GENOA, Italy (AP) _ Port workers went on strike Monday to protest fumes from a freighter carrying 12,000 drums of toxic chemical waste, delaying the unloading of the vessel that's been dubbed the ''ship of poison.''

Officials said the Syrian freighter Zanoobia would not be unloaded until the chemicals are analyzed and damaged containers repacked, which could take several weeks.

Four crewmen were treated for nausea and stomach pains, possibly caused by months of exposure to the toxic cargo. Three of the crewmen were released and the fourth was admitted for observation, doctors at San Martino Hospital said.

The 2,200 tons of toxic chemical waste, produced in Italy, have roamed the seas for 15 months in search of a port that would dispose of them. Djibouti, Venezuela, Syria and Greece refused.

The Zanoobia, third ship to carry the chemicals, docked in Genoa on Sunday after officials agreed to accept and burn the cargo.

Lawyers for the ship's owner, Tabalo Shipping, say two people have died: a boy in Venezuela and a Zanoobia crewman.

On Monday, the vessel was moved to an isolated dock after hundreds of port workers walked off their jobs to protest the smell. Unions said the protest prevented seven other freighters from unloading.

Ahmed Tabalo, captain of the Zanoobia, said some drums of chemical waste, which has not been identified, are damaged and may be leaking. Five crewmen were hospitalized earlier this month.

''The condition of my crew is very bad,'' Tabalo said after docking in Genoa. ''For three months we have not entered a port. Now we are all nauseous and sick to the stomach.''

His ship had been moored off Carrara in northern Italy since April 26 seeking permission to unload the cargo, which was shipped from that port in February 1987.

Francesco Rizzuto, a lawyer for Tabalo Shipping, said a group of Italian chemical companies paid the Milan-based company Jelly Wax about 36 cents a pound to dispose of the waste but the company shipped it out of the country instead.

It went first to Djibouti in East Africa, which rejected it. The cargo was unloaded in Venezuela but ordered shipped out when the boy died, reportedly after playing near an opened drum, a lawyer for the shipping company said.

After that, the cargo went to Syria and Greece.

A Zanoobia crewman died during the trip from Greece to Carrara. Lawyers for Tabalo Shipping have asked Italian prosecutors to file charges against Jelly Wax if the death is shown to have resulted from contamination.

Officials said the waste will be burned at a Genoa incinerator at a cost of between 72 cents and $1.86 a pound.