○ Processing type. ○Addition method of Metal Working Fluid (such as manual, conveying through hose/pipe, atomization). ○Containment and ventilation of processing equipment. Higher exposures are generally due to: ○ Operators approaching metalworking equipment ○Use high-speed cutting or deep cutting technology ○ Metal processing equipment is poorly sealed ○Ventilation is poor. Skin Contact
Metalworking fluids can cause contact dermatitis through skin contact. When workers replace metal workpieces, if they do not take effective hand protection, they can directly contact the metal working fluid on the surface of the metal workpiece. Ingest Workers smoking, drinking, and eating on the site may cause ingestion exposure to the digestive tract. MWFs occupational exposure limits and detection methods China China's GBZ 2.1-2007 does not formulate occupational exposure limits for MWFs. In GB/T 27946-2011, the PC-TWA of oil mist (total particulate matter) is 5mg/m3 and PC-STEL is 10mg/m3. The detection method is in accordance with GB/T 27946-2011.
America
According to the REL of "What You Need To Know About Occupational Exposure to Metalworking Fluids" published by NIOSH in 1998, the MWFs thoracic particulate matter limit is 0.4mg/m3 and the total particulate matter limit is 0.5mg/m3, applicable to all metalworking liquid. The detection method of metal cutting fluid is in accordance with NIOSH 5524, and the detection method of oil mist can be in accordance with NIOSH 5026. The US OSHA has established a limit of 5mg/m3 for mineral oil (oil mist, total particulate matter), and the detection method is in accordance with OSHA's ID-128. The actual work determines the detection method according to the type of metalworking fluid. If metalworking oil (pure mineral oil) is encountered, oil mist (total particulate matter) can be detected, and semi-synthetic and fully synthetic metalworking fluids can be detected according to NIOSH 5524. Carry out the measurement (currently it cannot be done in China, so it can only be a simple qualitative analysis). As for other chemical additives in metalworking fluids, they can be identified and detected (like ethanolamine, etc., generally not detected) or a simple qualitative analysis. Metalworking Fluid Hazard Control Alternative: Use a low toxicity metalworking fluid if possible. Process Design and Operation ○The metal working fluid is delivered at low pressure. ○Use fog suppressants for metal working fluids. ○ Decrease the metalworking fluid flow rate. ○The metal working fluid raw material barrel and recovery system are covered to avoid microbial contamination. ○ Maintain equipment properly (to avoid contamination from metalworking fluid leakage). ○ After the machining is stopped, the supply of the metal working fluid is stopped. (Only available during workpiece machining). ○ Try not to use compressed air to purge the workpiece (purging will increase MWFs escape). Isolate Make sure the equipment has a complete enclosure or baffle and workers are kept as far away from the equipment as possible. Local Exhaust Set up effective local exhaust and oil mist recovery systems, and use closed exhaust hoods as much as possible. Personal Protection (PPE) for Metalworking Fluids Gloves, protective glasses, protective clothing, respiratory protection. Most of the aerosols produced by metalworking fluids are oily particles, so it is necessary to choose the KP series conforming to GB 2626, or the R\P series conforming to 42 CFR-84, or the FFP series conforming to EU EN 149; 2001 (all series can be protected Oily and non-oily particles), a disposable half mask can be used when the concentration is low, and PAPR or SAR can be selected for a high concentration.
