McDonald nuggets contain the carcinogenic substance thiamine mono nitrate which is used in construction to hold railroads together.

Thiamine mononitrate is a synthetic vitamin B1 commonly added to enriched flour and other food products to prevent nutritional deficiencies. Multiple sources clarify that it is safe for human consumption and approved by food safety agencies. The claim that it is carcinogenic lacks scientific support and is contradicted by regulatory assessments.

Furthermore, the assertion that thiamine mononitrate is used in construction to hold rods or railroads together is unfounded and appears to be a misunderstanding or misinformation. None of the credible sources or food safety authorities report any industrial use of thiamine mononitrate in construction or railroad maintenance. The confusion may stem from mixing up chemical names or misinterpreting ingredient functions.

Other ingredients sometimes discussed in relation to McDonald's nuggets, such as dimethylpolysiloxane (an anti-foaming agent), have no connection to thiamine mononitrate or construction materials. Overall, the evidence strongly refutes the claim.