Portland, Oregon police posted a warning to Twitter Saturday evening that “milkshakes” thrown during the violent Antifa protests contained quick-drying cement. Police officers, Quillette journalist Andy Ngo and others were hit with milkshakes. Commenters online noted the high alkaline content of the moistened quick-drying cement would cause chemical burns when it hit exposed skin.

Michelle Malkin set up a GoFund me account for Ngo, who was also beaten and robbed during the attack.

“PPB advising crowd to get out of street and onto sidewalks. Police have been hit with eggs and milkshakes.”

“Police have received information that some of the milkshakes thrown today during the demonstration contained quick-drying cement. We are encouraging anyone hit with a substance today to report it to police.”

PPB advising crowd to get out of street and onto sidewalks. Police have been hit with eggs and milkshakes. — Portland Police (@PortlandPolice) June 29, 2019

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Police have received information that some of the milkshakes thrown today during the demonstration contained quick-drying cement. We are encouraging anyone hit with a substance today to report it to police. — Portland Police (@PortlandPolice) June 29, 2019

Video posted by Oregonian reporter Jim Ryan shows Antifa distributing milkshakes.

Milkshakes for protesters at Sixth and Morrison. pic.twitter.com/ZWkuBzf1TF — Jim Ryan (@Jimryan015) June 29, 2019

Ryan filmed the vicious attack on Andy Ngo by Antifa thugs.

First skirmish I’ve seen. Didn’t see how this started, but @MrAndyNgo got roughed up. pic.twitter.com/hDkfQchRhG — Jim Ryan (@Jimryan015) June 29, 2019

Quick-drying cement can have a pH above 12, so it is fairly strongly alkaline. If a substance has a pH above 11.5, it can cause serious and permanent injury to the eyes in a short time, to say nothing of the damage it can do to other tissues. The assault on @MrAndyNgo is serious. — James Lindsay (@ConceptualJames) June 30, 2019

The National Capital Poison Control Center says of concrete:

…Cement can cause caustic injury, resulting in chemical burns of any part of the body it comes in contact with – skin and eyes, mouth and throat if swallowed, and lungs if cement powder is inhaled. Cement is largely made up of calcium oxide. When it reacts with water, it produces highly alkaline (high pH) calcium hydroxide that can reach a pH of 12 or higher within a couple of minutes. This is why dry cement is less caustic than wet cement. Remember that the pH tells us how acidic or alkaline a solution is on a scale of 0 (most acidic) to 14 (most alkaline), with a neutral pH being about 7. So, because the pH of wet cement is so high, it can cause burns. Some of the worst outcomes occur when cement gets into or seeps through boots, gloves, or clothing. By the time the person is aware of this, significant burns to the skin could have already occurred. The longer the cement stays on the skin, the more damaging the burn can be. Even after washing the cement off, the alkaline burn usually gets worse before it gets better. In severe cases of cement burn of the skin, the burn can extend deeper into tissues beneath the skin to damage muscle and even bone. Other skin problems can also occur from cement. It’s gritty and contains chemicals that can cause dermatitis characterized by redness, swelling, and itching. Swallowing cement can cause burns of the lips, mouth, throat, and stomach. Initial signs can include drooling, difficulty swallowing, or vomiting. In some cases, cement can harden in the gastrointestinal tract and cause obstruction. Inhaling cement dust can cause coughing, wheezing, and difficulty breathing…

Fellow Quillette write Barrett Wilson posted an update on Ngo.

“UPDATE: @MrAndyNgo has suffered multiple injuries to his face and neck and has a torn earlobe. The milkshakes apparently contained quick-drying cement. He’s in the hospital w/ a friend. Journalist @michellemalkin set up a GoFundMe. Suspects still at large.”

UPDATE: @MrAndyNgo has suffered multiple injuries to his face and neck and has a torn earlobe. The milkshakes apparently contained quick-drying cement. He's in the hospital w/ a friend. Journalist @michellemalkin set up a GoFundMe. Suspects still at largehttps://t.co/lKWcaVAEnP — Barrett Wilson (@BarrettWilson6) June 29, 2019

U.S. Ambassador to Germany Richard Grenell condemned the attack on Ngo.

This is unacceptable. I am outraged. This violence from intolerants must stop. Portland leaders must be held to account. https://t.co/yONbNUL2cD — Richard Grenell (@RichardGrenell) June 29, 2019

Andy Ngo posted video after the attack as police interviewed and examined him.

UPDATE: