The secondary collision occurred about one kilometre west of the first and involved seven tractor trailers and three vehicles.
Kingston General Hospital says it was told to expect about 10 people, including one person in critical condition, but gave no more details.
OPP said the person who died was the driver of a transport truck that was carrying a hazardous chemical. The emergency workers underwent decontamination and were held for observation as a precaution.
Barr says one of the transport trucks was leaking a toxic substance, but she could not confirm what the substance was. Ministry of the Environment were among those on site of the spill.
One of the tractor trailers ended up spilling a load of corrosive material, fluorosilicic acid, which led to the evacuation of that area of the highway.
"Exposure to the chemical could cause irritation to the nose, throat, respiratory system, irritation, redness or swelling of the skin and severe eye irritation", Quinn said. Numerous vehicles involved still haven't been removed from the scene.
Multiple chain reaction crashes then followed the initial collisions.
Most of those who were transported to hospital Tuesday, including 13 first responders, were first sent to a decontamination area where they were hosed down.
The Kingston hospital declared a Code Orange to deal with the accident.
He said there are about 2,200 products classified as "dangerous" under federal transportation regulations, ranging from household goods such as soap or paint to more unsafe chemicals such as those spilled on Tuesday around 2 p.m. on Hwy. 401. All vehicles have been re-routed and all persons with potential chemical exposure have been transported for medical attention.
"The five firefighters, for sure, were involved in trying to rescue this driver who was in his transport, and the three police officers as well", she said. No residential properties were affected and there is no risk to the general public, said the release.
The highway remained closed in both directions between Mallorytown and Lansdowne to allow cleanup crews to do their job. Gebremedhin said the consultants used a vacuum truck to collect acid from the leaking containers and a stabilizer was applied to the ground to neutralize acid that could not be directly pumped from the accident scene.