THQ's promotional partner was video game distributor GameStop. GameStop's name appeared on the balloons, many of which also carried promotional flyers.
"We understand the concerns consumers have regarding the impact balloons can have on the environment," GameStop said on their Facebook page. "However, the balloon drop stunt in San Francisco was created by THQ, the publisher of Homefront, and GameStop had no prior knowledge of it. THQ has since informed us that they released soy-based, biodegradable balloons."
Since I had never heard of soy-based ballloons, I called a few balloon manufacturers and distributors but was unable to find anyone selling soy-based balloons. No one I talked to had even heard of the product.
Continuing the search for soy balloons, I called THQ's vice president of investor relations and corporate communications and left a message. She was kind enough to return my call and confirm that the balloons were not soy, but indeed made of latex.
IMAGE 1: Balloons float on San Francisco Bay after a THQ/GameStop publicity stunt (Credit: Twitter user seedlingproject).