THE HAGUE, Netherlands (AP) _ Countries who signed the new chemical arms treaty now in effect began the painstaking task today of hammering out ways to enforce the ban on killer poisons.

``One of the most monstrous tools of warfare has been ruled intolerable. You have been summoned by history and you have answered its call,'' U.N. Secretary-General Kofi Annan told delegates from many of the 88 nations that have ratified the Chemical Weapons Convention.

``It is not merely a gray step in the cause of disarmament and nonproliferation. It is not merely a signal of restraint and discipline in war,'' Annan said. ``It is much more. It is a momentous act of peace.''

The goal of the three-week conference, the first gathering of all treaty members: Find ways to make sure the treaty meets its goal of forever eliminating the threat of deadly chemical warfare.

Although 165 countries have signed the treaty, which took effect last month, only the 88 have ratified it. The United States, which signed on in 1993, ratified it just two weeks ago.

Hailing the treaty as ``a landmark agreement,'' Annan today called on all other nations that haven't signed to do so.

``While the ratification process worldwide has gained new momentum, I urge that all the signatories _ indeed all 185 members of the United Nations _ finish the job that has begun and join the community of ratifying states,'' he said.

The international convention prohibits the use, production, stockpiling and transfer of chemical weapons. Skeptics say it remains flawed until countries like Russia and Iraq, which have acknowledged having chemical arsenals, also join the accord.

Russia has signed the treaty but its parliament has not ratified it. A Pentagon report three months ago said Russian pesticide processing plants offer ``easy potential'' for secret production of a new generation of chemical weapons.

The United States and Russia both have pledged to destroy their entire stocks of chemical weapons, but that task is proving more difficult and costly than either had anticipated. The United States expects to spend at least $12.4 billion to get rid of its chemical weapons by 2004.

Of greater concern are countries hostile to the West, such as Iraq, Syria, Libya and North Korea, which have yet to even sign the pact.

Iraq, which invaded Kuwait in 1990, had a large clandestine chemical weapons program, and it remains unclear whether the Iraqis actually used some of those weapons during the Persian Gulf War in 1991. And North Korea has large numbers of chemical weapons stored near the Demilitarized Zone that divides it from South Korea.

The treaty is administered under the auspices of the United Nations and by the Organization for the Prohibition of Chemical Weapons, based in The Hague.

Since February 1993, a preparatory commission has been meeting here to draw up the labyrinth of procedures needed to implement the ban.

Today, delegates began tackling numerous organizational and administrative issues, as well as approving verification procedures for the treaty.

``What you have done of your own free will is to announce to this and all succeeding generations that chemical weapons are instruments that no state with any respect for itself and no people with any sense of dignity would use in conflicts _ whether domestic or international,'' Annan said.

Treaty foes have long argued that the treaty will not reduce the chemical arsenals of rogue countries, and that the treaty's provisions cannot be verified.

The convention also allows participating states to demand spot inspections in other member-states. Under the treaty, inspectors must be allowed to cordon off a site within 48 hours to prevent materials from being removed.