Substance-Specific Issues

Cutting oils and fluids containing nitrites and alkanolamines; prohibition

Substances:

Nitrites; CAS No. 14797-65-0

Prohibition:

By virtue of their inclusion as Item 32 in Part I of Schedule I to the Hazardous Products Act (HPA):

cutting oils and cutting fluids, for use in lubricating and cooling the cutting area in machining operations, that contain more than 50 micrograms per gram of any nitrite, when monoethanolamine, diethanolamine or triethanolamine is also present

are prohibited from sale, importation and advertisement in Canada.

Background:

Nitrosamines, suspected human carcinogens, were found to be present in a number of cutting oils and fluids. Nitrosamines are formed as a result of a reaction between alkanolamines (added as emulsifiers) and nitrites (added as corrosion inhibitors). Therefore, cutting oils or fluids containing more than 50 micrograms per gram of any nitrite, together with monoethanolamine, diethanolamine or triethanolamine were banned.

Industrial operations requiring the grinding, cutting, or boring of metal parts also require the use of metalworking fluids to meet productivity and quality requirements. Metalworking fluids (MWFs) have two primary functions: to cool and to lubricate.

All metal removal processes generate a tremendous amount of heat. This heat must be reduced in order to achieve productivity and part quality. The cooling effect provided by a metalworking fluid gives the cutting tool or grinding wheel a longer life and helps to prevent burning and smoking. At the point where the tool is in contact with the part, lubrication is necessary to reduce friction between the tool and the part, resulting in improved tool life and better finishes on the metal cut.

Metalworking fluids also provide corrosion protection for the newly machined part and machine tool. Water-miscible metalworking fluid formulations (those fluids that are meant to be diluted with water) include components that slow or prevent such corrosion. MWFs also help remove chips or swarf (an accumulation of fine metal and abrasive particles) from the cutting zone.

There are four major classes of metal-working fluids widely available: straight oil, soluble oil, semisynthetic, and synthetic. Many metalworking fluids, except the straight oils, are mixed with water for use. Each has additives such as surfactants, biocides, extreme pressure agents, anti-oxidants, and corrosion inhibitors to improve performance and increase fluid life.

Reference:

U.S. Department of Labour, Metalworking Fluids Standard Advisory Committee, Occupational Safety and Health Administration; "Metalworking Fluids: Safety and Health Best Practices Manual"; 2001; http://www.osha- slc.gov/SLTC/metalworkingfluids/metalworkingfluids_manual.html