Burning brake cleaner might create Phosgene gas, there are warnings about using brake cleaner on metal you are going to weld.
Arc Welding 101: Cleaning material with brake cleaner before welding
"Many warnings are found on the chemicals that we use every day. Often I simply assume that if it’s sold over the counter surely it must be safe, but that’s just not the case this time. The Safety Data Sheet (SDS) for a can of brake cleaner reads:
“Do not use this product near open flames, welding operations, or excessive heat. Vapors may decompose to harmful or fatal corrosive gases such as hydrogen chloride and possibly phosgene.”
This can be debilitating or even deadly to the welder or those around him or her. According to the Centers for Disease Control and Prevention (CDC), phosgene is an industrial chemical used to make plastics and pesticides. It does not occur naturally and was used extensively in World War I as a choking agent. It is poisonous at room temperature and can cause coughing, burning in the throat and eyes, blurred vision, shortness of breath, nausea, vomiting, and pulmonary edema. Some of the more serious effects can show up 48 hours after exposure, and those include difficulty breathing, low blood pressure, and heart failure. Chronic bronchitis and emphysema are reported permanent side effects of phosgene exposure. In other words, if it doesn’t kill you, it’s going to alter your health significantly."