Michael Bolton, the US Capitol Police inspector general, told the House of Representatives Administration Committee that such equipment, which release dozens of small, stinging balls, "would have provided a better posture to repel the attacks."
Bolton said better training would have been the remedy to that concern.
Committee Chairwoman Zoe Lofgren said investigators found that riot shields were locked in a bus too far away from police officers to quickly gain access to them during the Jan. 6 attack, forcing officers to face a violent, unruly mob with inadequate protective equipment.
Former President Trump and some of his fellow Republicans have tried to downplay the attack, when hundreds of his supporters stormed the Capitol in an attempt to disrupt Congress' certification of Joe Biden's presidential election victory.
Five people, including Capitol Police officer Brian Sicknick, died in the violence, and many more officers suffered injuries. Lawmakers were forced to huddle in secure rooms while law enforcement battled the rioters.
Bolton's reports to Congress found the Capitol Police Civil Disturbance Unit was operating on Jan. 6 "at a decreased level of readiness" and that the department needed to improve its management of weapons, ammunition and riot shields.
Internal investigations led to recommendations that the Capitol Police immediately improve its intelligence operations and beef up the readiness of the civil disturbances unit