Dallas business receives white powder letter

Dallas Fire-Rescue was recently called to investigate a white powder incident at a local office building.

Two employees at the firm Allied Marketing came into close contact with the powder. DFR's Jason Evans said that the employees showed no signs that they were exposed to anything toxic, according to NBCDFW.com.

"They all were quarantined and the air conditioning system was shut down," Evans said, DallasNews.com reports.

A hazardous materials team from Plano, Texas, also responded to the incident. Evans said the Dallas unit would have been called to the scene, but they were investigating a gas leak near an elementary school. The hazmat team the powder, which came back negative for hazardous substances, according to DallasNews.com.

A building operator said all was well at the building and that someone had placed cornstarch into the envelope.

The case will be turned over to the U.S. Federal Bureau of Investigation's Dallas field office.

The number of white powder letters has proliferated since five people were killed and more than a dozen were wounded in 2001 when U.S. government scientist Bruce Ivins allegedly sent powdered anthrax through the U.S. Postal Service. Anyone receiving a letter filled with white powder is advised to report the incident immediately, according to NBCDFW.com.