Phoenix, Ariz.(Bloomberg) -- Petsmart Inc. says it has found mold, including a potentially toxic fungus, at the Phoenix headquarters of the pet-supplies retailer.

The company is offering health screenings to about 700 people who work in the building after an outside consultant identified 10 types of mold inside some walls and on some ceiling tiles. The building was checked after an employee complained that several people had become ill at work, according to a Petsmart spokesperson.

The toxic fungus, called stachybotrys, can cause sore throats, diarrhea, headaches, fatigue or bleeding in the lungs. The consultant, Dominion Environmental, found only a small quantity of the fungus, the spokesperson added.

According to Petsmart, the mold grew in a part of the building that has had problems with leaks since the company occupied it in 1997. Petsmart said it plans to permanently seal the leaks and clean up the building.