The title is a bit misleading. ICAO as such does not reject things, not do they " vote" It works by consensus in issuing standards and it is up to individual States to follow or file a difference.
This " vote" was inside a panel, like an advisory working group, and it is an unusual procedure. ...
There is nothing "unusual" about the vote or the procedure. All changes to the Dangerous Goods Technical Instructions must be voted on; Council approval requires a simple majority.
Dangerous Goods Technical Instructions are different from other ICAO standards/recommendations because States are generally
required to comply by Annex 18 or must file a variation:
ANNEX 18
2.2.1 Each Contracting State shall take the necessary measures to achieve compliance with the detailed provisions
contained in the Technical Instructions. Each Contracting State shall also take the necessary measures to achieve compliance
with any amendment to the Technical Instructions which may be published during the specified period of applicability of an
edition of the Technical Instructions.
Furthermore, most States
automatically incorporate amendments to the Technical Instructions as part of the law. In the US, for example, the Technical Instructions are incorporated into regulations by 49 CFR Part 171, Subpart C:
49 CFR § 171.22 Authorization and conditions for the use of international standards and regulations.
(a) Authorized international standards and regulations. This subpart authorizes, with certain conditions and limitations, the offering for transportation and the transportation in commerce of hazardous materials in accordance with the International Civil Aviation Organization's Technical Instructions for the Safe Transport of Dangerous Goods by Air (ICAO Technical Instructions) ...
In fact, specifically for lithium batteries, the US Congress
prohibits the FAA from unilaterally issuing any requirement more stringent from the Technical Instructions, other than an emergency basis, unless there is a mountain of evidence that lithium batteries are a substantial threat to air safety.
From the 2012 FAA Modernization and Reform Act:
SEC. 828. AIR TRANSPORTATION OF LITHIUM CELLS AND BATTERIES.
(a) IN GENERAL.—The Secretary of Transportation, including a
designee of the Secretary, may not issue or enforce any regulation
or other requirement regarding the transportation by aircraft of lithium
metal cells or batteries or lithium ion cells or batteries, whether
transported separately or packed with or contained in equipment, if
the requirement is more stringent than the requirements of the
ICAO Technical Instructions.
So yeah this carries a lot of weight.