I received an email from the TSA about my question about bringing toner cartridges on domestic flights. It stated:
The Transportation Security Administration (TSA) no longer restricts passengers from carrying toner and ink cartridges on domestic and international passenger flights to the United States. This provision also applies to certain inbound international air cargo shipments. Toner and ink cartridges are now permitted in carry-on bags and checked luggage.
Charles C. Goodin